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• Great event : Microsoft Visual Studio 2010 Launch @ Microsoft TechEd Blore

  - by sathya

  Great event : Microsoft Visual Studio 2010 Launch @ Microsoft TechEd Blore   I was really excited on attending the day 1 of Microsoft TechEd 2010 in Bangalore. This is the first Teched that am attending. The event was really fun filled with lot of knowledge sharing sessions and lots of goodies and gifts by the partners Initially the Event Started by Murthy's Session. He explained about the Developers relating to the 5 elements of nature (Pancha Boothaas) 1. Fire - Passion 2. Wave (Water) - Catch the right wave which we need to apply. 3. Earth - Connections and lots of opportunities around the world 4. Air -  Its whatever we breathe. Developers.. Without them nothing is possible. they are like the air 5. Sky - Cloud based applications   Next the Keynote and the announcement of Visual Studio by SomaSegar. List of things that he delivered his speech on : 1. Announcement of Visual Studio 2010 2. Announcement of .NET 4.0 3. Announcement of Silverlight later this week 4. What is the current Trend? Microsoft has done a research with many developers across the globe and have got the following feedback from the users. Get Lost (interrupted) - When we do some work and somebody is calling or interrepting by someother way we lose track of what we were doing and we need to do from the start Falling Behind- Technology gets updated  phenomenally over a period of time and developers always have a scenario like they are not in the state of the art technology and they always have a doubt whether they are staying updated. Lack of Collobaration - When a Manager asks a person what the team members have done and some might be done and some might not be and finally all are into a state like we dont know where we are. So they have addressed these 3 points in the VS 2010 by the following features : Get Lost - Some cool features which could overcome this. We have some Graphical interface. which could show what we have done and where we are. Some Zoom features in the code level. Falling Behind - Everything is based on .NET language base. 2010 has been built in such a way that if developers know the native language that's enough for building good applications. Lack of Collobaration - Some Dashboard Features which would show where exactly the project is. And a graphical user interface is shown on clicking which it directly drills down even to the code level. 5. An overview on all new features in VS 2010. 6. Some good demos of new features in VS 2010 by Polita and one more girl. Some of the new features included : 1. Team Explorer 2. Zoom in Code 3. Ribbon Development 4. Development in Single Platform for Windows Phone, XBox, Zune, Azure, Web Based and Windows based applications 5. Sequence Diagram Generation directly from code 6. Dashboards to show project status 7. Javascript and JQuery intellisense 8. Native support for JQuery 9. Packaging feature while deploying. 10. Generation of different versions of web.config like Web.Config.Production, Web.Config.Staging, etc. 11. IntelliTrace - Eliminating the "Not Reproducible" statement. 12. Automated User Interface Testing. At last in the closing of the day we had a great event called Demo Extravaganza, where lot of cool projects that were launched by Microsoft and also the projects that are under research were also shown. I got a lot of info about Bing today. BING really rocks!!! It has the following : 1. Visual Search 2. Product based search. For each product different menu filters were provided to make an advanced search 3. BING Maps was awesome!! It zoomed in to the street level and we can assume that we are the persons who are walking or running on the road and we can see the real objects like buildings moving by our side. 4. PhotoSynth was used in BING to show up all the images taken around the globe in a 3D format. 5. Formula - If we give some formula it automatically gives the value for the variable or derivation of expression Also some info about some kool touch apps which does an authentication and computation of Teched Attendee's Points that they have scored and the sessions attended. One guy won an XBOX in lucky draw as a gift. There were lot of Partner Stalls like Accenture,Intel,Citrix,MicroFocus,Telerik,infragistics,Sapient etc. Some Offers were provided for us like 50% off on Certifications, 1 free Elearning Course, etc. Stay tuned!! Wil update you on other events too..

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• Deciding On Features For Open Source

  - by Robz / Fervent Coder

  Open source feature selection is subjective. An interesting question was posed to me recently at a presentation - “How do you decide what features to include in the [open source] projects you manage?” Is It Objective? I’d like to say that it’s really objective and that we vote on features and look at what carries the most interest of the populace. Actually no I wouldn’t. I don’t think I would enjoy working on open source (OSS) as much if it someone else decided on what features I should include. It already works that way at work. I don’t want to come home from work and work on things that others decide for me unless they are paying me for those features. So how do I decide on features for our open source projects? I think there are at least three paths to feature selection and they are not necessarily mutually exclusive. Feature Selection IS the Set of Features For the Domain Your product, in whatever domain it is in, needs to have the basic set of features that make it answer the needs of that domain. That is different for every product, but if you take for example a build tool, at the very least it needs to be able to compile source. And these basic needed features are not always objective either. Two people could completely disagree what makes for a required feature to meet a domain need for a product. Even one person may disagree with himself/herself about what features are needed based on different timeframes. So that leads us down to subjective. Feature Selection IS An Answer To Competition Some features go in because the competition adds a feature that may draw others away from your product offering. With OSS, there are all free alternatives, so if your competition adds a killer feature and you don’t, there isn’t much other than learning (how to use the other product) to move your customers off to the competition. If you want to keep your customers, you need to be ready to answer the questions of adding the features your competition has added.  Sometimes it’s about adding a feature that your competition charges for, but you add it for free. That draws people to the free alternative – so sometimes that adds a motivation to select a feature. Sometimes it’s because you want those features in your product, either to learn how you can answer the question of how to do something and/or because you have a need for that feature and you want it in your product. That also leads us down the road to subjective. Feature Selection IS Subjective I decide on features based on what I want to see in the product I am working on. Things I am interested in or have the biggest need for usually get picked first, with things that do not interest me either coming later or not at all. Most people get interested in an area of OSS because it solves a need for them and/or they find it interesting. If one of these two things is not happening and they are not being paid, it’s likely that person will move on to something else they find interesting or just stop OSS altogether. OSS feature selection is just that – subjective. If it wasn’t, it wouldn’t be opinionated and it wouldn’t have a personality about it. Most people like certain OSS because they like where the product is going or the personalities behind the product. For me, I want my products to be easy to use and solve an important problem. If it takes you more than 5-10 minutes to learn how to use my product, I know you are probably going somewhere else. So I pick features that make the product easy to use and learn, and those are not always the simplest features to work on. I work for conventions and make the product opinionated, because I think that is what makes using a product easier, if it already works with little setup. And I like to provide the ability for power users to get in and change the conventions to suit their needs. So those are required features for me above and beyond the domain features. I like to think I do a pretty good job at this. Usually when I present on something I’ve created, I like seeing people’s eyes light up when they see how simple it is to set up a powerful product like UppercuT. Patches And/Or Donations But remember before you say I’m a bad person or won’t use my product, I’ll always accept patches or I might like the feature that you suggest. If you like using the products I provide and they solve a problem for you the two biggest compliments you can provide are either a patch or a donation.  If you think the product is great, but if it could do this one other thing, it would be awesome(!), then consider contacting me and providing a patch, or consider contacting me with a donation and a request to put the feature in. And alternatively, if it’s a big feature, you could hire me to work on the product to make it even better. What If There Are Multiple Committers? In the question of multiple committers, I choose that someone always makes the ultimate decision to select whether a feature should be part of a product or not. But for other OSS project maybe this is not the case. If there is not an ultimate decision maker, then there is the possibility of either adding every feature suggested or having a deadlock on two conflicting features.   So let me pose this question. If you work on Open Source, how do you decide on what features to put in your open source projects? How do you decide what doesn’t belong? What do you do when there are conflicting features?

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• JavaOne 2011: Content review process and Tips for submissions

  - by arungupta

  The Technical Sessions, Birds of Feather, Panels, and Hands-on labs (basically all the content delivered at JavaOne) forms the backbone of the conference. At this year's JavaOne conference you'll have access to the rock star speakers, the ability to engage with luminaries in the hallways, and have beer (or 2) with community peers in designated areas. Even though the conference is Oct 2-6, 2011, and will be bigger and better than last year's conference, the Call for Paper submission and review/selection evaluation started much earlier.In previous years, I've participated in the review process and this year I was honored to serve as co-lead for the "Enterprise Service Architecture and Cloud" track with Ludovic Champenois. We had a stellar review team with an equal mix of Oracle and external community reviewers. The review process is very overwhelming with the reviewers going through multiple voting iterations on each submission in order to ensure that the selected content is the BEST of the submitted lot. Our ultimate goal was to ensure that the content best represented the track, and most importantly would draw interest and excitement from attendees. As always, the number and quality of submissions were just superb, making for a truly challenging (and rewarding) experience for the reviewers. As co-lead I tried to ensure that I applied a fair and balanced process in the evaluation of content in my track. . Here are some key steps followed by all track leads: Vote on sessions - Each reviewer is required to vote on the sessions on a scale of 1-5 - and also provide a justifying comment. Create buckets - Divide the submissions into different buckets to ensure a fair representation of different topics within a track. This ensures that if a particular bucket got higher votes then the track is not exclusively skewed towards it. Top 7 - The review committee provides a list of the top 7 talks that can be used in the promotional material by the JavaOne team. Generally these talks are easy to identify and a consensus is reached upon them fairly quickly. First cut - Each track is allocated a total number of sessions (including panels), BoFs, and Hands-on labs that can be approved. The track leads then start creating the first cut of the approvals using the casted votes coupled with their prior experience in the subject matter. In our case, Ludo and I have been attending/speaking at JavaOne (and other popular Java-focused conferences) for double digit years. The Grind - The first cut is then refined and refined and refined using multiple selection criteria such as sorting on the bucket, speaker quality, topic popularity, cumulative vote total, and individual vote scale. The sessions that don't make the cut are reviewed again as well to ensure if they need to replace one of the selected one as a potential alternate. I would like to thank the entire Java community for all the submissions and many thanks to the reviewers who spent countless hours reading each abstract, voting on them, and helping us refine the list. I think approximately 3-4 hours cumulative were spent on each submission to reach an evaluation, specifically the border line cases. We gave our recommendations to the JavaOne Program Committee Chairperson (Sharat Chander) and accept/decline notifications should show up in submitter inboxes in the next few weeks. Here are some points to keep in mind when submitting a session to JavaOne next time: JavaOne is a technology-focused conference so any product, marketing or seemingly marketish talk are put at the bottom of the list.Oracle Open World and Oracle Develop are better options for submitting product specific talks. Make your title catchy. Remember the attendees are more likely to read the abstract if they like the title. We try our best to recategorize the talk to a different track if it needs to but please ensure that you are filing in the right track to have all the right eyeballs looking at it. Also, it does not hurt marking an alternate track if your talk meets the criteria. Make sure to coordinate within your team before the submission - multiple sessions from the same team or company does not ensure that the best speaker is picked. In such case we rely upon your "google presence" and/or review committee's prior knowledge of the speaker. The reviewers may not know you or your product at all and you get 750 characters to pitch your idea. Make sure to use all of them, to the last 750th character. Make sure to read your abstract multiple times to ensure that you are giving all the relevant information ? Think through your presentation and see if you are leaving out any important aspects.Also look if the abstract has any redundant information that will not required by the reviewers. There are additional sections that allow you to share information about the speaker and the presentation summary. Use them to blow the horn about yourself and any other relevant details. Please don't say "call me at xxx-xxx-xxxx to find out the details" :-) The review committee enjoyed reviewing the submissions and we certainly hope you'll have a great time attending them. Happy JavaOne!

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• JavaOne 2011: Content review process and Tips for submissions

  - by arungupta

  The Technical Sessions, Birds of Feather, Panels, and Hands-on labs (basically all the content delivered at JavaOne) forms the backbone of the conference. At this year's JavaOne conference you'll have access to the rock star speakers, the ability to engage with luminaries in the hallways, and have beer (or 2) with community peers in designated areas. Even though the conference is Oct 2-6, 2011, and will be bigger and better than last year's conference, the Call for Paper submission and review/selection evaluation started much earlier.In previous years, I've participated in the review process and this year I was honored to serve as co-lead for the "Enterprise Service Architecture and Cloud" track with Ludovic Champenois. We had a stellar review team with an equal mix of Oracle and external community reviewers. The review process is very overwhelming with the reviewers going through multiple voting iterations on each submission in order to ensure that the selected content is the BEST of the submitted lot. Our ultimate goal was to ensure that the content best represented the track, and most importantly would draw interest and excitement from attendees. As always, the number and quality of submissions were just superb, making for a truly challenging (and rewarding) experience for the reviewers. As co-lead I tried to ensure that I applied a fair and balanced process in the evaluation of content in my track. . Here are some key steps followed by all track leads: Vote on sessions - Each reviewer is required to vote on the sessions on a scale of 1-5 - and also provide a justifying comment. Create buckets - Divide the submissions into different buckets to ensure a fair representation of different topics within a track. This ensures that if a particular bucket got higher votes then the track is not exclusively skewed towards it. Top 7 - The review committee provides a list of the top 7 talks that can be used in the promotional material by the JavaOne team. Generally these talks are easy to identify and a consensus is reached upon them fairly quickly. First cut - Each track is allocated a total number of sessions (including panels), BoFs, and Hands-on labs that can be approved. The track leads then start creating the first cut of the approvals using the casted votes coupled with their prior experience in the subject matter. In our case, Ludo and I have been attending/speaking at JavaOne (and other popular Java-focused conferences) for double digit years. The Grind - The first cut is then refined and refined and refined using multiple selection criteria such as sorting on the bucket, speaker quality, topic popularity, cumulative vote total, and individual vote scale. The sessions that don't make the cut are reviewed again as well to ensure if they need to replace one of the selected one as a potential alternate. I would like to thank the entire Java community for all the submissions and many thanks to the reviewers who spent countless hours reading each abstract, voting on them, and helping us refine the list. I think approximately 3-4 hours cumulative were spent on each submission to reach an evaluation, specifically the border line cases. We gave our recommendations to the JavaOne Program Committee Chairperson (Sharat Chander) and accept/decline notifications should show up in submitter inboxes in the next few weeks. Here are some points to keep in mind when submitting a session to JavaOne next time: JavaOne is a technology-focused conference so any product, marketing or seemingly marketish talk are put at the bottom of the list.Oracle Open World and Oracle Develop are better options for submitting product specific talks. Make your title catchy. Remember the attendees are more likely to read the abstract if they like the title. We try our best to recategorize the talk to a different track if it needs to but please ensure that you are filing in the right track to have all the right eyeballs looking at it. Also, it does not hurt marking an alternate track if your talk meets the criteria. Make sure to coordinate within your team before the submission - multiple sessions from the same team or company does not ensure that the best speaker is picked. In such case we rely upon your "google presence" and/or review committee's prior knowledge of the speaker. The reviewers may not know you or your product at all and you get 750 characters to pitch your idea. Make sure to use all of them, to the last 750th character. Make sure to read your abstract multiple times to ensure that you are giving all the relevant information ? Think through your presentation and see if you are leaving out any important aspects.Also look if the abstract has any redundant information that will not required by the reviewers. There are additional sections that allow you to share information about the speaker and the presentation summary. Use them to blow the horn about yourself and any other relevant details. Please don't say "call me at xxx-xxx-xxxx to find out the details" :-) The review committee enjoyed reviewing the submissions and we certainly hope you'll have a great time attending them. Happy JavaOne!

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• Choosing a VS project type (C++)

  - by typoknig

  Hi all, I do not use C++ much (I try to stick to the easier stuff like Java and VB.NET), but the lately I have not had a choice. When I am picking a project type in VS for some C++ source I download, what project type should I pick? I had just been sticking with Win32 Console Applications, but I just downloaded some code (below) that will not work right even when it compiles with out errors. I have tried to use a CLR Console Application and an empty project too, and have changed many variables along the way, but I cannot get this code to work. I noticed that this code does not have "int main()" at its beginning, does that have something to do with it? Anyways, here is the code, got it from here: /* Demo of modified Lucas-Kanade optical flow algorithm. See the printf below */ #ifdef _CH_ #pragma package <opencv> #endif #ifndef _EiC #include "cv.h" #include "highgui.h" #include <stdio.h> #include <ctype.h> #endif #include <windows.h> #define FULL_IMAGE_AS_OUTPUT_FILE #define cvMirror cvFlip //IplImage *image = 0, *grey = 0, *prev_grey = 0, *pyramid = 0, *prev_pyramid = 0, *swap_temp; IplImage **buf = 0; IplImage *image1 = 0; IplImage *imageCopy=0; IplImage *image = 0; int win_size = 10; const int MAX_COUNT = 500; CvPoint2D32f* points[2] = {0,0}, *swap_points; char* status = 0; //int count = 0; //int need_to_init = 0; //int night_mode = 0; int flags = 0; //int add_remove_pt = 0; bool bLButtonDown = false; //bool bstopLoop = false; CvPoint pt, pt1,pt2; //IplImage* img1; FILE* FileDest; char* strImageDir = "E:\\Projects\\TSCreator\\Images"; char* strItemName = "b"; int imageCount=0; int bFirstFace = 1; // flag for first face int mode = 1; // Mode 1 - Haar Traing Sample Creation, 2 - HMM sample creation, Mode = 3 - Both Harr and HMM. //int startImgeNo = 1; bool isEqualRation = false; //Weidth to height ratio is equal //Selected Image data IplImage *selectedImage = 0; int selectedX = 0, selectedY = 0, currentImageNo = 0, selectedWidth = 0, selectedHeight= 0; CvRect selectedROI; void saveFroHarrTraining(IplImage *src, int x, int y, int width, int height, int imageCount); void saveForHMMTraining(IplImage *src, CvRect roi,int imageCount); // Code for draw ROI Cropping Image void on_mouse( int event, int x, int y, int flags, void* param ) { char f[200]; CvRect reg; if( !image ) return; if( event == CV_EVENT_LBUTTONDOWN ) { bLButtonDown = true; pt1.x = x; pt1.y = y; } else if ( event == CV_EVENT_MOUSEMOVE ) //Draw the selected area rectangle { pt2.x = x; pt2.y = y; if(bLButtonDown) { if( !image1 ) { /* allocate all the buffers */ image1 = cvCreateImage( cvGetSize(image), 8, 3 ); image1->origin = image->origin; points[0] = (CvPoint2D32f*)cvAlloc(MAX_COUNT*sizeof(points[0][0])); points[1] = (CvPoint2D32f*)cvAlloc(MAX_COUNT*sizeof(points[0][0])); status = (char*)cvAlloc(MAX_COUNT); flags = 0; } cvCopy( image, image1, 0 ); //Equal Weight-Height Ratio if(isEqualRation) { pt2.y = pt1.y + (pt2.x-pt1.x); } //Max Height and Width is the image width and height if(pt2.x>image->width) { pt2.x = image->width; } if(pt2.y>image->height) { pt2.y = image->height; } CvPoint InnerPt1 = pt1; CvPoint InnerPt2 = pt2; if ( InnerPt1.x > InnerPt2.x) { int tempX = InnerPt1.x; InnerPt1.x = InnerPt2.x; InnerPt2.x = tempX; } if ( pt2.y < InnerPt1.y ) { int tempY = InnerPt1.y; InnerPt1.y = InnerPt2.y; InnerPt2.y = tempY; } InnerPt1.y = image->height - InnerPt1.y; InnerPt2.y = image->height - InnerPt2.y; CvFont font; double hScale=1.0; double vScale=1.0; int lineWidth=1; cvInitFont(&font,CV_FONT_HERSHEY_SIMPLEX|CV_FONT_ITALIC, hScale,vScale,0,lineWidth); char size [200]; reg.x = pt1.x; reg.y = image->height - pt2.y; reg.height = abs (pt2.y - pt1.y); reg.width = InnerPt2.x -InnerPt1.x; //print width and heght of the selected reagion sprintf(size, "(%dx%d)",reg.width, reg.height); cvPutText (image1,size,cvPoint(10,10), &font, cvScalar(255,255,0)); cvRectangle(image1, InnerPt1, InnerPt2, CV_RGB(255,0,0), 1); //Mark Selected Reagion selectedImage = image; selectedX = pt1.x; selectedY = pt1.y; selectedWidth = reg.width; selectedHeight = reg.height; selectedROI = reg; //Show the modified image cvShowImage("HMM-Harr Positive Image Creator",image1); } } else if ( event == CV_EVENT_LBUTTONUP ) { bLButtonDown = false; // pt2.x = x; // pt2.y = y; // // if ( pt1.x > pt2.x) // { // int tempX = pt1.x; // pt1.x = pt2.x; // pt2.x = tempX; // } // // if ( pt2.y < pt1.y ) // { // int tempY = pt1.y; // pt1.y = pt2.y; // pt2.y = tempY; // // } // //reg.x = pt1.x; //reg.y = image->height - pt2.y; // //reg.height = abs (pt2.y - pt1.y); ////reg.width = reg.height/3; //reg.width = pt2.x -pt1.x; ////reg.height = (2 * reg.width)/3; #ifdef FULL_IMAGE_AS_OUTPUT_FILE CvRect FullImageRect; FullImageRect.x = 0; FullImageRect.y = 0; FullImageRect.width = image->width; FullImageRect.height = image->height; IplImage *regionFullImage =0; regionFullImage = cvCreateImage(cvSize (FullImageRect.width, FullImageRect.height), image->depth, image->nChannels); image->roi = NULL; //cvSetImageROI (image, FullImageRect); //cvCopy (image, regionFullImage, 0); #else IplImage *region =0; region = cvCreateImage(cvSize (reg.width, reg.height), image1->depth, image1->nChannels); image->roi = NULL; cvSetImageROI (image1, reg); cvCopy (image1, region, 0); #endif //cvNamedWindow("Result", CV_WINDOW_AUTOSIZE); //selectedImage = image; //selectedX = pt1.x; //selectedY = pt1.y; //selectedWidth = reg.width; //selectedHeight = reg.height; ////currentImageNo = startImgeNo; //selectedROI = reg; /*if(mode == 1) { saveFroHarrTraining(image,pt1.x,pt1.y,reg.width,reg.height,startImgeNo); } else if(mode == 2) { saveForHMMTraining(image,reg,startImgeNo); } else if(mode ==3) { saveFroHarrTraining(image,pt1.x,pt1.y,reg.width,reg.height,startImgeNo); saveForHMMTraining(image,reg,startImgeNo); } else { printf("Invalid mode."); } startImgeNo++;*/ } } /* Save popsitive samples for Harr Training. Also add an entry to the PositiveSample.txt with the location of the item of interest. */ void saveFroHarrTraining(IplImage *src, int x, int y, int width, int height, int imageCount) { char f[255] ; sprintf(f,"%s\\%s\\harr_%s%d%d.jpg",strImageDir,strItemName,strItemName,imageCount/10, imageCount%10); cvNamedWindow("Harr", CV_WINDOW_AUTOSIZE); cvShowImage("Harr", src); cvSaveImage(f, src); printf("output%d%d \t ", imageCount/10, imageCount%10); printf("width %d \t", width); printf("height %d \t", height); printf("x1 %d \t", x); printf("y1 %d \t\n", y); char f1[255]; sprintf(f1,"%s\\PositiveSample.txt",strImageDir); FileDest = fopen(f1, "a"); fprintf(FileDest, "%s\\harr_%s%d.jpg 1 %d %d %d %d \n",strItemName,strItemName, imageCount, x, y, width, height); fclose(FileDest); } /* Create Sample Images for HMM recognition algorythm trai ning. */ void saveForHMMTraining(IplImage *src, CvRect roi,int imageCount) { char f[255] ; printf("x=%d, y=%d, w= %d, h= %d\n",roi.x,roi.y,roi.width,roi.height); //Create the file name sprintf(f,"%s\\%s\\hmm_%s%d.pgm",strImageDir,strItemName,strItemName, imageCount); //Create storage for grayscale image IplImage* gray = cvCreateImage(cvSize(roi.width,roi.height), 8, 1); //Create storage for croped reagon IplImage* regionFullImage = cvCreateImage(cvSize(roi.width,roi.height),8,3); //Croped marked region cvSetImageROI(src,roi); cvCopy(src,regionFullImage); cvResetImageROI(src); //Flip croped image - otherwise it will saved upside down cvConvertImage(regionFullImage, regionFullImage, CV_CVTIMG_FLIP); //Convert croped image to gray scale cvCvtColor(regionFullImage,gray, CV_BGR2GRAY); //Show final grayscale image cvNamedWindow("HMM", CV_WINDOW_AUTOSIZE); cvShowImage("HMM", gray); //Save final grayscale image cvSaveImage(f, gray); } int maina( int argc, char** argv ) { CvCapture* capture = 0; //if( argc == 1 || (argc == 2 && strlen(argv[1]) == 1 && isdigit(argv[1][0]))) // capture = cvCaptureFromCAM( argc == 2 ? argv[1][0] - '0' : 0 ); //else if( argc == 2 ) // capture = cvCaptureFromAVI( argv[1] ); char* video; if(argc ==7) { mode = atoi(argv[1]); strImageDir = argv[2]; strItemName = argv[3]; video = argv[4]; currentImageNo = atoi(argv[5]); int a = atoi(argv[6]); if(a==1) { isEqualRation = true; } else { isEqualRation = false; } } else { printf("\nUsage: TSCreator.exe <Mode> <Sample Image Save Path> <Sample Image Save Directory> <Video File Location> <Start Image No> <Is Equal Ratio>\n"); printf("Mode = 1 - Haar Traing Sample Creation. \nMode = 2 - HMM sample creation.\nMode = 3 - Both Harr and HMM\n"); printf("Is Equal Ratio = 0 or 1. 1 - Equal weidth and height, 0 - custom."); printf("Note: You have to create the image save directory in correct path first.\n"); printf("Eg: TSCreator.exe 1 E:\Projects\TSCreator\Images A 11.avi 1 1\n\n"); return 0; } capture = cvCaptureFromAVI(video); if( !capture ) { fprintf(stderr,"Could not initialize capturing...\n"); return -1; } cvNamedWindow("HMM-Harr Positive Image Creator", CV_WINDOW_AUTOSIZE); cvSetMouseCallback("HMM-Harr Positive Image Creator", on_mouse, 0); //cvShowImage("Test", image1); for(;;) { IplImage* frame = 0; int i, k, c; frame = cvQueryFrame( capture ); if( !frame ) break; if( !image ) { /* allocate all the buffers */ image = cvCreateImage( cvGetSize(frame), 8, 3 ); image->origin = frame->origin; //grey = cvCreateImage( cvGetSize(frame), 8, 1 ); //prev_grey = cvCreateImage( cvGetSize(frame), 8, 1 ); //pyramid = cvCreateImage( cvGetSize(frame), 8, 1 ); // prev_pyramid = cvCreateImage( cvGetSize(frame), 8, 1 ); points[0] = (CvPoint2D32f*)cvAlloc(MAX_COUNT*sizeof(points[0][0])); points[1] = (CvPoint2D32f*)cvAlloc(MAX_COUNT*sizeof(points[0][0])); status = (char*)cvAlloc(MAX_COUNT); flags = 0; } cvCopy( frame, image, 0 ); // cvCvtColor( image, grey, CV_BGR2GRAY ); cvShowImage("HMM-Harr Positive Image Creator", image); cvSetMouseCallback("HMM-Harr Positive Image Creator", on_mouse, 0); c = cvWaitKey(0); if((char)c == 's') { //Save selected reagion as training data if(selectedImage) { printf("Selected Reagion Saved\n"); if(mode == 1) { saveFroHarrTraining(selectedImage,selectedX,selectedY,selectedWidth,selectedHeight,currentImageNo); } else if(mode == 2) { saveForHMMTraining(selectedImage,selectedROI,currentImageNo); } else if(mode ==3) { saveFroHarrTraining(selectedImage,selectedX,selectedY,selectedWidth,selectedHeight,currentImageNo); saveForHMMTraining(selectedImage,selectedROI,currentImageNo); } else { printf("Invalid mode."); } currentImageNo++; } } } cvReleaseCapture( &capture ); //cvDestroyWindow("HMM-Harr Positive Image Creator"); cvDestroyAllWindows(); return 0; } #ifdef _EiC main(1,"lkdemo.c"); #endif If I put... #include "stdafx.h" int _tmain(int argc, _TCHAR* argv[]) { return 0; } ... before the previous code (and link it to the correct OpenCV .lib files) it compiles without errors, but does nothing at the command line. How do I make it work?

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• UIImagePickerController, UIImage, Memory and More!

  - by Itay

  I've noticed that there are many questions about how to handle UIImage objects, especially in conjunction with UIImagePickerController and then displaying it in a view (usually a UIImageView). Here is a collection of common questions and their answers. Feel free to edit and add your own. I obviously learnt all this information from somewhere too. Various forum posts, StackOverflow answers and my own experimenting brought me to all these solutions. Credit goes to those who posted some sample code that I've since used and modified. I don't remember who you all are - but hats off to you! How Do I Select An Image From the User's Images or From the Camera? You use UIImagePickerController. The documentation for the class gives a decent overview of how one would use it, and can be found here. Basically, you create an instance of the class, which is a modal view controller, display it, and set yourself (or some class) to be the delegate. Then you'll get notified when a user selects some form of media (movie or image in 3.0 on the 3GS), and you can do whatever you want. My Delegate Was Called - How Do I Get The Media? The delegate method signature is the following: - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info; You should put a breakpoint in the debugger to see what's in the dictionary, but you use that to extract the media. For example: UIImage* image = [info objectForKey:UIImagePickerControllerOriginalImage]; There are other keys that work as well, all in the documentation. OK, I Got The Image, But It Doesn't Have Any Geolocation Data. What gives? Unfortunately, Apple decided that we're not worthy of this information. When they load the data into the UIImage, they strip it of all the EXIF/Geolocation data. Can I Get To The Original File Representing This Image on the Disk? Nope. For security purposes, you only get the UIImage. How Can I Look At The Underlying Pixels of the UIImage? Since the UIImage is immutable, you can't look at the direct pixels. However, you can make a copy. The code to this looks something like this: UIImage* image = ...; // An image NSData* pixelData = (NSData*) CGDataProviderCopyData(CGImageGetDataProvider(image.CGImage)); unsigned char* pixelBytes = (unsigned char *)[pixelData bytes]; // Take away the red pixel, assuming 32-bit RGBA for(int i = 0; i < [pixelData length]; i += 4) { pixelBytes[i] = 0; // red pixelBytes[i+1] = pixelBytes[i+1]; // green pixelBytes[i+2] = pixelBytes[i+2]; // blue pixelBytes[i+3] = pixelBytes[i+3]; // alpha } However, note that CGDataProviderCopyData provides you with an "immutable" reference to the data - meaning you can't change it (and you may get a BAD_ACCESS error if you do). Look at the next question if you want to see how you can modify the pixels. How Do I Modify The Pixels of the UIImage? The UIImage is immutable, meaning you can't change it. Apple posted a great article on how to get a copy of the pixels and modify them, and rather than copy and paste it here, you should just go read the article. Once you have the bitmap context as they mention in the article, you can do something similar to this to get a new UIImage with the modified pixels: CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage* newImage = [UIImage imageWithCGImage:ref]; Do remember to release your references though, otherwise you're going to be leaking quite a bit of memory. After I Select 3 Images From The Camera, I Run Out Of Memory. Help! You have to remember that even though on disk these images take up only a few hundred kilobytes at most, that's because they're compressed as a PNG or JPG. When they are loaded into the UIImage, they become uncompressed. A quick over-the-envelope calculation would be: width x height x 4 = bytes in memory That's assuming 32-bit pixels. If you have 16-bit pixels (some JPGs are stored as RGBA-5551), then you'd replace the 4 with a 2. Now, images taken with the camera are 1600 x 1200 pixels, so let's do the math: 1600 x 1200 x 4 = 7,680,000 bytes = ~8 MB 8 MB is a lot, especially when you have a limit of around 24 MB for your application. That's why you run out of memory. OK, I Understand Why I Have No Memory. What Do I Do? There is never any reason to display images at their full resolution. The iPhone has a screen of 480 x 320 pixels, so you're just wasting space. If you find yourself in this situation, ask yourself the following question: Do I need the full resolution image? If the answer is yes, then you should save it to disk for later use. If the answer is no, then read the next part. Once you've decided what to do with the full-resolution image, then you need to create a smaller image to use for displaying. Many times you might even want several sizes for your image: a thumbnail, a full-size one for displaying, and the original full-resolution image. OK, I'm Hooked. How Do I Resize the Image? Unfortunately, there is no defined way how to resize an image. Also, it's important to note that when you resize it, you'll get a new image - you're not modifying the old one. There are a couple of methods to do the resizing. I'll present them both here, and explain the pros and cons of each. Method 1: Using UIKit + (UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize; { // Create a graphics image context UIGraphicsBeginImageContext(newSize); // Tell the old image to draw in this new context, with the desired // new size [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)]; // Get the new image from the context UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext(); // End the context UIGraphicsEndImageContext(); // Return the new image. return newImage; } This method is very simple, and works great. It will also deal with the UIImageOrientation for you, meaning that you don't have to care whether the camera was sideways when the picture was taken. However, this method is not thread safe, and since thumbnailing is a relatively expensive operation (approximately ~2.5s on a 3G for a 1600 x 1200 pixel image), this is very much an operation you may want to do in the background, on a separate thread. Method 2: Using CoreGraphics + (UIImage*)imageWithImage:(UIImage*)sourceImage scaledToSize:(CGSize)newSize; { CGFloat targetWidth = targetSize.width; CGFloat targetHeight = targetSize.height; CGImageRef imageRef = [sourceImage CGImage]; CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef); CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef); if (bitmapInfo == kCGImageAlphaNone) { bitmapInfo = kCGImageAlphaNoneSkipLast; } CGContextRef bitmap; if (sourceImage.imageOrientation == UIImageOrientationUp || sourceImage.imageOrientation == UIImageOrientationDown) { bitmap = CGBitmapContextCreate(NULL, targetWidth, targetHeight, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } else { bitmap = CGBitmapContextCreate(NULL, targetHeight, targetWidth, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } if (sourceImage.imageOrientation == UIImageOrientationLeft) { CGContextRotateCTM (bitmap, radians(90)); CGContextTranslateCTM (bitmap, 0, -targetHeight); } else if (sourceImage.imageOrientation == UIImageOrientationRight) { CGContextRotateCTM (bitmap, radians(-90)); CGContextTranslateCTM (bitmap, -targetWidth, 0); } else if (sourceImage.imageOrientation == UIImageOrientationUp) { // NOTHING } else if (sourceImage.imageOrientation == UIImageOrientationDown) { CGContextTranslateCTM (bitmap, targetWidth, targetHeight); CGContextRotateCTM (bitmap, radians(-180.)); } CGContextDrawImage(bitmap, CGRectMake(0, 0, targetWidth, targetHeight), imageRef); CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage* newImage = [UIImage imageWithCGImage:ref]; CGContextRelease(bitmap); CGImageRelease(ref); return newImage; } The benefit of this method is that it is thread-safe, plus it takes care of all the small things (using correct color space and bitmap info, dealing with image orientation) that the UIKit version does. How Do I Resize and Maintain Aspect Ratio (like the AspectFill option)? It is very similar to the method above, and it looks like this: + (UIImage*)imageWithImage:(UIImage*)sourceImage scaledToSizeWithSameAspectRatio:(CGSize)targetSize; { CGSize imageSize = sourceImage.size; CGFloat width = imageSize.width; CGFloat height = imageSize.height; CGFloat targetWidth = targetSize.width; CGFloat targetHeight = targetSize.height; CGFloat scaleFactor = 0.0; CGFloat scaledWidth = targetWidth; CGFloat scaledHeight = targetHeight; CGPoint thumbnailPoint = CGPointMake(0.0,0.0); if (CGSizeEqualToSize(imageSize, targetSize) == NO) { CGFloat widthFactor = targetWidth / width; CGFloat heightFactor = targetHeight / height; if (widthFactor > heightFactor) { scaleFactor = widthFactor; // scale to fit height } else { scaleFactor = heightFactor; // scale to fit width } scaledWidth = width * scaleFactor; scaledHeight = height * scaleFactor; // center the image if (widthFactor > heightFactor) { thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5; } else if (widthFactor < heightFactor) { thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5; } } CGImageRef imageRef = [sourceImage CGImage]; CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef); CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef); if (bitmapInfo == kCGImageAlphaNone) { bitmapInfo = kCGImageAlphaNoneSkipLast; } CGContextRef bitmap; if (sourceImage.imageOrientation == UIImageOrientationUp || sourceImage.imageOrientation == UIImageOrientationDown) { bitmap = CGBitmapContextCreate(NULL, targetWidth, targetHeight, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } else { bitmap = CGBitmapContextCreate(NULL, targetHeight, targetWidth, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } // In the right or left cases, we need to switch scaledWidth and scaledHeight, // and also the thumbnail point if (sourceImage.imageOrientation == UIImageOrientationLeft) { thumbnailPoint = CGPointMake(thumbnailPoint.y, thumbnailPoint.x); CGFloat oldScaledWidth = scaledWidth; scaledWidth = scaledHeight; scaledHeight = oldScaledWidth; CGContextRotateCTM (bitmap, radians(90)); CGContextTranslateCTM (bitmap, 0, -targetHeight); } else if (sourceImage.imageOrientation == UIImageOrientationRight) { thumbnailPoint = CGPointMake(thumbnailPoint.y, thumbnailPoint.x); CGFloat oldScaledWidth = scaledWidth; scaledWidth = scaledHeight; scaledHeight = oldScaledWidth; CGContextRotateCTM (bitmap, radians(-90)); CGContextTranslateCTM (bitmap, -targetWidth, 0); } else if (sourceImage.imageOrientation == UIImageOrientationUp) { // NOTHING } else if (sourceImage.imageOrientation == UIImageOrientationDown) { CGContextTranslateCTM (bitmap, targetWidth, targetHeight); CGContextRotateCTM (bitmap, radians(-180.)); } CGContextDrawImage(bitmap, CGRectMake(thumbnailPoint.x, thumbnailPoint.y, scaledWidth, scaledHeight), imageRef); CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage* newImage = [UIImage imageWithCGImage:ref]; CGContextRelease(bitmap); CGImageRelease(ref); return newImage; } The method we employ here is to create a bitmap with the desired size, but draw an image that is actually larger, thus maintaining the aspect ratio. So We've Got Our Scaled Images - How Do I Save Them To Disk? This is pretty simple. Remember that we want to save a compressed version to disk, and not the uncompressed pixels. Apple provides two functions that help us with this (documentation is here): NSData* UIImagePNGRepresentation(UIImage *image); NSData* UIImageJPEGRepresentation (UIImage *image, CGFloat compressionQuality); And if you want to use them, you'd do something like: UIImage* myThumbnail = ...; // Get some image NSData* imageData = UIImagePNGRepresentation(myThumbnail); Now we're ready to save it to disk, which is the final step (say into the documents directory): // Give a name to the file NSString* imageName = @"MyImage.png"; // Now, we have to find the documents directory so we can save it // Note that you might want to save it elsewhere, like the cache directory, // or something similar. NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString* documentsDirectory = [paths objectAtIndex:0]; // Now we get the full path to the file NSString* fullPathToFile = [documentsDirectory stringByAppendingPathComponent:imageName]; // and then we write it out [imageData writeToFile:fullPathToFile atomically:NO]; You would repeat this for every version of the image you have. How Do I Load These Images Back Into Memory? Just look at the various UIImage initialization methods, such as +imageWithContentsOfFile: in the Apple documentation.

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• Nothing drawing on screen OpenGL with GLSL

  - by codemonkey

  I hate to be asking this kind of question here, but I am at a complete loss as to what is going wrong, so please bear with me. I am trying to render a single cube (voxel) in the center of the screen, through OpenGL with GLSL on Mac I begin by setting up everything using glut glutInit(&argc, argv); glutInitDisplayMode(GLUT_RGBA|GLUT_ALPHA|GLUT_DOUBLE|GLUT_DEPTH); glutInitWindowSize(DEFAULT_WINDOW_WIDTH, DEFAULT_WINDOW_HEIGHT); glutCreateWindow("Cubez-OSX"); glutReshapeFunc(reshape); glutDisplayFunc(render); glutIdleFunc(idle); _electricSheepEngine=new ElectricSheepEngine(DEFAULT_WINDOW_WIDTH, DEFAULT_WINDOW_HEIGHT); _electricSheepEngine->initWorld(); glutMainLoop(); Then inside the engine init camera & projection matrices: cameraPosition=glm::vec3(2,2,2); cameraTarget=glm::vec3(0,0,0); cameraUp=glm::vec3(0,0,1); glm::vec3 cameraDirection=glm::normalize(cameraPosition-cameraTarget); cameraRight=glm::cross(cameraDirection, cameraUp); cameraRight.z=0; view=glm::lookAt(cameraPosition, cameraTarget, cameraUp); lensAngle=45.0f; aspectRatio=1.0*(windowWidth/windowHeight); nearClippingPlane=0.1f; farClippingPlane=100.0f; projection=glm::perspective(lensAngle, aspectRatio, nearClippingPlane, farClippingPlane); then init shaders and check compilation and bound attributes & uniforms to be correctly bound (my previous question) These are my two shaders, vertex: #version 120 attribute vec3 position; attribute vec3 inColor; uniform mat4 mvp; varying vec3 fragColor; void main(void){ fragColor = inColor; gl_Position = mvp * vec4(position, 1.0); } and fragment: #version 120 varying vec3 fragColor; void main(void) { gl_FragColor = vec4(fragColor,1.0); } init the cube: setPosition(glm::vec3(0,0,0)); struct voxelData data[]={ //front face {{-1.0, -1.0, 1.0}, {0.0, 0.0, 1.0}}, {{ 1.0, -1.0, 1.0}, {0.0, 1.0, 1.0}}, {{ 1.0, 1.0, 1.0}, {0.0, 0.0, 1.0}}, {{-1.0, 1.0, 1.0}, {0.0, 1.0, 1.0}}, //back face {{-1.0, -1.0, -1.0}, {0.0, 0.0, 1.0}}, {{ 1.0, -1.0, -1.0}, {0.0, 1.0, 1.0}}, {{ 1.0, 1.0, -1.0}, {0.0, 0.0, 1.0}}, {{-1.0, 1.0, -1.0}, {0.0, 1.0, 1.0}} }; glGenBuffers(1, &modelVerticesBufferObject); glBindBuffer(GL_ARRAY_BUFFER, modelVerticesBufferObject); glBufferData(GL_ARRAY_BUFFER, sizeof(data), data, GL_STATIC_DRAW); glBindBuffer(GL_ARRAY_BUFFER, 0); const GLubyte indices[] = { // Front 0, 1, 2, 2, 3, 0, // Back 4, 6, 5, 4, 7, 6, // Left 2, 7, 3, 7, 6, 2, // Right 0, 4, 1, 4, 1, 5, // Top 6, 2, 1, 1, 6, 5, // Bottom 0, 3, 7, 0, 7, 4 }; glGenBuffers(1, &modelFacesBufferObject); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, modelFacesBufferObject); glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0); and then the render call: glClearColor(0.52, 0.8, 0.97, 1.0); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glEnable(GL_DEPTH_TEST); //use the shader glUseProgram(shaderProgram); //enable attributes in program glEnableVertexAttribArray(shaderAttribute_position); glEnableVertexAttribArray(shaderAttribute_color); //model matrix using model position vector glm::mat4 mvp=projection*view*voxel->getModelMatrix(); glUniformMatrix4fv(shaderAttribute_mvp, 1, GL_FALSE, glm::value_ptr(mvp)); glBindBuffer(GL_ARRAY_BUFFER, voxel->modelVerticesBufferObject); glVertexAttribPointer(shaderAttribute_position, // attribute 3, // number of elements per vertex, here (x,y) GL_FLOAT, // the type of each element GL_FALSE, // take our values as-is sizeof(struct voxelData), // coord every (sizeof) elements 0 // offset of first element ); glBindBuffer(GL_ARRAY_BUFFER, voxel->modelVerticesBufferObject); glVertexAttribPointer(shaderAttribute_color, // attribute 3, // number of colour elements per vertex, here (x,y) GL_FLOAT, // the type of each element GL_FALSE, // take our values as-is sizeof(struct voxelData), // coord every (sizeof) elements (GLvoid *)(offsetof(struct voxelData, color3D)) // offset of colour data ); //draw the model by going through its elements array glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, voxel->modelFacesBufferObject); int bufferSize; glGetBufferParameteriv(GL_ELEMENT_ARRAY_BUFFER, GL_BUFFER_SIZE, &bufferSize); glDrawElements(GL_TRIANGLES, bufferSize/sizeof(GLushort), GL_UNSIGNED_SHORT, 0); //close up the attribute in program, no more need glDisableVertexAttribArray(shaderAttribute_position); glDisableVertexAttribArray(shaderAttribute_color); but on screen all I get is the clear color :$ I generate my model matrix using: modelMatrix=glm::translate(glm::mat4(1.0), position); which in debug turns out to be for the position of (0,0,0): |1, 0, 0, 0| |0, 1, 0, 0| |0, 0, 1, 0| |0, 0, 0, 1| Sorry for such a question, I know it is annoying to look at someone's code, but I promise I have tried to debug around and figure it out as much as I can, and can't come to a solution Help a noob please? EDIT: Full source here, if anyone wants

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• Opposite Force to Apply to a Collided Rigid Body?

  - by Milo

  I'm working on the physics for my GTA2-like game so I can learn more about game physics. The collision detection and resolution are working great. I'm now just unsure how to compute the force to apply to a body after it collides with a wall. My rigid body looks like this: /our simulation object class RigidBody extends Entity { //linear private Vector2D velocity = new Vector2D(); private Vector2D forces = new Vector2D(); private float mass; private Vector2D v = new Vector2D(); //angular private float angularVelocity; private float torque; private float inertia; //graphical private Vector2D halfSize = new Vector2D(); private Bitmap image; private Matrix mat = new Matrix(); private float[] Vector2Ds = new float[2]; private Vector2D tangent = new Vector2D(); private static Vector2D worldRelVec = new Vector2D(); private static Vector2D relWorldVec = new Vector2D(); private static Vector2D pointVelVec = new Vector2D(); private static Vector2D acceleration = new Vector2D(); public RigidBody() { //set these defaults so we don't get divide by zeros mass = 1.0f; inertia = 1.0f; setLayer(LAYER_OBJECTS); } protected void rectChanged() { if(getWorld() != null) { getWorld().updateDynamic(this); } } //intialize out parameters public void initialize(Vector2D halfSize, float mass, Bitmap bitmap) { //store physical parameters this.halfSize = halfSize; this.mass = mass; image = bitmap; inertia = (1.0f / 20.0f) * (halfSize.x * halfSize.x) * (halfSize.y * halfSize.y) * mass; RectF rect = new RectF(); float scalar = 10.0f; rect.left = (int)-halfSize.x * scalar; rect.top = (int)-halfSize.y * scalar; rect.right = rect.left + (int)(halfSize.x * 2.0f * scalar); rect.bottom = rect.top + (int)(halfSize.y * 2.0f * scalar); setRect(rect); } public void setLocation(Vector2D position, float angle) { getRect().set(position.x,position.y, getWidth(), getHeight(), angle); rectChanged(); } public Vector2D getPosition() { return getRect().getCenter(); } @Override public void update(float timeStep) { doUpdate(timeStep); } public void doUpdate(float timeStep) { //integrate physics //linear acceleration.x = forces.x / mass; acceleration.y = forces.y / mass; velocity.x += (acceleration.x * timeStep); velocity.y += (acceleration.y * timeStep); //velocity = Vector2D.add(velocity, Vector2D.scalarMultiply(acceleration, timeStep)); Vector2D c = getRect().getCenter(); v.x = getRect().getCenter().getX() + (velocity.x * timeStep); v.y = getRect().getCenter().getY() + (velocity.y * timeStep); setCenter(v.x, v.y); forces.x = 0; //clear forces forces.y = 0; //angular float angAcc = torque / inertia; angularVelocity += angAcc * timeStep; setAngle(getAngle() + angularVelocity * timeStep); torque = 0; //clear torque } //take a relative Vector2D and make it a world Vector2D public Vector2D relativeToWorld(Vector2D relative) { mat.reset(); Vector2Ds[0] = relative.x; Vector2Ds[1] = relative.y; mat.postRotate(JMath.radToDeg(getAngle())); mat.mapVectors(Vector2Ds); relWorldVec.x = Vector2Ds[0]; relWorldVec.y = Vector2Ds[1]; return relWorldVec; } //take a world Vector2D and make it a relative Vector2D public Vector2D worldToRelative(Vector2D world) { mat.reset(); Vector2Ds[0] = world.x; Vector2Ds[1] = world.y; mat.postRotate(JMath.radToDeg(-getAngle())); mat.mapVectors(Vector2Ds); worldRelVec.x = Vector2Ds[0]; worldRelVec.y = Vector2Ds[1]; return worldRelVec; } //velocity of a point on body public Vector2D pointVelocity(Vector2D worldOffset) { tangent.x = -worldOffset.y; tangent.y = worldOffset.x; pointVelVec.x = (tangent.x * angularVelocity) + velocity.x; pointVelVec.y = (tangent.y * angularVelocity) + velocity.y; return pointVelVec; } public void applyForce(Vector2D worldForce, Vector2D worldOffset) { //add linear force forces.x += worldForce.x; forces.y += worldForce.y; //add associated torque torque += Vector2D.cross(worldOffset, worldForce); } @Override public void draw( GraphicsContext c) { c.drawRotatedScaledBitmap(image, getPosition().x, getPosition().y, getWidth(), getHeight(), getAngle()); } public Vector2D getVelocity() { return velocity; } public void setVelocity(Vector2D velocity) { this.velocity = velocity; } } The way it is given force is by the applyForce method, this method considers angular torque. I'm just not sure how to come up with the vectors in the case where: RigidBody hits static entity RigidBody hits other RigidBody that may or may not be in motion. Would anyone know a way (without too complex math) that I could figure out the opposite force I need to apply to the car? I know the normal it is colliding with and how deep it collided. My main goal is so that say I hit a building from the side, well the car should not just stay there, it should slowly rotate out of it if I'm more than 45 degrees. Right now when I hit a wall I only change the velocity directly which does not consider angular force. Thanks!

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• GameplayScreen does not contain a definition for GraphicsDevice

  - by Dave Voyles

  Long story short: I'm trying to intergrate my game with Microsoft's Game State Management. In doing so I've run into some errors, and the latest one is in the title. I'm not able to display my HUD for the reasons listed above. Previously, I had much of my code in my Game.cs class, but the GSM has a bit of it in Game1, and most of what you have drawn for the main screen in your GameplayScreen class, and that is what is causing confusion on my part. I've created an instance of the GameplayScreen class to be used in the HUD class (as you can see below). Before integrating with the GSM however, I created an instance of my Game class, and all worked fine. It seems that I need to define my graphics device somewhere, but I am not sure of where exactly. I've left some code below to help you understand. public class GameStateManagementGame : Microsoft.Xna.Framework.Game { #region Fields GraphicsDeviceManager graphics; ScreenManager screenManager; // Creates a new intance, which is used in the HUD class public static Game Instance; // By preloading any assets used by UI rendering, we avoid framerate glitches // when they suddenly need to be loaded in the middle of a menu transition. static readonly string[] preloadAssets = { "gradient", }; #endregion #region Initialization /// <summary> /// The main game constructor. /// </summary> public GameStateManagementGame() { Content.RootDirectory = "Content"; graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = 1280; graphics.PreferredBackBufferHeight = 720; graphics.IsFullScreen = false; graphics.ApplyChanges(); // Create the screen manager component. screenManager = new ScreenManager(this); Components.Add(screenManager); // Activate the first screens. screenManager.AddScreen(new BackgroundScreen(), null); //screenManager.AddScreen(new MainMenuScreen(), null); screenManager.AddScreen(new PressStartScreen(), null); } namespace Pong { public class HUD { public void Update(GameTime gameTime) { // Used in the Draw method titleSafeRectangle = new Rectangle (GameplayScreen.Instance.GraphicsDevice.Viewport.TitleSafeArea.X, GameplayScreen.Instance.GraphicsDevice.Viewport.TitleSafeArea.Y, GameplayScreen.Instance.GraphicsDevice.Viewport.TitleSafeArea.Width, GameplayScreen.Instance.GraphicsDevice.Viewport.TitleSafeArea.Height); } } } class GameplayScreen : GameScreen { #region Fields ContentManager content; public static GameStates gamestate; private GraphicsDeviceManager graphics; public int screenWidth; public int screenHeight; private Texture2D backgroundTexture; private SpriteBatch spriteBatch; private Menu menu; private SpriteFont arial; private HUD hud; Animation player; // Creates a new intance, which is used in the HUD class public static GameplayScreen Instance; public GameplayScreen() { TransitionOnTime = TimeSpan.FromSeconds(1.5); TransitionOffTime = TimeSpan.FromSeconds(0.5); } protected void Initialize() { lastScored = false; menu = new Menu(); resetTimer = 0; resetTimerInUse = true; ball = new Ball(content, new Vector2(screenWidth, screenHeight)); SetUpMulti(); input = new Input(); hud = new HUD(); // Places the powerup animation inside of the surrounding box // Needs to be cleaned up, instead of using hard pixel values player = new Animation(content.Load<Texture2D>(@"gfx/powerupSpriteSheet"), new Vector2(103, 44), 64, 64, 4, 5); // Used by for the Powerups random = new Random(); vec = new Vector2(100, 50); vec2 = new Vector2(100, 100); promptVec = new Vector2(50, 25); timer = 10000.0f; // Starting value for the cooldown for the powerup timer timerVector = new Vector2(10, 10); //JEP - one time creation of powerup objects playerOnePowerup = new Powerup(); playerOnePowerup.Activated += PowerupActivated; playerOnePowerup.Deactivated += PowerupDeactivated; playerTwoPowerup = new Powerup(); playerTwoPowerup.Activated += PowerupActivated; playerTwoPowerup.Deactivated += PowerupDeactivated; //JEP - moved from events since these only need set once activatedVec = new Vector2(100, 125); deactivatedVec = new Vector2(100, 150); powerupReady = false; }

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• Can't get LWJGL lighting to work

  - by Zarkonnen

  I'm trying to enable lighting in lwjgl according to the method described by NeHe and this post. However, no matter what I try, all faces of my shapes always receive the same amount of light, or, in the case of a spinning shape, the amount of lighting seems to oscillate. All faces are lit up by the same amount, which changes as the pyramid rotates. Concrete example (apologies for the length): Note how all panels are always the same brightness, but the brightness varies with the pyramid's rotation. This is using lwjgl 2.8.3 on Mac OS X. package com; import com.zarkonnen.lwjgltest.Main; import org.lwjgl.opengl.Display; import org.lwjgl.opengl.DisplayMode; import org.lwjgl.opengl.GL11; import org.newdawn.slick.opengl.Texture; import org.newdawn.slick.opengl.TextureLoader; import org.lwjgl.util.glu.*; import org.lwjgl.input.Keyboard; import java.nio.FloatBuffer; import java.nio.ByteBuffer; import java.nio.ByteOrder; /** * * @author penguin */ public class main { public static void main(String[] args) { try { Display.setDisplayMode(new DisplayMode(800, 600)); Display.setTitle("3D Pyramid"); Display.create(); } catch (Exception e) { } initGL(); float rtri = 0.0f; Texture texture = null; try { texture = TextureLoader.getTexture("png", Main.class.getResourceAsStream("tex.png")); } catch (Exception ex) { ex.printStackTrace(); } while (!Display.isCloseRequested()) { // Draw a Triangle :D GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT); GL11.glLoadIdentity(); GL11.glTranslatef(0.0f, 0.0f, -10.0f); GL11.glRotatef(rtri, 0.0f, 1.0f, 0.0f); texture.bind(); GL11.glBegin(GL11.GL_TRIANGLES); GL11.glTexCoord2f(0.0f, 1.0f); GL11.glVertex3f(0.0f, 1.0f, 0.0f); GL11.glTexCoord2f(-1.0f, -1.0f); GL11.glVertex3f(-1.0f, -1.0f, 1.0f); GL11.glTexCoord2f(1.0f, -1.0f); GL11.glVertex3f(1.0f, -1.0f, 1.0f); GL11.glTexCoord2f(0.0f, 1.0f); GL11.glVertex3f(0.0f, 1.0f, 0.0f); GL11.glTexCoord2f(-1.0f, -1.0f); GL11.glVertex3f(1.0f, -1.0f, 1.0f); GL11.glTexCoord2f(1.0f, -1.0f); GL11.glVertex3f(1.0f, -1.0f, -1.0f); GL11.glTexCoord2f(0.0f, 1.0f); GL11.glVertex3f(0.0f, 1.0f, 0.0f); GL11.glTexCoord2f(-1.0f, -1.0f); GL11.glVertex3f(-1.0f, -1.0f, -1.0f); GL11.glTexCoord2f(1.0f, -1.0f); GL11.glVertex3f(1.0f, -1.0f, -1.0f); GL11.glTexCoord2f(0.0f, 1.0f); GL11.glVertex3f(0.0f, 1.0f, 0.0f); GL11.glTexCoord2f(-1.0f, -1.0f); GL11.glVertex3f(-1.0f, -1.0f, -1.0f); GL11.glTexCoord2f(1.0f, -1.0f); GL11.glVertex3f(-1.0f, -1.0f, 1.0f); GL11.glEnd(); GL11.glBegin(GL11.GL_QUADS); GL11.glVertex3f(1.0f, -1.0f, 1.0f); GL11.glVertex3f(1.0f, -1.0f, -1.0f); GL11.glVertex3f(-1.0f, -1.0f, -1.0f); GL11.glVertex3f(-1.0f, -1.0f, 1.0f); GL11.glEnd(); Display.update(); rtri += 0.05f; // Exit-Key = ESC boolean exitPressed = Keyboard.isKeyDown(Keyboard.KEY_ESCAPE); if (exitPressed) { System.out.println("Escape was pressed!"); Display.destroy(); } } Display.destroy(); } private static void initGL() { GL11.glEnable(GL11.GL_LIGHTING); GL11.glMatrixMode(GL11.GL_PROJECTION); GL11.glLoadIdentity(); GLU.gluPerspective(45.0f, ((float) 800) / ((float) 600), 0.1f, 100.0f); GL11.glMatrixMode(GL11.GL_MODELVIEW); GL11.glLoadIdentity(); GL11.glEnable(GL11.GL_TEXTURE_2D); GL11.glShadeModel(GL11.GL_SMOOTH); GL11.glClearColor(0.0f, 0.0f, 0.0f, 0.0f); GL11.glClearDepth(1.0f); GL11.glEnable(GL11.GL_DEPTH_TEST); GL11.glDepthFunc(GL11.GL_LEQUAL); GL11.glHint(GL11.GL_PERSPECTIVE_CORRECTION_HINT, GL11.GL_NICEST); float lightAmbient[] = {0.5f, 0.5f, 0.5f, 1.0f}; // Ambient Light Values float lightDiffuse[] = {1.0f, 1.0f, 1.0f, 1.0f}; // Diffuse Light Values float lightPosition[] = {0.0f, 0.0f, 2.0f, 1.0f}; // Light Position ByteBuffer temp = ByteBuffer.allocateDirect(16); temp.order(ByteOrder.nativeOrder()); GL11.glLight(GL11.GL_LIGHT1, GL11.GL_AMBIENT, (FloatBuffer) temp.asFloatBuffer().put(lightAmbient).flip()); // Setup The Ambient Light GL11.glLight(GL11.GL_LIGHT1, GL11.GL_DIFFUSE, (FloatBuffer) temp.asFloatBuffer().put(lightDiffuse).flip()); // Setup The Diffuse Light GL11.glLight(GL11.GL_LIGHT1, GL11.GL_POSITION, (FloatBuffer) temp.asFloatBuffer().put(lightPosition).flip()); // Position The Light GL11.glEnable(GL11.GL_LIGHT1); // Enable Light One } }

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• xutility file???

  - by user574290

  Hi all. I'm trying to use c code with opencv in face detection and counting, but I cannot build the source. I am trying to compile my project and I am having a lot of problems with a line in the xutility file. the error message show that it error with xutility file. Please help me, how to solve this problem? this is my code // Include header files #include "stdafx.h" #include "cv.h" #include "highgui.h" #include <stdio.h> #include <stdlib.h> #include <string.h> #include <assert.h> #include <math.h> #include <float.h> #include <limits.h> #include <time.h> #include <ctype.h> #include <iostream> #include <fstream> #include <vector> using namespace std; #ifdef _EiC #define WIN32 #endif int countfaces=0; int numFaces = 0; int k=0 ; int list=0; char filelist[512][512]; int timeCount = 0; static CvMemStorage* storage = 0; static CvHaarClassifierCascade* cascade = 0; void detect_and_draw( IplImage* image ); void WriteInDB(); int found_face(IplImage* img,CvPoint pt1,CvPoint pt2); int load_DB(char * filename); const char* cascade_name = "C:\\Program Files\\OpenCV\\OpenCV2.1\\data\\haarcascades\\haarcascade_frontalface_alt_tree.xml"; // BEGIN NEW CODE #define WRITEVIDEO char* outputVideo = "c:\\face_counting1_tracked.avi"; //int faceCount = 0; int posBuffer = 100; int persistDuration = 10; //faces can drop out for 10 frames int timestamp = 0; float sameFaceDistThreshold = 30; //pixel distance CvPoint facePositions[100]; int facePositionsTimestamp[100]; float distance( CvPoint a, CvPoint b ) { float dist = sqrt(float ( (a.x-b.x)*(a.x-b.x) + (a.y-b.y)*(a.y-b.y) ) ); return dist; } void expirePositions() { for (int i = 0; i < posBuffer; i++) { if (facePositionsTimestamp[i] <= (timestamp - persistDuration)) //if a tracked pos is older than three frames { facePositions[i] = cvPoint(999,999); } } } void updateCounter(CvPoint center) { bool newFace = true; for(int i = 0; i < posBuffer; i++) { if (distance(center, facePositions[i]) < sameFaceDistThreshold) { facePositions[i] = center; facePositionsTimestamp[i] = timestamp; newFace = false; break; } } if(newFace) { //push out oldest tracker for(int i = 1; i < posBuffer; i++) { facePositions[i] = facePositions[i - 1]; } //put new tracked position on top of stack facePositions[0] = center; facePositionsTimestamp[0] = timestamp; countfaces++; } } void drawCounter(IplImage* image) { // Create Font char buffer[5]; CvFont font; cvInitFont(&font, CV_FONT_HERSHEY_SIMPLEX, .5, .5, 0, 1); cvPutText(image, "Faces:", cvPoint(20, 20), &font, CV_RGB(0,255,0)); cvPutText(image, itoa(countfaces, buffer, 10), cvPoint(80, 20), &font, CV_RGB(0,255,0)); } #ifdef WRITEVIDEO CvVideoWriter* videoWriter = cvCreateVideoWriter(outputVideo, -1, 30, cvSize(240, 180)); #endif //END NEW CODE int main( int argc, char** argv ) { CvCapture* capture = 0; IplImage *frame, *frame_copy = 0; int optlen = strlen("--cascade="); const char* input_name; if( argc > 1 && strncmp( argv[1], "--cascade=", optlen ) == 0 ) { cascade_name = argv[1] + optlen; input_name = argc > 2 ? argv[2] : 0; } else { cascade_name = "C:\\Program Files\\OpenCV\\OpenCV2.1\\data\\haarcascades\\haarcascade_frontalface_alt_tree.xml"; input_name = argc > 1 ? argv[1] : 0; } cascade = (CvHaarClassifierCascade*)cvLoad( cascade_name, 0, 0, 0 ); if( !cascade ) { fprintf( stderr, "ERROR: Could not load classifier cascade\n" ); fprintf( stderr, "Usage: facedetect --cascade=\"<cascade_path>\" [filename|camera_index]\n" ); return -1; } storage = cvCreateMemStorage(0); //if( !input_name || (isdigit(input_name[0]) && input_name[1] == '\0') ) // capture = cvCaptureFromCAM( !input_name ? 0 : input_name[0] - '0' ); //else capture = cvCaptureFromAVI( "c:\\face_counting1.avi" ); cvNamedWindow( "result", 1 ); if( capture ) { for(;;) { if( !cvGrabFrame( capture )) break; frame = cvRetrieveFrame( capture ); if( !frame ) break; if( !frame_copy ) frame_copy = cvCreateImage( cvSize(frame->width,frame->height), IPL_DEPTH_8U, frame->nChannels ); if( frame->origin == IPL_ORIGIN_TL ) cvCopy( frame, frame_copy, 0 ); else cvFlip( frame, frame_copy, 0 ); detect_and_draw( frame_copy ); if( cvWaitKey( 30 ) >= 0 ) break; } cvReleaseImage( &frame_copy ); cvReleaseCapture( &capture ); } else { if( !input_name || (isdigit(input_name[0]) && input_name[1] == '\0')) cvNamedWindow( "result", 1 ); const char* filename = input_name ? input_name : (char*)"lena.jpg"; IplImage* image = cvLoadImage( filename, 1 ); if( image ) { detect_and_draw( image ); cvWaitKey(0); cvReleaseImage( &image ); } else { /* assume it is a text file containing the list of the image filenames to be processed - one per line */ FILE* f = fopen( filename, "rt" ); if( f ) { char buf[1000+1]; while( fgets( buf, 1000, f ) ) { int len = (int)strlen(buf); while( len > 0 && isspace(buf[len-1]) ) len--; buf[len] = '\0'; image = cvLoadImage( buf, 1 ); if( image ) { detect_and_draw( image ); cvWaitKey(0); cvReleaseImage( &image ); } } fclose(f); } } } cvDestroyWindow("result"); #ifdef WRITEVIDEO cvReleaseVideoWriter(&videoWriter); #endif return 0; } void detect_and_draw( IplImage* img ) { static CvScalar colors[] = { {{0,0,255}}, {{0,128,255}}, {{0,255,255}}, {{0,255,0}}, {{255,128,0}}, {{255,255,0}}, {{255,0,0}}, {{255,0,255}} }; double scale = 1.3; IplImage* gray = cvCreateImage( cvSize(img->width,img->height), 8, 1 ); IplImage* small_img = cvCreateImage( cvSize( cvRound (img->width/scale), cvRound (img->height/scale)), 8, 1 ); CvPoint pt1, pt2; int i; cvCvtColor( img, gray, CV_BGR2GRAY ); cvResize( gray, small_img, CV_INTER_LINEAR ); cvEqualizeHist( small_img, small_img ); cvClearMemStorage( storage ); if( cascade ) { double t = (double)cvGetTickCount(); CvSeq* faces = cvHaarDetectObjects( small_img, cascade, storage, 1.1, 2, 0/*CV_HAAR_DO_CANNY_PRUNING*/, cvSize(30, 30) ); t = (double)cvGetTickCount() - t; printf( "detection time = %gms\n", t/((double)cvGetTickFrequency()*1000.) ); if (faces) { //To save the detected faces into separate images, here's a quick and dirty code: char filename[6]; for( i = 0; i < (faces ? faces->total : 0); i++ ) { /* CvRect* r = (CvRect*)cvGetSeqElem( faces, i ); CvPoint center; int radius; center.x = cvRound((r->x + r->width*0.5)*scale); center.y = cvRound((r->y + r->height*0.5)*scale); radius = cvRound((r->width + r->height)*0.25*scale); cvCircle( img, center, radius, colors[i%8], 3, 8, 0 );*/ // Create a new rectangle for drawing the face CvRect* r = (CvRect*)cvGetSeqElem( faces, i ); // Find the dimensions of the face,and scale it if necessary pt1.x = r->x*scale; pt2.x = (r->x+r->width)*scale; pt1.y = r->y*scale; pt2.y = (r->y+r->height)*scale; // Draw the rectangle in the input image cvRectangle( img, pt1, pt2, CV_RGB(255,0,0), 3, 8, 0 ); CvPoint center; int radius; center.x = cvRound((r->x + r->width*0.5)*scale); center.y = cvRound((r->y + r->height*0.5)*scale); radius = cvRound((r->width + r->height)*0.25*scale); cvCircle( img, center, radius, CV_RGB(255,0,0), 3, 8, 0 ); //update counter updateCounter(center); int y=found_face(img,pt1,pt2); if(y==0) countfaces++; }//end for printf("Number of detected faces: %d\t",countfaces); }//end if //delete old track positions from facePositions array expirePositions(); timestamp++; //draw counter drawCounter(img); #ifdef WRITEVIDEO cvWriteFrame(videoWriter, img); #endif cvShowImage( "result", img ); cvDestroyWindow("Result"); cvReleaseImage( &gray ); cvReleaseImage( &small_img ); }//end if } //end void int found_face(IplImage* img,CvPoint pt1,CvPoint pt2) { /*if (faces) {*/ CvSeq* faces = cvHaarDetectObjects( img, cascade, storage, 1.1, 2, CV_HAAR_DO_CANNY_PRUNING, cvSize(40, 40) ); int i=0; char filename[512]; for( i = 0; i < (faces ? faces->total : 0); i++ ) {//int scale = 1, i=0; //i=iface; //char filename[512]; /* extract the rectanlges only */ // CvRect face_rect = *(CvRect*)cvGetSeqElem( faces, i); CvRect face_rect = *(CvRect*)cvGetSeqElem( faces, i); //IplImage* gray_img = cvCreateImage( cvGetSize(img), IPL_DEPTH_8U, 1 ); IplImage* clone = cvCreateImage (cvSize(img->width, img->height), IPL_DEPTH_8U, img->nChannels ); IplImage* gray = cvCreateImage (cvSize(img->width, img->height), IPL_DEPTH_8U, 1 ); cvCopy (img, clone, 0); cvNamedWindow ("ROI", CV_WINDOW_AUTOSIZE); cvCvtColor( clone, gray, CV_RGB2GRAY ); face_rect.x = pt1.x; face_rect.y = pt1.y; face_rect.width = abs(pt1.x - pt2.x); face_rect.height = abs(pt1.y - pt2.y); cvSetImageROI ( gray, face_rect); //// * rectangle = cvGetImageROI ( clone ); face_rect = cvGetImageROI ( gray ); cvShowImage ("ROI", gray); k++; char *name=0; name=(char*) calloc(512, 1); sprintf(name, "Image%d.pgm", k); cvSaveImage(name, gray); //////////////// for(int j=0;j<512;j++) filelist[list][j]=name[j]; list++; WriteInDB(); //int found=SIFT("result.txt",name); cvResetImageROI( gray ); //return found; return 0; // }//end if }//end for }//end void void WriteInDB() { ofstream myfile; myfile.open ("result.txt"); for(int i=0;i<512;i++) { if(strcmp(filelist[i],"")!=0) myfile << filelist[i]<<"\n"; } myfile.close(); } Error 3 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int Error 8 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int Error 13 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\program files\microsoft visual studio 9.0\vc\include\xutility 766 Error 18 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\program files\microsoft visual studio 9.0\vc\include\xutility 768 Error 23 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\program files\microsoft visual studio 9.0\vc\include\xutility 769 Error 10 error C2868: 'std::iterator_traits<_Iter>::value_type' : illegal syntax for using-declaration; expected qualified-name c:\program files\microsoft visual studio 9.0\vc\include\xutility 765 Error 25 error C2868: 'std::iterator_traits<_Iter>::reference' : illegal syntax for using-declaration; expected qualified-name c:\program files\microsoft visual studio 9.0\vc\include\xutility 769 Error 20 error C2868: 'std::iterator_traits<_Iter>::pointer' : illegal syntax for using-declaration; expected qualified-name c:\program files\microsoft visual studio 9.0\vc\include\xutility 768 Error 5 error C2868: 'std::iterator_traits<_Iter>::iterator_category' : illegal syntax for using-declaration; expected qualified-name c:\program files\microsoft visual studio 9.0\vc\include\xutility 764 Error 15 error C2868: 'std::iterator_traits<_Iter>::difference_type' : illegal syntax for using-declaration; expected qualified-name c:\program files\microsoft visual studio 9.0\vc\include\xutility 766 Error 9 error C2602: 'std::iterator_traits<_Iter>::value_type' is not a member of a base class of 'std::iterator_traits<_Iter>' c:\program files\microsoft visual studio 9.0\vc\include\xutility 765 Error 24 error C2602: 'std::iterator_traits<_Iter>::reference' is not a member of a base class of 'std::iterator_traits<_Iter>' c:\program files\microsoft visual studio 9.0\vc\include\xutility 769 Error 19 error C2602: 'std::iterator_traits<_Iter>::pointer' is not a member of a base class of 'std::iterator_traits<_Iter>' c:\program files\microsoft visual studio 9.0\vc\include\xutility 768 Error 4 error C2602: 'std::iterator_traits<_Iter>::iterator_category' is not a member of a base class of 'std::iterator_traits<_Iter>' c:\program files\microsoft visual studio 9.0\vc\include\xutility 764 Error 14 error C2602: 'std::iterator_traits<_Iter>::difference_type' is not a member of a base class of 'std::iterator_traits<_Iter>' c:\program files\microsoft visual studio 9.0\vc\include\xutility 766 Error 7 error C2146: syntax error : missing ';' before identifier 'value_type' c:\program files\microsoft visual studio 9.0\vc\include\xutility 765 Error 22 error C2146: syntax error : missing ';' before identifier 'reference' c:\program files\microsoft visual studio 9.0\vc\include\xutility 769 Error 17 error C2146: syntax error : missing ';' before identifier 'pointer' c:\program files\microsoft visual studio 9.0\vc\include\xutility 768 Error 2 error C2146: syntax error : missing ';' before identifier 'iterator_category' c:\program files\microsoft visual studio 9.0\vc\include\xutility 764 Error 12 error C2146: syntax error : missing ';' before identifier 'difference_type' c:\program files\microsoft visual studio 9.0\vc\include\xutility 766 Error 6 error C2039: 'value_type' : is not a member of 'CvPoint' c:\program files\microsoft visual studio 9.0\vc\include\xutility 765 Error 21 error C2039: 'reference' : is not a member of 'CvPoint' c:\program files\microsoft visual studio 9.0\vc\include\xutility 769 Error 16 error C2039: 'pointer' : is not a member of 'CvPoint' c:\program files\microsoft visual studio 9.0\vc\include\xutility 768 Error 1 error C2039: 'iterator_category' : is not a member of 'CvPoint' c:\program files\microsoft visual studio 9.0\vc\include\xutility 764 Error 11 error C2039: 'difference_type' : is not a member of 'CvPoint' c:\program files\microsoft visual studio 9.0\vc\include\xutility 766

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• Stumbling Through: Visual Studio 2010 (Part II)

  I would now like to expand a little on what I stumbled through in part I of my Visual Studio 2010 post and touch on a few other features of VS 2010.  Specifically, I want to generate some code based off of an Entity Framework model and tie it up to an actual data source.  Im not going to take the easy way and tie to a SQL Server data source, though, I will tie it to an XML data file instead.  Why?  Well, why not?  This is purely for learning, there are probably much better ways to get strongly-typed classes around XML but it will force us to go down a path less travelled and maybe learn a few things along the way.  Once we get this XML data and the means to interact with it, I will revisit data binding to this data in a WPF form and see if I cant get reading, adding, deleting, and updating working smoothly with minimal code.  To begin, I will use what was learned in the first part of this blog topic and draw out a data model for the MFL (My Football League) - I dont want the NFL to come down and sue me for using their name in this totally football-related article.  The data model looks as follows, with Teams having Players, and Players having a position and statistics for each season they played: Note that when making the associations between these entities, I was given the option to create the foreign key but I only chose to select this option for the association between Player and Position.  The reason for this is that I am picturing the XML that will contain this data to look somewhat like this: <MFL> <Position/> <Position/> <Position/> <Team>     <Player>         <Statistic/>     </Player> </Team> </MFL> Statistic will be under its associated Player node, and Player will be under its associated Team node no need to have an Id to reference it if we know it will always fall under its parent.  Position, however, is more of a lookup value that will not have any hierarchical relationship to the player.  In fact, the Position data itself may be in a completely different xml file (something Id like to play around with), so in any case, a player will need to reference the position by its Id. So now that we have a simple data model laid out, I would like to generate two things based on it:  A class for each entity with properties corresponding to each entity property An IO class with methods to get data for each entity, either all instances, by Id or by parent. Now my experience with code generation in the past has consisted of writing up little apps that use the code dom directly to regenerate code on demand (or using tools like CodeSmith).  Surely, there has got to be a more fun way to do this given that we are using the Entity Framework which already has built-in code generation for SQL Server support.  Lets start with that built-in stuff to give us a base to work off of.  Right click anywhere in the canvas of our model and select Add Code Generation Item: So just adding that code item seemed to do quite a bit towards what I was intending: It apparently generated a class for each entity, but also a whole ton more.  I mean a TON more.  Way too much complicated code was generated now that code is likely to be a black box anyway so it shouldnt matter, but we need to understand how to make this work the way we want it to work, so lets get ready to do some stumbling through that text template (tt) file. When I open the .tt file that was generated, right off the bat I realize there is going to be trouble there is no color coding, no intellisense no nothing!  That is going to make stumbling through more like groping blindly in the dark while handcuffed and hopping on one foot, which was one of the alternate titles I was considering for this blog.  Thankfully, the community comes to my rescue and I wont have to cast my mind back to the glory days of coding in VI (look it up, kids).  Using the Extension Manager (Available under the Tools menu), I did a quick search for tt editor in the Online Gallery and quickly found the Tangible T4 Editor: Downloading and installing this was a breeze, and after doing so I got some color coding and intellisense while editing the tt files.  If you will be doing any customizing of tt files, I highly recommend installing this extension.  Next, well see if that is enough help for us to tweak that tt file to do the kind of code generation that we wantDid you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Not getting desired results with SSAO implementation

  - by user1294203

  After having implemented deferred rendering, I tried my luck with a SSAO implementation using this Tutorial. Unfortunately, I'm not getting anything that looks like SSAO, you can see my result below. You can see there is some weird pattern forming and there is no occlusion shading where there needs to be (i.e. in between the objects and on the ground). The shaders I implemented follow: #VS #version 330 core uniform mat4 invProjMatrix; layout(location = 0) in vec3 in_Position; layout(location = 2) in vec2 in_TexCoord; noperspective out vec2 pass_TexCoord; smooth out vec3 viewRay; void main(void){ pass_TexCoord = in_TexCoord; viewRay = (invProjMatrix * vec4(in_Position, 1.0)).xyz; gl_Position = vec4(in_Position, 1.0); } #FS #version 330 core uniform sampler2D DepthMap; uniform sampler2D NormalMap; uniform sampler2D noise; uniform vec2 projAB; uniform ivec3 noiseScale_kernelSize; uniform vec3 kernel[16]; uniform float RADIUS; uniform mat4 projectionMatrix; noperspective in vec2 pass_TexCoord; smooth in vec3 viewRay; layout(location = 0) out float out_AO; vec3 CalcPosition(void){ float depth = texture(DepthMap, pass_TexCoord).r; float linearDepth = projAB.y / (depth - projAB.x); vec3 ray = normalize(viewRay); ray = ray / ray.z; return linearDepth * ray; } mat3 CalcRMatrix(vec3 normal, vec2 texcoord){ ivec2 noiseScale = noiseScale_kernelSize.xy; vec3 rvec = texture(noise, texcoord * noiseScale).xyz; vec3 tangent = normalize(rvec - normal * dot(rvec, normal)); vec3 bitangent = cross(normal, tangent); return mat3(tangent, bitangent, normal); } void main(void){ vec2 TexCoord = pass_TexCoord; vec3 Position = CalcPosition(); vec3 Normal = normalize(texture(NormalMap, TexCoord).xyz); mat3 RotationMatrix = CalcRMatrix(Normal, TexCoord); int kernelSize = noiseScale_kernelSize.z; float occlusion = 0.0; for(int i = 0; i < kernelSize; i++){ // Get sample position vec3 sample = RotationMatrix * kernel[i]; sample = sample * RADIUS + Position; // Project and bias sample position to get its texture coordinates vec4 offset = projectionMatrix * vec4(sample, 1.0); offset.xy /= offset.w; offset.xy = offset.xy * 0.5 + 0.5; // Get sample depth float sample_depth = texture(DepthMap, offset.xy).r; float linearDepth = projAB.y / (sample_depth - projAB.x); if(abs(Position.z - linearDepth ) < RADIUS){ occlusion += (linearDepth <= sample.z) ? 1.0 : 0.0; } } out_AO = 1.0 - (occlusion / kernelSize); } I draw a full screen quad and pass Depth and Normal textures. Normals are in RGBA16F with the alpha channel reserved for the AO factor in the blur pass. I store depth in a non linear Depth buffer (32F) and recover the linear depth using: float linearDepth = projAB.y / (depth - projAB.x); where projAB.y is calculated as: and projAB.x as: These are derived from the glm::perspective(gluperspective) matrix. z_n and z_f are the near and far clip distance. As described in the link I posted on the top, the method creates samples in a hemisphere with higher distribution close to the center. It then uses random vectors from a texture to rotate the hemisphere randomly around the Z direction and finally orients it along the normal at the given pixel. Since the result is noisy, a blur pass follows the SSAO pass. Anyway, my position reconstruction doesn't seem to be wrong since I also tried doing the same but with the position passed from a texture instead of being reconstructed. I also tried playing with the Radius, noise texture size and number of samples and with different kinds of texture formats, with no luck. For some reason when changing the Radius, nothing changes. Does anyone have any suggestions? What could be going wrong?

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• creating a pre-menu level select screen

  - by Ephiras

  Hi I am working on creating a tower Defence java applet game and have come to a road block about implementing a title screen that i can select the level and difficulty of the rest of the game. my title screen class is called Menu. from this menu class i need to pass in many different variables into my Main class. i have used different classes before and know how to run them and such. but if both classes extend applet and each has its individual graphics method how can i run things from Main even though it was created in Menu. what i essentially want to do is run the Menu class withits action listeners and graphics until a Difficulty button has been selected, run the main class (which 100% works without having to have the Menu class) and pretty much terminate Menu so that i cannot go back to it, do not see its buttons or graphics menus. can i run one applet annd when i choose a button close that one and launch the other one? IF you would like to download the full project you can find it here, i had to comment out all the code that wasn't working my Menu class import java.awt.*; import java.awt.event.*; import java.applet.*; public class Menu extends Applet implements ActionListener{ Button bEasy,bMed,bHard; Main m; public void init(){ bEasy= new Button("Easy"); bEasy.setBounds(140,200,100,50); add(bEasy); bMed = new Button("Medium");bMed.setBounds(280,200,100,50); add(bMed); bHard= new Button("Hard");bHard.setBounds(420,200,100,50); add(bHard); setLayout(null); } public void actionPerformed(ActionEvent e){ Main m = new Main(20,10,3000,mapMed);//break; switch (e.getSource()){ case bEasy: Main m = new Main(6000,20,"levels/levelEasy.png");break;//enimies tower money world case bMed: Main m = new Main(4000,15,"levels/levelMed.png");break; case bHard: Main m = new Main(2000,10,"levels/levelEasy.png");break; default: break; } } public void paint(){ //m.draw(g) } } and here is my main class initialising code. import java.awt.*; import java.awt.event.*; import java.applet.*; import java.io.IOException; public class Main extends Applet implements Runnable, MouseListener, MouseMotionListener, ActionListener{ Button startButton, UpgRange, UpgDamage; //set up the buttons Color roadCol,startCol,finCol,selGrass,selRoad; //set up the colors Enemy e[][]; Tower t[]; Image towerpic,backpic,roadpic,levelPic; private Image i; private Graphics doubleG; //here is the world 0=grass 1=road 2=start 3=end int world[][],eStartX,eStartY; boolean drawMouse,gameEnd; static boolean start=false; static int gridLength=15; static int round=0; int Mx,My,timer=1500; static int sqrSize=31; int towers=0,towerSelected=-10; static int castleHealth=2000; String levelPath; //choose the level Easy Med or Hard int maxEnemy[] = {5,7,12,20,30,15,50,30,40,60};//number of enimies per round int maxTowers=15;//maximum number of towers allowed static int money =2000,damPrice=600,ranPrice=350,towerPrice=700; //money = the intial ammount of money you start of with //damPrice is the price to increase the damage of a tower //ranPrice is the price to increase the range of a tower public void main(int cH,int mT,int mo,int dP,int rP,int tP,String path,int[] mE)//constructor 1 castleHealth=cH; maxTowers=mT; money=mo; damPrice=dP; ranPrice=rP; towerPrice=tP; String levelPath=path; maxEnemy = mE; buildLevel(); } public void main(int cH,int mT,String path)//basic constructor castleHealth=cH; maxTowers=mT; String levelPath=path; maxEnemy = mE; buildLevel(); } public void init(){ setSize(sqrSize*15+200,sqrSize*15);//set the size of the screen roadCol = new Color(255,216,0);//set the colors for the different objects startCol = new Color(0,38,255); finCol = new Color(255,0,0); selRoad = new Color(242,204,155);//selColor is the color of something when your mouse hovers over it selGrass = new Color(0,190,0); roadpic = getImage(getDocumentBase(),"images/road.jpg"); towerpic = getImage(getDocumentBase(),"images/tower.png"); backpic = getImage(getDocumentBase(),"images/grass.jpg"); levelPic = getImage(getDocumentBase(),"images/level.jpg"); e= new Enemy[maxEnemy.length][];//activates all of the enimies for (int r=0;r<e.length;r++) e[r] = new Enemy[maxEnemy[r]]; t= new Tower[maxTowers]; for (int i=0;i<t.length;i++) t[i]= new Tower();//activates all the towers for (int i=0;i<e.length; i++)//sets all of the enimies starting co ordinates for (int j=0;j<e[i].length;j++) e[i][j] = new Enemy(eStartX,eStartY,world); initButtons();//initialise all the buttons addMouseMotionListener(this); addMouseListener(this); }

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• Trying to detect collision between two polygons using Separating Axis Theorem

  - by Holly

  The only collision experience i've had was with simple rectangles, i wanted to find something that would allow me to define polygonal areas for collision and have been trying to make sense of SAT using these two links Though i'm a bit iffy with the math for the most part i feel like i understand the theory! Except my implementation somewhere down the line must be off as: (excuse the hideous font) As mentioned above i have defined a CollisionPolygon class where most of my theory is implemented and then have a helper class called Vect which was meant to be for Vectors but has also been used to contain a vertex given that both just have two float values. I've tried stepping through the function and inspecting the values to solve things but given so many axes and vectors and new math to work out as i go i'm struggling to find the erroneous calculation(s) and would really appreciate any help. Apologies if this is not suitable as a question! CollisionPolygon.java: package biz.hireholly.gameplay; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import biz.hireholly.gameplay.Types.Vect; public class CollisionPolygon { Paint paint; private Vect[] vertices; private Vect[] separationAxes; CollisionPolygon(Vect[] vertices){ this.vertices = vertices; //compute edges and separations axes separationAxes = new Vect[vertices.length]; for (int i = 0; i < vertices.length; i++) { // get the current vertex Vect p1 = vertices[i]; // get the next vertex Vect p2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; // subtract the two to get the edge vector Vect edge = p1.subtract(p2); // get either perpendicular vector Vect normal = edge.perp(); // the perp method is just (x, y) => (-y, x) or (y, -x) separationAxes[i] = normal; } paint = new Paint(); paint.setColor(Color.RED); } public void draw(Canvas c, int xPos, int yPos){ for (int i = 0; i < vertices.length; i++) { Vect v1 = vertices[i]; Vect v2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; c.drawLine( xPos + v1.x, yPos + v1.y, xPos + v2.x, yPos + v2.y, paint); } } /* consider changing to a static function */ public boolean intersects(CollisionPolygon p){ // loop over this polygons separation exes for (Vect axis : separationAxes) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // loop over the other polygons separation axes Vect[] sepAxesOther = p.getSeparationAxes(); for (Vect axis : sepAxesOther) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // if we get here then we know that every axis had overlap on it // so we can guarantee an intersection return true; } /* Note projections wont actually be acurate if the axes aren't normalised * but that's not necessary since we just need a boolean return from our * intersects not a Minimum Translation Vector. */ private Vect minMaxProjection(Vect axis) { float min = axis.dot(vertices[0]); float max = min; for (int i = 1; i < vertices.length; i++) { float p = axis.dot(vertices[i]); if (p < min) { min = p; } else if (p > max) { max = p; } } Vect minMaxProj = new Vect(min, max); return minMaxProj; } public Vect[] getSeparationAxes() { return separationAxes; } public Vect[] getVertices() { return vertices; } } Vect.java: package biz.hireholly.gameplay.Types; /* NOTE: Can also be used to hold vertices! Projections, coordinates ect */ public class Vect{ public float x; public float y; public Vect(float x, float y){ this.x = x; this.y = y; } public Vect perp() { return new Vect(-y, x); } public Vect subtract(Vect other) { return new Vect(x - other.x, y - other.y); } public boolean overlap(Vect other) { if( other.x <= y || other.y >= x){ return true; } return false; } /* used specifically for my SAT implementation which i'm figuring out as i go, * references for later.. * http://www.gamedev.net/page/resources/_/technical/game-programming/2d-rotated-rectangle-collision-r2604 * http://www.codezealot.org/archives/55 */ public float scalarDotProjection(Vect other) { //multiplier = dot product / length^2 float multiplier = dot(other) / (x*x + y*y); //to get the x/y of the projection vector multiply by x/y of axis float projX = multiplier * x; float projY = multiplier * y; //we want to return the dot product of the projection, it's meaningless but useful in our SAT case return dot(new Vect(projX,projY)); } public float dot(Vect other){ return (other.x*x + other.y*y); } }

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• Windows for IoT, continued

  - by Valter Minute

  Originally posted on: http://geekswithblogs.net/WindowsEmbeddedCookbook/archive/2014/08/05/windows-for-iot-continued.aspxI received many interesting feedbacks on my previous blog post and I tried to find some time to do some additional tests. Bert Kleinschmidt pointed out that pins 2,3 and 10 of the Galileo are connected directly to the SOC, while pin 13, the one used for the sample sketch is controlled via an I2C I/O expander. I changed my code to use pin 2 instead of 13 (just changing the variable assignment at the beginning of the code) and latency was greatly reduced. Now each pulse lasts for 1.44ms, 44% more than the expected time, but ways better that the result we got using pin 13. I also used SetThreadPriority to increase the priority of the thread that was running the sketch to THREAD_PRIORITY_HIGHEST but that didn't change the results. When I was using the I2C-controlled pin I tried the same and the timings got ways worse (increasing more than 10 times) and so I did not commented on that part, wanting to investigate the issua a bit more in detail. It seems that increasing the priority of the application thread impacts negatively the I2C communication. I tried to use also the Linux-based implementation (using a different Galileo board since the one provided by MS seems to use a different firmware) and the results of running the sample blink sketch modified to use pin 2 and blink the led for 1ms are similar to those we got on the same board running Windows. Here the difference between expected time and measured time is worse, getting around 3.2ms instead of 1 (320% compared to 150% using Windows but far from the 100.1% we got with the 8-bit Arduino). Both systems were not under load during the test, maybe loading some applications that use part of the CPU time would make those timings even less reliable, but I think that those numbers are enough to draw some conclusions. It may not be worth running a full OS if what you need is Arduino compatibility. The Arduino UNO is probably the best Arduino you can find to perform this kind of development. The Galileo running the Linux-based stack or running Windows for IoT is targeted to be a platform for "Internet of Things" devices, whatever that means. At the moment I don't see the "I" part of IoT. We have low level interfaces (SPI, I2C, the GPIO pins) that can be used to connect sensors but the support for connectivity is limited and the amount of work required to deliver some data to the cloud (using a secure HTTP request or a message queuing system like APMQS or MQTT) is still big and the rich OS underneath seems to not provide any help doing that.Why should I use sockets and can't access all the high level connectivity features we have on "full" Windows?I know that it's possible to use some third party libraries, try to build them using the Windows For IoT SDK etc. but this means re-inventing the wheel every time and can also lead to some IP concerns if used for products meant to be closed-source. I hope that MS and Intel (and others) will focus less on the "coolness" of running (some) Arduino sketches and more on providing a better platform to people that really want to design devices that leverage internet connectivity and the cloud processing power to deliver better products and services. Providing a reliable set of connectivity services would be a great start. Providing support for .NET would be even better, leaving native code available for hardware access etc. I know that those components may require additional storage and memory etc. So making the OS componentizable (or, at least, provide a way to install additional components) would be a great way to let developers pick the parts of the system they need to develop their solution, knowing that they will integrate well together. I can understand that the Arduino and Raspberry Pi* success may have attracted the attention of marketing departments worldwide and almost any new development board those days is promoted as "XXX response to Arduino" or "YYYY alternative to Raspberry Pi", but this is misleading and prevents companies from focusing on how to deliver good products and how to integrate "IoT" features with their existing offer to provide, at the end, a better product or service to their customers. Marketing is important, but can't decide the key features of a product (the OS) that is going to be used to develop full products for end customers integrating it with hardware and application software. I really like the "hackable" nature of open-source devices and like to see that companies are getting more and more open in releasing information, providing "hackable" devices and supporting developers with documentation, good samples etc. On the other side being able to run a sketch designed for an 8 bit microcontroller on a full-featured application processor may sound cool and an easy upgrade path for people that just experimented with sensors etc. on Arduino but it's not, in my humble opinion, the main path to follow for people who want to deliver real products.   *Shameless self-promotion: if you are looking for a good book in Italian about the Raspberry Pi , try mine: http://www.amazon.it/Raspberry-Pi-alluso-Digital-LifeStyle-ebook/dp/B00GYY3OKO

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• how to retain the animated position in opengl es 2.0

  - by Arun AC

  I am doing frame based animation for 300 frames in opengl es 2.0 I want a rectangle to translate by +200 pixels in X axis and also scaled up by double (2 units) in the first 100 frames Then, the animated rectangle has to stay there for the next 100 frames. Then, I want the same animated rectangle to translate by +200 pixels in X axis and also scaled down by half (0.5 units) in the last 100 frames. I am using simple linear interpolation to calculate the delta-animation value for each frame. Pseudo code: The below drawFrame() is executed for 300 times (300 frames) in a loop. float RectMVMatrix[4][4] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1 }; // identity matrix int totalframes = 300; float translate-delta; // interpolated translation value for each frame float scale-delta; // interpolated scale value for each frame // The usual code for draw is: void drawFrame(int iCurrentFrame) { // mySetIdentity(RectMVMatrix); // comment this line to retain the animated position. mytranslate(RectMVMatrix, translate-delta, X_AXIS); // to translate the mv matrix in x axis by translate-delta value myscale(RectMVMatrix, scale-delta); // to scale the mv matrix by scale-delta value ... // opengl calls glDrawArrays(...); eglswapbuffers(...); } The above code will work fine for first 100 frames. in order to retain the animated rectangle during the frames 101 to 200, i removed the "mySetIdentity(RectMVMatrix);" in the above drawFrame(). Now on entering the drawFrame() for the 2nd frame, the RectMVMatrix will have the animated value of first frame e.g. RectMVMatrix[4][4] = { 1.01, 0, 0, 2, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1 };// 2 pixels translation and 1.01 units scaling after first frame This RectMVMatrix is used for mytranslate() in 2nd frame. The translate function will affect the value of "RectMVMatrix[0][0]". Thus translation affects the scaling values also. Eventually output is getting wrong. How to retain the animated position without affecting the current ModelView matrix? =========================================== I got the solution... Thanks to Sergio. I created separate matrices for translation and scaling. e.g.CurrentTranslateMatrix[4][4], CurrentScaleMatrix[4][4]. Then for every frame, I reset 'CurrentTranslateMatrix' to identity and call mytranslate( CurrentTranslateMatrix, translate-delta, X_AXIS) function. I reset 'CurrentScaleMatrix' to identity and call myscale(CurrentScaleMatrix, scale-delta) function. Then, I multiplied these 'CurrentTranslateMatrix' and 'CurrentScaleMatrix' to get the final 'RectMVMatrix' Matrix for the frame. Pseudo Code: float RectMVMatrix[4][4] = {0}; float CurrentTranslateMatrix[4][4] = {0}; float CurrentScaleMatrix[4][4] = {0}; int iTotalFrames = 300; int iAnimationFrames = 100; int iTranslate_X = 200.0f; // in pixels float fScale_X = 2.0f; float scaleDelta; float translateDelta_X; void DrawRect(int iTotalFrames) { mySetIdentity(RectMVMatrix); for (int i = 0; i< iTotalFrames; i++) { DrawFrame(int iCurrentFrame); } } void getInterpolatedValue(int iStartFrame, int iEndFrame, int iTotalFrame, int iCurrentFrame, float *scaleDelta, float *translateDelta_X) { float fDelta = float ( (iCurrentFrame - iStartFrame) / (iEndFrame - iStartFrame)) float fStartX = 0.0f; float fEndX = ConvertPixelsToOpenGLUnit(iTranslate_X); *translateDelta_X = fStartX + fDelta * (fEndX - fStartX); float fStartScaleX = 1.0f; float fEndScaleX = fScale_X; *scaleDelta = fStartScaleX + fDelta * (fEndScaleX - fStartScaleX); } void DrawFrame(int iCurrentFrame) { getInterpolatedValue(0, iAnimationFrames, iTotalFrames, iCurrentFrame, &scaleDelta, &translateDelta_X) mySetIdentity(CurrentTranslateMatrix); myTranslate(RectMVMatrix, translateDelta_X, X_AXIS); // to translate the mv matrix in x axis by translate-delta value mySetIdentity(CurrentScaleMatrix); myScale(RectMVMatrix, scaleDelta); // to scale the mv matrix by scale-delta value myMultiplyMatrix(RectMVMatrix, CurrentTranslateMatrix, CurrentScaleMatrix);// RectMVMatrix = CurrentTranslateMatrix*CurrentScaleMatrix; ... // opengl calls glDrawArrays(...); eglswapbuffers(...); } I maintained this 'RectMVMatrix' value, if there is no animation for the current frame (e.g. 101th frame onwards). Thanks, Arun AC

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• Error in my Separating Axis Theorem collision code

  - by Holly

  The only collision experience i've had was with simple rectangles, i wanted to find something that would allow me to define polygonal areas for collision and have been trying to make sense of SAT using these two links Though i'm a bit iffy with the math for the most part i feel like i understand the theory! Except my implementation somewhere down the line must be off as: (excuse the hideous font) As mentioned above i have defined a CollisionPolygon class where most of my theory is implemented and then have a helper class called Vect which was meant to be for Vectors but has also been used to contain a vertex given that both just have two float values. I've tried stepping through the function and inspecting the values to solve things but given so many axes and vectors and new math to work out as i go i'm struggling to find the erroneous calculation(s) and would really appreciate any help. Apologies if this is not suitable as a question! CollisionPolygon.java: package biz.hireholly.gameplay; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import biz.hireholly.gameplay.Types.Vect; public class CollisionPolygon { Paint paint; private Vect[] vertices; private Vect[] separationAxes; int x; int y; CollisionPolygon(Vect[] vertices){ this.vertices = vertices; //compute edges and separations axes separationAxes = new Vect[vertices.length]; for (int i = 0; i < vertices.length; i++) { // get the current vertex Vect p1 = vertices[i]; // get the next vertex Vect p2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; // subtract the two to get the edge vector Vect edge = p1.subtract(p2); // get either perpendicular vector Vect normal = edge.perp(); // the perp method is just (x, y) => (-y, x) or (y, -x) separationAxes[i] = normal; } paint = new Paint(); paint.setColor(Color.RED); } public void draw(Canvas c, int xPos, int yPos){ for (int i = 0; i < vertices.length; i++) { Vect v1 = vertices[i]; Vect v2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; c.drawLine( xPos + v1.x, yPos + v1.y, xPos + v2.x, yPos + v2.y, paint); } } public void update(int xPos, int yPos){ x = xPos; y = yPos; } /* consider changing to a static function */ public boolean intersects(CollisionPolygon p){ // loop over this polygons separation exes for (Vect axis : separationAxes) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // loop over the other polygons separation axes Vect[] sepAxesOther = p.getSeparationAxes(); for (Vect axis : sepAxesOther) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // if we get here then we know that every axis had overlap on it // so we can guarantee an intersection return true; } /* Note projections wont actually be acurate if the axes aren't normalised * but that's not necessary since we just need a boolean return from our * intersects not a Minimum Translation Vector. */ private Vect minMaxProjection(Vect axis) { float min = axis.dot(new Vect(vertices[0].x+x, vertices[0].y+y)); float max = min; for (int i = 1; i < vertices.length; i++) { float p = axis.dot(new Vect(vertices[i].x+x, vertices[i].y+y)); if (p < min) { min = p; } else if (p > max) { max = p; } } Vect minMaxProj = new Vect(min, max); return minMaxProj; } public Vect[] getSeparationAxes() { return separationAxes; } public Vect[] getVertices() { return vertices; } } Vect.java: package biz.hireholly.gameplay.Types; /* NOTE: Can also be used to hold vertices! Projections, coordinates ect */ public class Vect{ public float x; public float y; public Vect(float x, float y){ this.x = x; this.y = y; } public Vect perp() { return new Vect(-y, x); } public Vect subtract(Vect other) { return new Vect(x - other.x, y - other.y); } public boolean overlap(Vect other) { if(y > other.x && other.y > x){ return true; } return false; } /* used specifically for my SAT implementation which i'm figuring out as i go, * references for later.. * http://www.gamedev.net/page/resources/_/technical/game-programming/2d-rotated-rectangle-collision-r2604 * http://www.codezealot.org/archives/55 */ public float scalarDotProjection(Vect other) { //multiplier = dot product / length^2 float multiplier = dot(other) / (x*x + y*y); //to get the x/y of the projection vector multiply by x/y of axis float projX = multiplier * x; float projY = multiplier * y; //we want to return the dot product of the projection, it's meaningless but useful in our SAT case return dot(new Vect(projX,projY)); } public float dot(Vect other){ return (other.x*x + other.y*y); } }

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• Collision Error

  - by Manji

  I am having trouble with collision detection part of the game. I am using touch events to fire the gun as you will see in the video. Note, the android icon is a temporary graphic for the bullets When ever the user touches (represented by clicks in the video)the bullet appears and kills random sprites. As you can see it never touches the sprites it kills or kill the sprites it does touch. My Question is How do I fix it, so that the sprite dies when the bullet hits it? Collision Code snippet: //Handles Collision private void CheckCollisions(){ synchronized(mSurfaceHolder){ for (int i = sprites.size() - 1; i >= 0; i--){ Sprite sprite = sprites.get(i); if(sprite.isCollision(bullet)){ sprites.remove(sprite); mScore++; if(sprites.size() == 0){ mLevel = mLevel +1; currentLevel++; initLevel(); } break; } } } } Sprite Class Code Snippet: //bounding box left<right and top>bottom int left ; int right ; int top ; int bottom ; public boolean isCollision(Beam other) { // TODO Auto-generated method stub if(this.left>other.right || other.left<other.right)return false; if(this.bottom>other.top || other.bottom<other.top)return false; return true; } EDIT 1: Sprite Class: public class Sprite { // direction = 0 up, 1 left, 2 down, 3 right, // animation = 3 back, 1 left, 0 front, 2 right int[] DIRECTION_TO_ANIMATION_MAP = { 3, 1, 0, 2 }; private static final int BMP_ROWS = 4; private static final int BMP_COLUMNS = 3; private static final int MAX_SPEED = 5; private HitmanView gameView; private Bitmap bmp; private int x; private int y; private int xSpeed; private int ySpeed; private int currentFrame = 0; private int width; private int height; //bounding box left<right and top>bottom int left ; int right ; int top ; int bottom ; public Sprite(HitmanView gameView, Bitmap bmp) { this.width = bmp.getWidth() / BMP_COLUMNS; this.height = bmp.getHeight() / BMP_ROWS; this.gameView = gameView; this.bmp = bmp; Random rnd = new Random(); x = rnd.nextInt(gameView.getWidth() - width); y = rnd.nextInt(gameView.getHeight() - height); xSpeed = rnd.nextInt(MAX_SPEED * 2) - MAX_SPEED; ySpeed = rnd.nextInt(MAX_SPEED * 2) - MAX_SPEED; } private void update() { if (x >= gameView.getWidth() - width - xSpeed || x + xSpeed <= 0) { xSpeed = -xSpeed; } x = x + xSpeed; if (y >= gameView.getHeight() - height - ySpeed || y + ySpeed <= 0) { ySpeed = -ySpeed; } y = y + ySpeed; currentFrame = ++currentFrame % BMP_COLUMNS; } public void onDraw(Canvas canvas) { update(); int srcX = currentFrame * width; int srcY = getAnimationRow() * height; Rect src = new Rect(srcX, srcY, srcX + width, srcY + height); Rect dst = new Rect(x, y, x + width, y + height); canvas.drawBitmap(bmp, src, dst, null); } private int getAnimationRow() { double dirDouble = (Math.atan2(xSpeed, ySpeed) / (Math.PI / 2) + 2); int direction = (int) Math.round(dirDouble) % BMP_ROWS; return DIRECTION_TO_ANIMATION_MAP[direction]; } public boolean isCollision(float x2, float y2){ return x2 > x && x2 < x + width && y2 > y && y2 < y + height; } public boolean isCollision(Beam other) { // TODO Auto-generated method stub if(this.left>other.right || other.left<other.right)return false; if(this.bottom>other.top || other.bottom<other.top)return false; return true; } } Bullet Class: public class Bullet { int mX; int mY; private Bitmap mBitmap; //bounding box left<right and top>bottom int left ; int right ; int top ; int bottom ; public Bullet (Bitmap mBitmap){ this.mBitmap = mBitmap; } public void draw(Canvas canvas, int mX, int mY) { this.mX = mX; this.mY = mY; canvas.drawBitmap(mBitmap, mX, mY, null); } }

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• Applications: The Mathematics of Movement, Part 3

  - by TechTwaddle

  Previously: Part 1, Part 2 As promised in the previous post, this post will cover two variations of the marble move program. The first one, Infinite Move, keeps the marble moving towards the click point, rebounding it off the screen edges and changing its direction when the user clicks again. The second version, Finite Move, is the same as first except that the marble does not move forever. It moves towards the click point, rebounds off the screen edges and slowly comes to rest. The amount of time that it moves depends on the distance between the click point and marble. Infinite Move This case is simple (actually both cases are simple). In this case all we need is the direction information which is exactly what the unit vector stores. So when the user clicks, you calculate the unit vector towards the click point and then keep updating the marbles position like crazy. And, of course, there is no stop condition. There’s a little more additional code in the bounds checking conditions. Whenever the marble goes off the screen boundaries, we need to reverse its direction.  Here is the code for mouse up event and UpdatePosition() method, //stores the unit vector double unitX = 0, unitY = 0; double speed = 6; //speed times the unit vector double incrX = 0, incrY = 0; private void Form1_MouseUp(object sender, MouseEventArgs e) {     double x = e.X - marble1.x;     double y = e.Y - marble1.y;     //calculate distance between click point and current marble position     double lenSqrd = x * x + y * y;     double len = Math.Sqrt(lenSqrd);     //unit vector along the same direction (from marble towards click point)     unitX = x / len;     unitY = y / len;     timer1.Enabled = true; } private void UpdatePosition() {     //amount by which to increment marble position     incrX = speed * unitX;     incrY = speed * unitY;     marble1.x += incrX;     marble1.y += incrY;     //check for bounds     if ((int)marble1.x < MinX + marbleWidth / 2)     {         marble1.x = MinX + marbleWidth / 2;         unitX *= -1;     }     else if ((int)marble1.x > (MaxX - marbleWidth / 2))     {         marble1.x = MaxX - marbleWidth / 2;         unitX *= -1;     }     if ((int)marble1.y < MinY + marbleHeight / 2)     {         marble1.y = MinY + marbleHeight / 2;         unitY *= -1;     }     else if ((int)marble1.y > (MaxY - marbleHeight / 2))     {         marble1.y = MaxY - marbleHeight / 2;         unitY *= -1;     } } So whenever the user clicks we calculate the unit vector along that direction and also the amount by which the marble position needs to be incremented. The speed in this case is fixed at 6. You can experiment with different values. And under bounds checking, whenever the marble position goes out of bounds along the x or y direction we reverse the direction of the unit vector along that direction. Here’s a video of it running;   Finite Move The code for finite move is almost exactly same as that of Infinite Move, except for the difference that the speed is not fixed and there is an end condition, so the marble comes to rest after a while. Code follows, //unit vector along the direction of click point double unitX = 0, unitY = 0; //speed of the marble double speed = 0; private void Form1_MouseUp(object sender, MouseEventArgs e) {     double x = 0, y = 0;     double lengthSqrd = 0, length = 0;     x = e.X - marble1.x;     y = e.Y - marble1.y;     lengthSqrd = x * x + y * y;     //length in pixels (between click point and current marble pos)     length = Math.Sqrt(lengthSqrd);     //unit vector along the same direction as vector(x, y)     unitX = x / length;     unitY = y / length;     speed = length / 12;     timer1.Enabled = true; } private void UpdatePosition() {     marble1.x += speed * unitX;     marble1.y += speed * unitY;     //check for bounds     if ((int)marble1.x < MinX + marbleWidth / 2)     {         marble1.x = MinX + marbleWidth / 2;         unitX *= -1;     }     else if ((int)marble1.x > (MaxX - marbleWidth / 2))     {         marble1.x = MaxX - marbleWidth / 2;         unitX *= -1;     }     if ((int)marble1.y < MinY + marbleHeight / 2)     {         marble1.y = MinY + marbleHeight / 2;         unitY *= -1;     }     else if ((int)marble1.y > (MaxY - marbleHeight / 2))     {         marble1.y = MaxY - marbleHeight / 2;         unitY *= -1;     }     //reduce speed by 3% in every loop     speed = speed * 0.97f;     if ((int)speed <= 0)     {         timer1.Enabled = false;     } } So the only difference is that the speed is calculated as a function of length when the mouse up event occurs. Again, this can be experimented with. Bounds checking is same as before. In the update and draw cycle, we reduce the speed by 3% in every cycle. Since speed is calculated as a function of length, speed = length/12, the amount of time it takes speed to reach zero is directly proportional to length. Note that the speed is in ‘pixels per 40ms’ because the timeout value of the timer is 40ms.  The readability can be improved by representing speed in ‘pixels per second’. This would require you to add some more calculations to the code, which I leave out as an exercise. Here’s a video of this second version,

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• Issue with a point coordinates, which creates an unwanted triangle

  - by Paul

  I would like to connect the points from the red path, to the y-axis in blue. I figured out that the problem with my triangles came from the first point (V0) : it is not located where it should be. In the console, it says its location is at 0,0, but in the emulator, it is not. The code : for(int i = 1; i < 2; i++) { CCLOG(@"_polyVertices[i-1].x : %f, _polyVertices[i-1].y : %f", _polyVertices[i-1].x, _polyVertices[i-1].y); CCLOG(@"_polyVertices[i].x : %f, _polyVertices[i].y : %f", _polyVertices[i].x, _polyVertices[i].y); ccDrawLine(_polyVertices[i-1], _polyVertices[i]); } The output : _polyVertices[i-1].x : 0.000000, _polyVertices[i-1].y : 0.000000 _polyVertices[i].x : 50.000000, _polyVertices[i].y : 0.000000 And the result : (the layer goes up, i could not take the screenshot before the layer started to go up, but the first red point starts at y=0) : Then it creates an unwanted triangle when the code continues : Would you have any idea about this? (So to force the first blue point to start at 0,0, and not at 50,0 as it seems to be now) Here is the code : - (void)generatePath{ float x = 50; //first red point float y = 0; for(int i = 0; i < kMaxKeyPoints+1; i++) { if (i<3){ _hillKeyPoints[i] = CGPointMake(x, y); x = 150 + (random() % (int) 30); y += -40; } else if(i<20){ //going right _hillKeyPoints[i] = CGPointMake(x, y); x += (random() % (int) 30); y += -40; } else if(i<25){ //stabilize _hillKeyPoints[i] = CGPointMake(x, y); x = 150 + (random() % (int) 30); y += -40; } else if(i<30){ //going left _hillKeyPoints[i] = CGPointMake(x, y); //x -= (random() % (int) 10); x = 150 + (random() % (int) 30); y += -40; } else { //back to normal _hillKeyPoints[i] = CGPointMake(x, y); x = 150 + (random() % (int) 30); y += -40; } } } -(void)generatePolygons{ static int prevFromKeyPointI = -1; static int prevToKeyPointI = -1; // key points interval for drawing while (_hillKeyPoints[_fromKeyPointI].y > -_offsetY+winSizeTop) { _fromKeyPointI++; } while (_hillKeyPoints[_toKeyPointI].y > -_offsetY-winSizeBottom) { _toKeyPointI++; } if (prevFromKeyPointI != _fromKeyPointI || prevToKeyPointI != _toKeyPointI) { _nPolyVertices = 0; float x1 = 0; int keyPoints = _fromKeyPointI; for (int i=_fromKeyPointI; i<_toKeyPointI; i++){ //V0: at (0,0) _polyVertices[_nPolyVertices] = CGPointMake(x1, y1); //first blue point _polyTexCoords[_nPolyVertices++] = CGPointMake(x1, y1); //V1: to the first "point" _polyVertices[_nPolyVertices] = CGPointMake(_hillKeyPoints[keyPoints].x, _hillKeyPoints[keyPoints].y); _polyTexCoords[_nPolyVertices++] = CGPointMake(_hillKeyPoints[keyPoints].x, _hillKeyPoints[keyPoints].y); keyPoints++; //from point at index 0 to 1 //V2, same y as point n°2: _polyVertices[_nPolyVertices] = CGPointMake(0, _hillKeyPoints[keyPoints].y); _polyTexCoords[_nPolyVertices++] = CGPointMake(0, _hillKeyPoints[keyPoints].y); //V1 again _polyVertices[_nPolyVertices] = _polyVertices[_nPolyVertices-2]; _polyTexCoords[_nPolyVertices++] = _polyVertices[_nPolyVertices-2]; //V2 again _polyVertices[_nPolyVertices] = _polyVertices[_nPolyVertices-2]; _polyTexCoords[_nPolyVertices++] = _polyVertices[_nPolyVertices-2]; //CCLOG(@"_nPolyVertices V2 again : %i", _nPolyVertices); //V3 = same x,y as point at index 1 _polyVertices[_nPolyVertices] = CGPointMake(_hillKeyPoints[keyPoints].x, _hillKeyPoints[keyPoints].y); _polyTexCoords[_nPolyVertices] = CGPointMake(_hillKeyPoints[keyPoints].x, _hillKeyPoints[keyPoints].y); y1 = _polyVertices[_nPolyVertices].y; _nPolyVertices++; } prevFromKeyPointI = _fromKeyPointI; prevToKeyPointI = _toKeyPointI; } } - (void) draw { //RED glColor4f(1, 1, 1, 1); for(int i = MAX(_fromKeyPointI, 1); i <= _toKeyPointI; ++i) { glColor4f(1.0, 0, 0, 1.0); ccDrawLine(_hillKeyPoints[i-1], _hillKeyPoints[i]); } //BLUE glColor4f(0, 0, 1, 1); for(int i = 1; i < 2; i++) { CCLOG(@"_polyVertices[i-1].x : %f, _polyVertices[i-1].y : %f", _polyVertices[i-1].x, _polyVertices[i-1].y); CCLOG(@"_polyVertices[i].x : %f, _polyVertices[i].y : %f", _polyVertices[i].x, _polyVertices[i].y); ccDrawLine(_polyVertices[i-1], _polyVertices[i]); } } Thanks

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• Data Binding to Attached Properties

  - by Chris Gardner

  Originally posted on: http://geekswithblogs.net/freestylecoding/archive/2013/06/14/data-binding-to-attached-properties.aspx When I was working on my C#/XAML game framework, I discovered I wanted to try to data bind my sprites to background objects. That way, I could update my objects and the draw functionality would take care of the work for me. After a little experimenting and web searching, it appeared this concept was an impossible dream. Of course, when has that ever stopped me? In my typical way, I started to massively dive down the rabbit hole. I created a sprite on a canvas, and I bound it to a background object. <Canvas Name="GameField" Background="Black"> <Image Name="PlayerStrite" Source="Assets/Ship.png" Width="50" Height="50" Canvas.Left="{Binding X}" Canvas.Top="{Binding Y}"/> </Canvas> Now, we wire the UI item to the background item. public MainPage() { this.InitializeComponent(); this.Loaded += StartGame; }   void StartGame( object sender, RoutedEventArgs e ) { BindingPlayer _Player = new BindingPlayer(); _Player.X = Window.Current.Bounds.Height - PlayerSprite.Height; _Player.X = ( Window.Current.Bounds.Width - PlayerSprite.Width ) / 2.0; } Of course, now we need to actually have our background object. public class BindingPlayer : INotifyPropertyChanged { private double m_X; public double X { get { return m_X; } set { m_X = value; NotifyPropertyChanged(); } }   private double m_Y; public double Y { get { return m_Y; } set { m_Y = value; NotifyPropertyChanged(); } }   public event PropertyChangedEventHandler PropertyChanged; protected void NotifyPropertyChanged( [CallerMemberName] string p_PropertyName = null ) { if( PropertyChanged != null ) PropertyChanged( this, new PropertyChangedEventArgs( p_PropertyName ) ); } } I fired this baby up, and my sprite was correctly positioned on the screen. Maybe the sky wasn't falling after all. Wouldn't it be great if that was the case? I created some code to allow me to move the sprite, but nothing happened. This seems odd. So, I start debugging the application and stepping through code. Everything appears to be working. Time to dig a little deeper. After much profanity was spewed, I stumbled upon a breakthrough. The code only looked like it was working. What was really happening is that there was an exception being thrown in the background thread that I never saw. Apparently, the key call was the one to PropertyChanged. If PropertyChanged is not called on the UI thread, the UI thread ignores the call. Actually, it throws an exception and the background thread silently crashes. Of course, you'll never see this unless you're looking REALLY carefully. This seemed to be a simple problem. I just need to marshal this to the UI thread. Unfortunately, this object has no knowledge of this mythical UI Thread in which we speak. So, I had to pull the UI Thread out of thin air. Let's change our PropertyChanged call to look this. public event PropertyChangedEventHandler PropertyChanged; protected void NotifyPropertyChanged( [CallerMemberName] string p_PropertyName = null ) { if( PropertyChanged != null ) Windows.ApplicationModel.Core.CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync( Windows.UI.Core.CoreDispatcherPriority.Normal, new Windows.UI.Core.DispatchedHandler( () => { PropertyChanged( this, new PropertyChangedEventArgs( p_PropertyName ) ); } ) ); } Now, we raised our notification on the UI thread. Everything is fine, people are happy, and the world moves on. You may have noticed that I didn't await my call to the dispatcher. This was intentional. If I am trying to update a slew of sprites, I don't want thread being hung while I wait my turn. Thus, I send the message and move on. It is worth nothing that this is NOT the most efficient way to do this for game programming. We'll get to that in another blog post. However, it is perfectly acceptable for a business app that is running a background task that would like to notify the UI thread of progress on a periodic basis. It is worth noting that this code was written for a Windows Store App. You can do the same thing with WP8 and WPF. The call to the marshaler changes, but it is the same idea.

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• Managing text-maps in a 2D array on to be painted on HTML5 Canvas

  - by weka

  So, I'm making a HTML5 RPG just for fun. The map is a <canvas> (512px width, 352px height | 16 tiles across, 11 tiles top to bottom). I want to know if there's a more efficient way to paint the <canvas>. Here's how I have it right now. How tiles are loaded and painted on map The map is being painted by tiles (32x32) using the Image() piece. The image files are loaded through a simple for loop and put into an array called tiles[] to be PAINTED on using drawImage(). First, we load the tiles... and here's how it's being done: // SET UP THE & DRAW THE MAP TILES tiles = []; var loadedImagesCount = 0; for (x = 0; x <= NUM_OF_TILES; x++) { var imageObj = new Image(); // new instance for each image imageObj.src = "js/tiles/t" + x + ".png"; imageObj.onload = function () { console.log("Added tile ... " + loadedImagesCount); loadedImagesCount++; if (loadedImagesCount == NUM_OF_TILES) { // Onces all tiles are loaded ... // We paint the map for (y = 0; y <= 15; y++) { for (x = 0; x <= 10; x++) { theX = x * 32; theY = y * 32; context.drawImage(tiles[5], theY, theX, 32, 32); } } } }; tiles.push(imageObj); } Naturally, when a player starts a game it loads the map they last left off. But for here, it an all-grass map. Right now, the maps use 2D arrays. Here's an example map. [[4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 1, 1, 1, 1], [1, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 1, 1, 1, 1, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 1, 13, 13, 1, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 1, 13, 13, 1, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 1, 13, 13, 1, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 1, 1, 1, 1, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 13, 13, 13, 1, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 13, 13, 11, 11, 11, 13, 13, 13, 13, 13, 13, 13, 1], [13, 13, 13, 1, 1, 1, 1, 1, 1, 1, 13, 13, 13, 13, 13, 1], [1, 1, 1, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 1, 1, 1]]; I get different maps using a simple if structure. Once the 2d array above is return, the corresponding number in each array will be painted according to Image() stored inside tile[]. Then drawImage() will occur and paint according to the x and y and times it by 32 to paint on the correct x-y coordinate. How multiple map switching occurs With my game, maps have five things to keep track of: currentID, leftID, rightID, upID, and bottomID. currentID: The current ID of the map you are on. leftID: What ID of currentID to load when you exit on the left of current map. rightID: What ID of currentID to load when you exit on the right of current map. downID: What ID of currentID to load when you exit on the bottom of current map. upID: What ID of currentID to load when you exit on the top of current map. Something to note: If either leftID, rightID, upID, or bottomID are NOT specific, that means they are a 0. That means they cannot leave that side of the map. It is merely an invisible blockade. So, once a person exits a side of the map, depending on where they exited... for example if they exited on the bottom, bottomID will the number of the map to load and thus be painted on the map. Here's a representational .GIF to help you better visualize: As you can see, sooner or later, with many maps I will be dealing with many IDs. And that can possibly get a little confusing and hectic. The obvious pros is that it load 176 tiles at a time, refresh a small 512x352 canvas, and handles one map at time. The con is that the MAP ids, when dealing with many maps, may get confusing at times. My question Is this an efficient way to store maps (given the usage of tiles), or is there a better way to handle maps? I was thinking along the lines of a giant map. The map-size is big and it's all one 2D array. The viewport, however, is still 512x352 pixels. Here's another .gif I made (for this question) to help visualize: Sorry if you cannot understand my English. Please ask anything you have trouble understanding. Hopefully, I made it clear. Thanks.

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• Speakers, Please Check Your Time

  - by AjarnMark

  Woodrow Wilson was once asked how long it would take him to prepare for a 10 minute speech. He replied "Two weeks". He was then asked how long it would take for a 1 hour speech. "One week", he replied. 2 hour speech? "I'm ready right now," he replied.  Whether that is a true story or an urban legend, I don’t really know, but either way, it is a poignant reminder for all speakers, and particularly apropos this week leading up to the PASS Community Summit. (Cross-posted to the PASS Professional Development Virtual Chapter blog #PASSProfDev.) What’s the point of that story?  Simply this…if you have plenty of time to do your presentation, you don’t need to prepare much because it is easy to throw in more and more material to stretch out to your allotted time.  But if you are on a tight time constraint, then it will take significant preparation to distill your talk down to only the essential points. I have attended seven of the last eight North American Summit events, and every one of them has been fantastic.  The speakers are great, the material is timely and relevant, and the networking opportunities are awesome.  And every year, there is one little thing that just bugs me…speakers going over their allotted time.  Why does it bother me so?  Well, if you look at a typical schedule for a Summit, you’ll see that there are six or more sessions going on at the same time, and only 15 minutes to move from one to another.  If you’re trying to maximize your training dollar by attending something during every session time slot, and you don’t want to be the last guy trying to squeeze into the middle of the row, then those 15 minutes can be critical.  All the more so if you need to stop and use the bathroom or if you have to hike to the opposite end of the convention center.  It is really a bad position to find yourself having to choose between learning the last key points of Speaker A who is going over time, and getting over to Speaker B on time so you don’t miss her key opening remarks. And frankly, I think it is just rude.  Yes, the speakers are the function, after all they are bringing the content that the rest of us are paying to learn.  But it is also an honor to be given the opportunity to speak at a conference like this, and no one speaker is so important that the conference would be a disaster without him.  Speakers know when they submit their abstract, long before the conference, how much time they will have.  It has been the same pattern at the Summit for at least the last eight years.  Program Sessions are 75 minutes long.  Some speakers who have a good track record, and meet other qualifying criteria, are extended an invitation to present a Spotlight Session which is 90 minutes (a 20% increase).  So there really is no excuse.  It’s not like you were promised a 2-hour segment and then discovered when you got here that it was only 75 minutes.  In fact, it’s not like PASS advertised 90-minute sessions for everyone and then a select few were cut back to only 75.  As a speaker, you know well before you get here which type of session you are doing and how long it is, so as a professional, you should plan accordingly. Now you might think that this only happens to rookies, but I’ll tell you that some of the worst offenders are big-name veterans who draw huge attendance numbers for their sessions.  Some attendees blow this off as, “Hey, it’s so-and-so, and I’d stay here for hours and listen to him/her talk.”  To which I would reply, “Then they should have submitted for a pre- or post-conference day-long seminar instead, but don’t try to squeeze your day-long talk into a 90-minute session.”  Now I don’t really believe that these speakers are being malicious or just selfishly trying to extend their time in the spotlight.  I think that most of them are merely being undisciplined and did not trim their presentation sufficiently, or allowed themselves to get off-track (often in a generous attempt to help someone in the audience with a question or problem that really should have been noted for further discussion after the session). So here is my recommendation…my plea, even.  TRIM THE FAT!  Now.  Before it’s too late.  Before you even get on the airplane, take a long, hard look at your presentation and eliminate some of the points that you originally thought you had to make, but in reality are not truly crucial to your main topic.  Delete a few slides.  Test your demos and have them already scripted rather than typing them during your talk.  It is better to cut out too much and end up with plenty of time at the end for Questions & Answers.  And you can always keep some notes on the stuff that you cut out so that you could fill it back in at the end as bonus material if you really do end up with a whole bunch of time on your hands.  But I don’t think you will.  And if you do, that will look even better to the audience as it will look like you’re giving them something extra that not every audience gets.  And they will thank you for that.

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• Undeclared Scope in Rock Paper Scissors Simple Game

  - by Rianelle

  #include <iostream> #include <string> #include <cstdlib> #include <ctime> using namespace std; bool win; int winnings; int draws; int loses; string comChoice; string playerChoice; void winGame () { cout << "You won! Play again?" <<endl; cout << "Type y/n" <<endl; char x; cin >> x; if (x == 'y') { beginGame(); } else if ('n'){ cout << "Game Stopped." <<endl; cout << "Number of Draws: " <<draws << endl; cout << "Number of Loses: " <<loses << endl; cout << "Number of Wins: " << winnings << endl; win = true; } } void drawGame (){ ++draws; cout << "Draw! Try again" << endl; return; } void lose () { cout << "You lose! Try again?" <<endl; cout << "Type y/n" <<endl; char feedback; cin >> feedback; if (feedback == 'y') { beginGame(); } else if ('n'){ cout << "Game Stopped." <<endl; cout << "Number of Draws: " <<draws << endl; cout << "Number of Loses: " <<loses << endl; cout << "Number of Wins: " << winnings << endl; } } void beginGame() { cout << "Welcome to the Rock, Paper and Scissors Game!" <<endl; cout << "Let's begin. Type <rock, paper, scissors> for your choice!" <<endl; cin >> playerChoice; srand(time(0)); int randomizer = 1+(rand()%3); if (randomizer == 1) comChoice = "rock"; if (randomizer == 2) comChoice = "paper"; if (randomizer == 3) comChoice = "scissors"; do { if (playerChoice == comChoice) { drawGame(); } if (playerChoice == "rock" && comChoice == "paper") ++loses; lose(); if (playerChoice == "rock" && comChoice == "scissors") ++winnings; winGame(); if (playerChoice == "paper" && comChoice == "rock") ++winnings; winGame(); if (playerChoice == "paper" && comChoice == "scissors") ++loses; lose(); if (playerChoice == "scissors" && comChoice == "rock") ++loses; lose(); if (playerChoice == "scissors" && comChoice == "paper") ++winnings; winGame(); }while (win != true); } int main () { beginGame(); return 0; }

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