Search Results

Search found 7220 results on 289 pages for 'graph algorithm'.

Page 55/289 | < Previous Page | 51 52 53 54 55 56 57 58 59 60 61 62 | Next Page >

Open Graph & Rails not retrieving object's URL

- by Fred

I'm using Rails to try and add an action for an object both defined for my app on the open graph. I am using an :after_filter in my controller to call the following after session#create: @graph.put_connections('me', 'workkout:complete', :session => url_for([@plan, @session])) I am getting the following back from Facebook: {"error":{"type":"Exception","message":"Could not retrieve data from URL.","code":1660002}} I have checked that the correct URL is passed to put_connections, and when I visit this URL using Facebook's Lint tool, everything is correct. I can't understand why this isn't working, my only thought is that Facebook is hitting the URL moments before rails has generated the object? - not sure if that's even possible though. Can anyone shed any light on this?

Read the article
Getting RPXNow and Facebook Open Graph to Play Nicely

- by ramon.tayag

A requirement to use the RPXNow is to set your Facebook application's connect url to http://mydomain.rpxnow.com. I was just trying to implement Facebook's Open Graph and I see that it tells you to set the Base Domain to the domain that will contain the app_id. However, Facebook does not allow these two domains to look different. When I try to set the base url to mydomain.com, I get this error: Validation failed. Base Domain is not valid. Connect URL must be derived from your Base Domain. Should I create two apps - one for use with RPXNow, and another for use with Open Graph? If not, what should I do? Thanks

Read the article
Resources for how to design graph/charts well

- by wesgarrison

One of my projects needs to show users where they rank in certain calculations. I inherited the graph structure from the previous programmer and had to leave it alone while I worked on other parts of the site. It's time to make the graphs more meaningful, so I'm looking for books/websites/etc about graphs. (Not graph theory!) Charts that convey comparisons at a glance. Everyone suggests The Visual Display of Quantitative Information by Edward Tufte and that's spot on for what I'm looking for, so anything related to that would be great. Naturally, personal experience about what to do or not would be helpful as well.

Read the article
MS Access MSChart.Graph.8 not printing

- by Tanj

Software: Microsoft Access 2007 SP2 Database File Version: Access 2000 I have an access program that I inherited from a previous employee. It uses forms for reports and since I don't have much experience in access I have continued to do this. I have created a copy of the program for another project and modified it to suit. I am having trouble getting more then one chart to print. All the charts display in form view, they all have the same properties (excepting data, position, etc.) For some reason they are not printing. They don't even show up in the print preview. I am thinking it must be something with the graphs themselves as they sometimes lose all information. I have to open the graphs in edit mode and change the data source from column to row and back again so that it gets redrawn. (Refresh doesn't fix it) So right now I don't even have a clue as to where to look so ideas are welcome. Edit #1 It seems to be a problem with linking to an unbound form. Subform Field Linker: Can't build a link between unbound forms. The query for the main form is SELECT tTest.ixTest, tMotorTypes.ixMotorType, tMotorTypes.asMotorType, tMotorTypes.fDeprecated, tTestType.asTest, tTest.asSerialNum, tTest.asOrderNum, tTest.asFrameNum, tTest.asRotorNum, tTest.asOperator, tTest.iStation, tTest.dtTestDate, tTest.ixTestType FROM tMotorTypes INNER JOIN (tTestType INNER JOIN tTest ON tTestType.ixTestType=tTest.ixTestType) ON tMotorTypes.ixMotorType=tTest.ixMotorType; The query for the chart is: SELECT qGraphRSTTemperatures.Frequency, qGraphRSTTemperatures.[Drive End], qGraphRSTTemperatures.[Non Drive End], qGraphRSTTemperatures.[Air In], qGraphRSTTemperatures.Core FROM qGraphRSTTemperatures ORDER BY qGraphRSTTemperatures.ixTemperature; Query qGraphRSTTemperatures: SELECT tElectricalData.dblFrequency AS Frequency, tTemperatures.dblDrvEnd AS [Drive End], tTemperatures.dblNonDrvEnd AS [Non Drive End], tTemperatures.dblAirIn AS [Air In], tTemperatures.dblCore AS Core, tSubTest.ixTest, tTemperatures.ixTemperature FROM (tSubTest INNER JOIN tElectricalData ON tSubTest.ixSubTest = tElectricalData.ixSubTest) LEFT JOIN tTemperatures ON tElectricalData.ixElectrical = tTemperatures.ixElectrical WHERE (((tSubTest.ixSubTestType)=5)) ORDER BY tSubTest.ixTest, tTemperatures.ixTemperature; So how come, in the form view it shows the graph with the correct data when linked thus: Child field: ixTest Master field: ixTest but won't print the graph. The graph will print if I remove the links, but then I have all the data from chart query as it is not limited by ixTest. edit #2 It seems to be a data retrieval/rendering issue in printing. Is there anything in printing that changes the context of records with respect to parent/child relationships?

Read the article
Pruning data for better viewing on loglog graph - Matlab

- by Geodesic

Hi Guys, just wondering if anyone has any ideas about an issue I'm having. I have a fair amount of data that needs to be displayed on one graph. Two theoretical lines that are bold and solid are displayed on top, then 10 experimental data sets that converge to these lines are graphed, each using a different identifier (eg the + or o or a square etc). These graphs are on a log scale that goes up to 1e6. The first few decades of the graph (< 1e3) look fine, but as all the datasets converge ( 1e3) it's really difficult to see what data is what. There's over 1000 data points points per decade which I can prune linearly to an extent, but if I do this too much the lower end of the graph will suffer in resolution. What I'd like to do is prune logarithmically, strongest at the high end, working back to 0. My question is: how can I get a logarithmically scaled index vector rather than a linear one? My initial assumption was that as my data is lenear I could just use a linear index to prune, which lead to something like this (but for all decades): //%grab indicies per decade ind12 = find(y >= 1e1 & y <= 1e2); indlow = find(y < 1e2); indhigh = find(y > 1e4); ind23 = find(y >+ 1e2 & y <= 1e3); ind34 = find(y >+ 1e3 & y <= 1e4); //%We want ind12 indexes in this decade, find spacing tot23 = round(length(ind23)/length(ind12)); tot34 = round(length(ind34)/length(ind12)); //%grab ones to keep ind23keep = ind23(1):tot23:ind23(end); ind34keep = ind34(1):tot34:ind34(end); indnew = [indlow' ind23keep ind34keep indhigh']; loglog(x(indnew), y(indnew)); But this causes the prune to behave in a jumpy fashion obviously. Each decade has the number of points that I'd like, but as it's a linear distribution, the points tend to be clumped at the high end of the decade on the log scale. Any ideas on how I can do this?

Read the article
Why does this Quicksort work?

- by IVlad

I find this Quicksort partitioning approach confusing and wrong, yet it seems to work. I am referring to this pseudocode. Note: they also have a C implementation at the end of the article, but it's very different from their pseudocode, so I don't care about that. I have also written it in C like this, trying to stay true to the pseudocode as much as possible, even if that means doing some weird C stuff: #include <stdio.h> int partition(int a[], int p, int r) { int x = a[p]; int i = p - 1; int j = r + 1; while (1) { do j = j - 1; while (!(a[j] <= x)); do i = i + 1; while (!(a[i] >= x)); if (i < j) { int t = a[i]; a[i] = a[j]; a[j] = t; } else { for (i = 1; i <= a[0]; ++i) printf("%d ", a[i]); printf("- %d\n", j); return j; } } } int main() { int a[100] = //{8, 6,10,13,15,8,3,2,12}; {7, 7, 6, 2, 3, 8, 4, 1}; partition(a, 1, a[0]); return 0; } If you run this, you'll get the following output: 1 6 2 3 4 8 7 - 5 However, this is wrong, isn't it? Clearly a[5] does not have all the values before it lower than it, since a[2] = 6 > a[5] = 4. Not to mention that 7 is supposed to be the pivot (the initial a[p]) and yet its position is both incorrect and lost. The following partition algorithm is taken from wikipedia: int partition2(int a[], int p, int r) { int x = a[r]; int store = p; for (int i = p; i < r; ++i) { if (a[i] <= x) { int t = a[i]; a[i] = a[store]; a[store] = t; ++store; } } int t = a[r]; a[r] = a[store]; a[store] = t; for (int i = 1; i <= a[0]; ++i) printf("%d ", a[i]); printf("- %d\n", store); return store; } And produces this output: 1 6 2 3 8 4 7 - 1 Which is a correct result in my opinion: the pivot (a[r] = a[7]) has reached its final position. However, if I use the initial partitioning function in the following algorithm: void Quicksort(int a[], int p, int r) { if (p < r) { int q = partition(a, p, r); // initial partitioning function Quicksort(a, p, q); Quicksort(a, q + 1, r); // I'm pretty sure q + r was a typo, it doesn't work with q + r. } } ... it seems to be a correct sorting algorithm. I tested it out on a lot of random inputs, including all 0-1 arrays of length 20. I have also tried using this partition function for a selection algorithm, in which it failed to produce correct results. It seems to work and it's even very fast as part of the quicksort algorithm however. So my questions are: Can anyone post an example on which the algorithm DOESN'T work? If not, why does it work, since the partitioning part seems to be wrong? Is this another partitioning approach that I don't know about?

Read the article
Graph database for .NET

- by Antonello

I've been designing an application, based on .NET/Mono framework, which should make an heavy use of the shortest-path in a graph theories and I would like to use a native solution to traverse the nodes of the graph, instead of implementing surrogate solutions which would be hardly maintainable and would massively affect performances. I've found an application which would be perfect for my scope: neo4j. Unfortunately, this application is purely written in Java code and it's not portable to .NET, because of the massive differences between the two architectures. Is anyone out there knows if is it there any port of neo4j or a similar solution for .NET?

Read the article
change attributes of SVG graph without refresh

- by Mike Hudak

Hello, I have a simple SVG graph generated by GraphViz: <?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">   <svg width="138pt" height="168pt" viewBox="0.00 0.00 138.00 168.00" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <g id="graph1" class="graph" transform="scale(1 1) rotate(0) translate(4 164)"> <title>G</title> <polygon fill="white" stroke="white" points="-4,5 -4,-164 135,-164 135,5 -4,5"/>  <g id="node1" class="node"><title>Node1</title> <a xlink:href="http://localhost/viz/applet.php" xlink:title="Internet"> <image xlink:href="images/cloud.png" width="130px" height="77px" preserveAspectRatio="xMinYMin meet" x="0" y="-159.5"/> <text text-anchor="middle" x="65" y="-116.4" font-family="Times New Roman,serif" font-size="14.00">'.$Internet.'</text> </a> </g>  <g id="node2" class="node"><title>Node2</title> <a xlink:href="http://localhost/viz/applet.php"> <image xlink:href="images/file server.png" width="44px" height="45px" preserveAspectRatio="xMinYMin meet" x="43" y="-45.5"/> </a> </g>  <g id="edge2" class="edge"><title>Node1->Node2</title> <a xlink:title="Bandwidth: 1544kbps
Using link: 12%
VOIP calls: 4
Packet rate: 10000
Packet loss: 2"> <path fill="none" stroke="black" d="M65,-82.2678C65,-73.5404 65,-64.358 65,-55.8964"/> <polygon fill="black" stroke="black" points="68.5001,-55.6524 65,-45.6524 61.5001,-55.6525 68.5001,-55.6524"/> </a> </g> </g> </svg> I want to change some atributes: for example " VOIP calls: 4 " -changing "4" to value from Database(LDAP) without refreshing whole SVG graph <a xlink:title="Bandwidth: 1544kbps
Using link: 12%
VOIP calls: 4
Packet rate: 10000
Packet loss: 2"> Thank you for your answers

Read the article
Core-Plot graph in a UIViewController

- by Kenneth

Hi guys, im trying to put a Coreplot graph in a UIView. Some questions, should i do it in XIB? or should i do it programmically ? If so how should i write the codes? etc. I actually have two Classes. one called GraphView which is supposed to hold the Coreplot graph. Another called CorePlotViewController. Thx for looking guys.

Read the article
PHP given a series of arbitrary numbers, how can I choose a logical max value on a line graph?

- by stormist

I am constructing a line graph in PHP. I was setting the max value of the line graph to the max value of my collection of items, but this ended up making the graph less readable you are unable to view the highest line on the graph as it intersects with the top of it. So what I need is basically a formula to take a set of numbers and calculate what the logical max value of on the line graph should be.. so some examples 3500 250 10049 45394 434 312 Max value on line graph should probably be 50000 493 412 194 783 457 344 max value on line graph would ideally be 1000 545 649 6854 5485 11545 In this case, 12000 makes sense as max value So something as simple as rounding upward to the nearest thousandth might work but I'd need it to progressively increase as the numbers got bigger. (50000 instead of 46,000 in first example) The maximum these numbers will ever be is about a million. Any recommendations would be greatly appreciated, thank you.

Read the article
Howto Plot "Reverse" Cumulative Frequency Graph With ECDF

- by neversaint

I have no problem plotting the following cumulative frequency graph plot like this. library(Hmisc) pre.test <- rnorm(100,50,10) post.test <- rnorm(100,55,10) x <- c(pre.test, post.test) g <- c(rep('Pre',length(pre.test)),rep('Post',length(post.test))) Ecdf(x, group=g, what="f", xlab='Test Results', label.curves=list(keys=1:2)) But I want to show the graph in forms of the "reverse" cumulative frequency of values x ? (i.e. something equivalent to what="1-f"). Is there a way to do it? Other suggestions in R other than using Hmisc are also very much welcomed.

Read the article
Graph Tour with Uniform Cost Search in Java

- by user324817

Hi. I'm new to this site, so hopefully you guys don't mind helping a nub. Anyway, I've been asked to write code to find the shortest cost of a graph tour on a particular graph, whose details are read in from file. The graph is shown below: http://img339.imageshack.us/img339/8907/graphr.jpg This is for an Artificial Intelligence class, so I'm expected to use a decent enough search method (brute force has been allowed, but not for full marks). I've been reading, and I think that what I'm looking for is an A* search with constant heuristic value, which I believe is a uniform cost search. I'm having trouble wrapping my head around how to apply this in Java. Basically, here's what I have: Vertex class - ArrayList<Edge> adjacencies; String name; int costToThis; Edge class - final Vertex target; public final int weight; Now at the moment, I'm struggling to work out how to apply the uniform cost notion to my desired goal path. Basically I have to start on a particular node, visit all other nodes, and end on that same node, with the lowest cost. As I understand it, I could use a PriorityQueue to store all of my travelled paths, but I can't wrap my head around how I show the goal state as the starting node with all other nodes visited. Here's what I have so far, which is pretty far off the mark: public static void visitNode(Vertex vertex) { ArrayList<Edge> firstEdges = vertex.getAdjacencies(); for(Edge e : firstEdges) { e.target.costToThis = e.weight + vertex.costToThis; queue.add(e.target); } Vertex next = queue.remove(); visitNode(next); } Initially this takes the starting node, then recursively visits the first node in the PriorityQueue (the path with the next lowest cost). My problem is basically, how do I stop my program from following a path specified in the queue if that path is at the goal state? The queue currently stores Vertex objects, but in my mind this isn't going to work as I can't store whether other vertices have been visited inside a Vertex object. Help is much appreciated! Josh

Read the article
Algorithm -- Given an array of size n. It contains numbers in the range 1 to n. Each number is prese

- by sandeep

Given an array of size n. It contains numbers in the range 1 to n. Each number is present at least once but some numebrs may be missing. How to find the missing numbers.

Read the article
Line graph disappears after new line is added

- by tonystinge

I am having trouble uploading a large .csv file to my HIGHCHART graph. I've been able to graph an 85KB up to 1486 lines by 9 (I) columns. Here is an example: TimeStamp Temp_1_01 Temp_1_02 Temp_2_01 Temp_2_02 Temp_3_01 Temp_3_02 Temp_4_01 Temp_4_02 5/15/2014, 3:25 408 487 63 84 67 91 63 78 5/15/2014 3:30 408 487 63 84 67 91 63 78 5/15/2014 3:35 407 489 63 84 67 91 63 78 5/15/2014 3:40 408 488 63 84 67 91 63 78 5/15/2014 3:44 408 488 63 84 67 91 63 78 ... 5/22/2014 9:40 483 421 0 93 76 95 72 89 When I add a new line the line graph disappears. Any suggestions? Here is the javascript: $.get('Dropbox/geo/sites/GC_Room/loveland.csv', function(data) { // Split the lines var lines = data.split('\n'); var i = 0; var csvData = []; // Iterate over the lines and add categories or series $.each(lines, function(lineNo, line) { csvData[i] = line.split(','); i = i + 1; }); var columns = csvData[0]; var categories = [], series = []; for(var colIndex=0,len=columns.length; colIndex<len; colIndex++) { //first row data as series's name var seriesItem= { data:[], name:csvData[0][colIndex] }; for(var rowIndex=1,rowCnt=csvData.length; rowIndex<rowCnt; rowIndex++) { //first column data as categories, if (colIndex == 0) { categories.push(csvData[rowIndex][0]); } else if(parseFloat(csvData[rowIndex][colIndex])) // <-- here { seriesItem.data.push(parseFloat(csvData[rowIndex][colIndex])); } }; //except first column if(colIndex>0)series.push(seriesItem); } // Create the chart var chart = new Highcharts.Chart( { chart: { alignTick: false, renderTo: 'LANE_METALS', type: 'line' }, title: { text: 'Monthly Average Temperature', x: -20 //center }, subtitle: { text: 'Source: LANE METALS', x: -20 }, xAxis: { categories: categories, labels: { step: 200, text: 'Time', }, tickWidth: 0 }, yAxis: { title: { text: 'Temperature (\xB0C)' }, min: 0 }, tooltip: { formatter: function() { return '<b>'+ this.series.name +'</b><br/>'+ this.x +': '+ this.y +'\xB0C'; } }, legend: { layout: 'vertical', //backgroundColor: '#FFFFFF', //floating: true, align: 'left', //x: 100, verticalAlign: 'top', //y: 70, borderWidth: 0 }, plotOptions: { area: { turboThreshold: 0, stacking: 'normal', lineColor: '#666666', lineWidth: 1, marker: { lineWidth: 1, lineColor: '#666666' } } }, series: series }); });

Read the article
Howto plot two cumulative frequency graph together

- by neversaint

I have data that looks like this: #val Freq1 Freq2 0.000 178 202 0.001 4611 5300 0.002 99 112 0.003 26 30 0.004 17 20 0.005 15 20 0.006 11 14 0.007 11 13 0.008 13 13 ...many more lines.. Full data can be found here: http://dpaste.com/173536/plain/ What I intend to do is to have a cumulative graph with "val" as x-axis with "Freq1" & "Freq2" as y-axis, plot together in 1 graph. I have this code. But it creates two plots instead of 1. dat <- read.table("stat.txt",header=F); val<-dat$V1 freq1<-dat$V2 freq2<-dat$V3 valf1<-rep(val,freq1) valf2<-rep(val,freq2) valfreq1table<- table(valf1) valfreq2table<- table(valf2) cumfreq1=c(0,cumsum(valfreq1table)) cumfreq2=c(0,cumsum(valfreq2table)) plot(cumfreq1, ylab="CumFreq",xlab="Loglik Ratio") lines(cumfreq1) plot(cumfreq2, ylab="CumFreq",xlab="Loglik Ratio") lines(cumfreq2) What's the right way to approach this?

Read the article
Sorting a list of numbers with modified cost

- by David

First, this was one of the four problems we had to solve in a project last year and I couldn’t find a suitable algorithm so we handle in a brute force solution. Problem: The numbers are in a list that is not sorted and supports only one type of operation. The operation is defined as follows: Given a position i and a position j the operation moves the number at position i to position j without altering the relative order of the other numbers. If i j, the positions of the numbers between positions j and i - 1 increment by 1, otherwise if i < j the positions of the numbers between positions i+1 and j decreases by 1. This operation requires i steps to find a number to move and j steps to locate the position to which you want to move it. Then the number of steps required to move a number of position i to position j is i+j. We need to design an algorithm that given a list of numbers, determine the optimal (in terms of cost) sequence of moves to rearrange the sequence. Attempts: Part of our investigation was around NP-Completeness, we make it a decision problem and try to find a suitable transformation to any of the problems listed in Garey and Johnson’s book: Computers and Intractability with no results. There is also no direct reference (from our point of view) to this kind of variation in Donald E. Knuth’s book: The art of Computer Programing Vol. 3 Sorting and Searching. We also analyzed algorithms to sort linked lists but none of them gives a good idea to find de optimal sequence of movements. Note that the idea is not to find an algorithm that orders the sequence, but one to tell me the optimal sequence of movements in terms of cost that organizes the sequence, you can make a copy and sort it to analyze the final position of the elements if you want, in fact we may assume that the list contains the numbers from 1 to n, so we know where we want to put each number, we are just concerned with minimizing the total cost of the steps. We tested several greedy approaches but all of them failed, divide and conquer sorting algorithms can’t be used because they swap with no cost portions of the list and our dynamic programing approaches had to consider many cases. The brute force recursive algorithm takes all the possible combinations of movements from i to j and then again all the possible moments of the rest of the element’s, at the end it returns the sequence with less total cost that sorted the list, as you can imagine the cost of this algorithm is brutal and makes it impracticable for more than 8 elements. Our observations: n movements is not necessarily cheaper than n+1 movements (unlike swaps in arrays that are O(1)). There are basically two ways of moving one element from position i to j: one is to move it directly and the other is to move other elements around i in a way that it reaches the position j. At most you make n-1 movements (the untouched element reaches its position alone). If it is the optimal sequence of movements then you didn’t move the same element twice.

Read the article
State of the art Culling and Batching techniques in rendering

- by Kristian Skarseth

I'm currently working with upgrading and restructuring an OpenGL render engine. The engine is used for visualising large scenes of architectural data (buildings with interior), and the amount of objects can become rather large. As is the case with any building, there is a lot of occluded objects within walls, and you naturally only see the objects that are in the same room as you, or the exterior if you are on the outside. This leaves a large number of objects that should be occluded through occlusion culling and frustum culling. At the same time there is a lot of repetative geometry that can be batched in renderbatches, and also a lot of objects that can be rendered with instanced rendering. The way I see it, it can be difficult to combine renderbatching and culling in an optimal fashion. If you batch too many objects in the same VBO it's difficult to cull the objects on the CPU in order to skip rendering that batch. At the same time if you skip the culling on the cpu, a lot of objects will be processed by the GPU while they are not visible. If you skip batching copletely in order to more easily cull on the CPU, there will be an unwanted high amount of render calls. I have done some research into existing techniques and theories as to how these problems are solved in modern graphics, but I have not been able to find any concrete solution. An idea a colleague and me came up with was restricting batches to objects relatively close to eachother e.g all chairs in a room or within a radius of n meeters. This could be simplified and optimized through use of oct-trees. Does anyone have any pointers to techniques used for scene managment, culling, batching etc in state of the art modern graphics engines?

Read the article
Facebook Stories for Retailers

- by David Dorf

Getting people to "like" a brand is important because it opens the door to a possible B2C relationship. Once a person likes that brand, the brand can post to their newsfeed with promotions, announcements, and surveys. At least for me, I "hide" the noisy brands and just monitor the ones that keep posts under 4 times a week. I see lots of people, especially with fashion brands, comment on postings at which point the posting is seen by their network. A metric I've heard (but not verified) is that for every person that comments, ten of their friends see the original posting. That's a pretty cheap way to communicate to potential customers in a viral way. Over at mainstreet.com they compiled the a list of the top liked retailers on Facebook as of Feb 1, 2011. They are listed below: 19,414,892 Starbucks 11,302,939 Victoria's Secret 7,925,184 Zara 7,032,398 McDonald's 6,117,222 H&M 5,400,586 Taco Bell 4,665,760 Subway 4,494,849 Lacoste 4,185,570 Hollister 3,973,181 Forever 21 So I guess the public likes their fast-food and fashion. To take this to the next level, Facebook is now displaying Sponsored Stories, which I saw for the first time on my page this weekend. I found this picture at the Wall Blog that depicits Sponsored Stories very well. Over on the right-hand column of a person's page, where they see advertisements and such, Facebook will post stories involving their network of friends and their interaction with sponsored brands. Now their "likes" can suddenly become your ads. "Jessica and Philip like Starbucks. What are you waiting for?" This is another great way to take messages viral by accessing social graphs. As usual there will be a certain level of outcry from privacy advocates, but given the other more iniquitous issues, I believe this will fall by the wayside. Retailers should consider using Sponsored Stories to increase their Likes, and thus increase their voice in the social world.

Read the article
Engine Rendering pipeline : Making shaders generic

- by fakhir

I am trying to make a 2D game engine using OpenGL ES 2.0 (iOS for now). I've written Application layer in Objective C and a separate self contained RendererGLES20 in C++. No GL specific call is made outside the renderer. It is working perfectly. But I have some design issues when using shaders. Each shader has its own unique attributes and uniforms that need to be set just before the main draw call (glDrawArrays in this case). For instance, in order to draw some geometry I would do: void RendererGLES20::render(Model * model) { // Set a bunch of uniforms glUniformMatrix4fv(.......); // Enable specific attributes, can be many glEnableVertexAttribArray(......); // Set a bunch of vertex attribute pointers: glVertexAttribPointer(positionSlot, 2, GL_FLOAT, GL_FALSE, stride, m->pCoords); // Now actually Draw the geometry glDrawArrays(GL_TRIANGLES, 0, m->vertexCount); // After drawing, disable any vertex attributes: glDisableVertexAttribArray(.......); } As you can see this code is extremely rigid. If I were to use another shader, say ripple effect, i would be needing to pass extra uniforms, vertex attribs etc. In other words I would have to change the RendererGLES20 render source code just to incorporate the new shader. Is there any way to make the shader object totally generic? Like What if I just want to change the shader object and not worry about game source re-compiling? Any way to make the renderer agnostic of uniforms and attributes etc?. Even though we need to pass data to uniforms, what is the best place to do that? Model class? Is the model class aware of shader specific uniforms and attributes? Following shows Actor class: class Actor : public ISceneNode { ModelController * model; AIController * AI; }; Model controller class: class ModelController { class IShader * shader; int textureId; vec4 tint; float alpha; struct Vertex * vertexArray; }; Shader class just contains the shader object, compiling and linking sub-routines etc. In Game Logic class I am actually rendering the object: void GameLogic::update(float dt) { IRenderer * renderer = g_application->GetRenderer(); Actor * a = GetActor(id); renderer->render(a->model); } Please note that even though Actor extends ISceneNode, I haven't started implementing SceneGraph yet. I will do that as soon as I resolve this issue. Any ideas how to improve this? Related design patterns etc? Thank you for reading the question.

Read the article
OpenGraph tags and HTML5 validity

- by netmano

I have a HTML5 based page, and I inculded the OpenGraph tags according to it's documentation. Also I checked with Facebook Debug, and it can parse the metadata. But when I use W3C Validator, it reports the OG tags as error: Attribute content not allowed on element meta at this point. <meta property="fb:admins" content="...." /> Attribute content not allowed on element meta at this point. <meta property="og:url" content="http://www...."> They are all in the <head>. I would need my page be "valid" HTML5 and OG tags, as well. Could you help me giving a hint how can it be achieved? UPDATE: The name version also invalid: <meta name='fb:admins' content=''>

Read the article
How to avoid game objects accidentally deleting themselves in C++

- by Tom Dalling

Let's say my game has a monster that can kamikaze explode on the player. Let's pick a name for this monster at random: a Creeper. So, the Creeper class has a method that looks something like this: void Creeper::kamikaze() { EventSystem::postEvent(ENTITY_DEATH, this); Explosion* e = new Explosion; e->setLocation(this->location()); this->world->addEntity(e); } The events are not queued, they get dispatched immediately. This causes the Creeper object to get deleted somewhere inside the call to postEvent. Something like this: void World::handleEvent(int type, void* context) { if(type == ENTITY_DEATH){ Entity* ent = dynamic_cast<Entity*>(context); removeEntity(ent); delete ent; } } Because the Creeper object gets deleted while the kamikaze method is still running, it will crash when it tries to access this->location(). One solution is to queue the events into a buffer and dispatch them later. Is that the common solution in C++ games? It feels like a bit of a hack, but that might just be because of my experience with other languages with different memory management practices. In C++, is there a better general solution to this problem where an object accidentally deletes itself from inside one of its methods?

Read the article
Nested Entities and calculation on leaf entity property - SQL or NoSQL approach

- by Chandu

I am working on a hobby project called Menu/Recipe Management. This is how my entities and their relations look like. A Nutrient has properties Code and Value An Ingredient has a collection of Nutrients A Recipe has a Collection of Ingredients and occasionally can have a collection of other recipes A Meal has a Collection of Recipes and Ingredients A Menu has a Collection of Meals The relations can be depicted as In one of the pages, for a selected menu I need to display the effective nutrients information calculated based on its constituents (Meals, Recipes, Ingredients and the corresponding nutrients). As of now am using SQL Server to store the data and I am navigating the chain from my C# code, starting from each meal of the menu and then aggregating the nutrient values. I think this is not an efficient way as this calculation is being done every time the page is requested and the constituents change occasionally. I was thinking about a having a background service that maintains a table called MenuNutrients ({MenuId, NutrientId, Value}) and will populate/update this table with the effective nutrients when any of the component (Meal, Recipe, Ingredient) changes. I feel that a GraphDB would be a good fit for this requirement, but my exposure to NoSQL is limited. I want to know what are the alternative solutions/approaches to this requirement of displaying the nutrients of a given menu. Hope my description of the scenario is clear.

Read the article
Legal responsibility of public posts

- by Murdock

Given a public site with no logins: I let people post links to public Facebook profiles, and my site fetches the profile picture and displays it. Would it be ok if I just told people to post profiles of which they had the owner’s permission? Does such a statement exonerate me from copyright infringements and place the burden on the user? Edit: For bonus points. Can the statement just be a notice under the button (that will save the link) that says that "By clicking this button you agree to the terms and conditions" with maybe a link to the terms and conditions.

Read the article
How to design the scenarios in a platform game?

- by ReyLitch

I am developing a 3D platform game like Metroid Fusion with XNA. I have many classes for different elements as models, game screens, postprocessing and so on. Now I want to start designing the scenarios but I think that the scenarios needed in a platform game are not as conventional (by conventional I say something like this). I am very lost and not know where to start and how to structure it. Thanks in advance.

Read the article
Facebook Like button warning, but prevents sharing

- by Steve

I added a FB Like button to my Wordpress template, and when I click Like, I receive an error, which pops up and says: There was an error liking the page. If you are the page owner, please try running your page through the linter on the Facebook devsite (https://developers.facebook.com/tools/lint/) and fixing any errors. The Lint Checker (now) gives no Error or Warnings, after I removed a duplicate og:description tag. Why is it not working?

Read the article

< Previous Page | 51 52 53 54 55 56 57 58 59 60 61 62 | Next Page >