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  • Coordinates from 3DS Max to XNA 3.5

    - by David Conde
    Hello My problem is this. I have a simple box made in 3DS Max 2009, the Box is 10x10x10. I've tried to load it on XNA and traslate the camera for 15 units, but I can seem to find the values needed to see the box properly. Can anyone point me to a good resource where I can find some good introduction to XNA coordinate system and how is a simple box made in 3DS Max imported properly Best regards, David

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  • Investigation: Can different combinations of components effect Dataflow performance?

    - by jamiet
    Introduction The Dataflow task is one of the core components (if not the core component) of SQL Server Integration Services (SSIS) and often the most misunderstood. This is not surprising, its an incredibly complicated beast and we’re abstracted away from that complexity via some boxes that go yellow red or green and that have some lines drawn between them. Example dataflow In this blog post I intend to look under that facade and get into some of the nuts and bolts of the Dataflow Task by investigating how the decisions we make when building our packages can affect performance. I will do this by comparing the performance of three dataflows that all have the same input, all produce the same output, but which all operate slightly differently by way of having different transformation components. I also want to use this blog post to challenge a common held opinion that I see perpetuated over and over again on the SSIS forum. That is, that people assume adding components to a dataflow will be detrimental to overall performance. Its not surprising that people think this –it is intuitive to think that more components means more work- however this is not a view that I share. I have always been of the opinion that there are many factors affecting dataflow duration and the number of components is actually one of the less important ones; having said that I have never proven that assertion and that is one reason for this investigation. I have actually seen evidence that some people think dataflow duration is simply a function of number of rows and number of components. I’ll happily call that one out as a myth even without any investigation!  The Setup I have a 2GB datafile which is a list of 4731904 (~4.7million) customer records with various attributes against them and it contains 2 columns that I am going to use for categorisation: [YearlyIncome] [BirthDate] The data file is a SSIS raw format file which I chose to use because it is the quickest way of getting data into a dataflow and given that I am testing the transformations, not the source or destination adapters, I want to minimise external influences as much as possible. In the test I will split the customers according to month of birth (12 of those) and whether or not their yearly income is above or below 50000 (2 of those); in other words I will be splitting them into 24 discrete categories and in order to do it I shall be using different combinations of SSIS’ Conditional Split and Derived Column transformation components. The 24 datapaths that occur will each input to a rowcount component, again because this is the least resource intensive means of terminating a datapath. The test is being carried out on a Dell XPS Studio laptop with a quad core (8 logical Procs) Intel Core i7 at 1.73GHz and Samsung SSD hard drive. Its running SQL Server 2008 R2 on Windows 7. The Variables Here are the three combinations of components that I am going to test:     One Conditional Split - A single Conditional Split component CSPL Split by Month of Birth and income category that will use expressions on [YearlyIncome] & [BirthDate] to send each row to one of 24 outputs. This next screenshot displays the expression logic in use: Derived Column & Conditional Split - A Derived Column component DER Income Category that adds a new column [IncomeCategory] which will contain one of two possible text values {“LessThan50000”,”GreaterThan50000”} and uses [YearlyIncome] to determine which value each row should get. A Conditional Split component CSPL Split by Month of Birth and Income Category then uses that new column in conjunction with [BirthDate] to determine which of the same 24 outputs to send each row to. Put more simply, I am separating the Conditional Split of #1 into a Derived Column and a Conditional Split. The next screenshots display the expression logic in use: DER Income Category         CSPL Split by Month of Birth and Income Category       Three Conditional Splits - A Conditional Split component that produces two outputs based on [YearlyIncome], one for each Income Category. Each of those outputs will go to a further Conditional Split that splits the input into 12 outputs, one for each month of birth (identical logic in each). In this case then I am separating the single Conditional Split of #1 into three Conditional Split components. The next screenshots display the expression logic in use: CSPL Split by Income Category         CSPL Split by Month of Birth 1& 2       Each of these combinations will provide an input to one of the 24 rowcount components, just the same as before. For illustration here is a screenshot of the dataflow containing three Conditional Split components: As you can these dataflows have a fair bit of work to do and remember that they’re doing that work for 4.7million rows. I will execute each dataflow 10 times and use the average for comparison. I foresee three possible outcomes: The dataflow containing just one Conditional Split (i.e. #1) will be quicker There is no significant difference between any of them One of the two dataflows containing multiple transformation components will be quicker Regardless of which of those outcomes come to pass we will have learnt something and that makes this an interesting test to carry out. Note that I will be executing the dataflows using dtexec.exe rather than hitting F5 within BIDS. The Results and Analysis The table below shows all of the executions, 10 for each dataflow. It also shows the average for each along with a standard deviation. All durations are in seconds. I’m pasting a screenshot because I frankly can’t be bothered with the faffing about needed to make a presentable HTML table. It is plain to see from the average that the dataflow containing three conditional splits is significantly faster, the other two taking 43% and 52% longer respectively. This seems strange though, right? Why does the dataflow containing the most components outperform the other two by such a big margin? The answer is actually quite logical when you put some thought into it and I’ll explain that below. Before progressing, a side note. The standard deviation for the “Three Conditional Splits” dataflow is orders of magnitude smaller – indicating that performance for this dataflow can be predicted with much greater confidence too. The Explanation I refer you to the screenshot above that shows how CSPL Split by Month of Birth and salary category in the first dataflow is setup. Observe that there is a case for each combination of Month Of Date and Income Category – 24 in total. These expressions get evaluated in the order that they appear and hence if we assume that Month of Date and Income Category are uniformly distributed in the dataset we can deduce that the expected number of expression evaluations for each row is 12.5 i.e. 1 (the minimum) + 24 (the maximum) divided by 2 = 12.5. Now take a look at the screenshots for the second dataflow. We are doing one expression evaluation in DER Income Category and we have the same 24 cases in CSPL Split by Month of Birth and Income Category as we had before, only the expression differs slightly. In this case then we have 1 + 12.5 = 13.5 expected evaluations for each row – that would account for the slightly longer average execution time for this dataflow. Now onto the third dataflow, the quick one. CSPL Split by Income Category does a maximum of 2 expression evaluations thus the expected number of evaluations per row is 1.5. CSPL Split by Month of Birth 1 & CSPL Split by Month of Birth 2 both have less work to do than the previous Conditional Split components because they only have 12 cases to test for thus the expected number of expression evaluations is 6.5 There are two of them so total expected number of expression evaluations for this dataflow is 6.5 + 6.5 + 1.5 = 14.5. 14.5 is still more than 12.5 & 13.5 though so why is the third dataflow so much quicker? Simple, the conditional expressions in the first two dataflows have two boolean predicates to evaluate – one for Income Category and one for Month of Birth; the expressions in the Conditional Split in the third dataflow however only have one predicate thus they are doing a lot less work. To sum up, the difference in execution times can be attributed to the difference between: MONTH(BirthDate) == 1 && YearlyIncome <= 50000 and MONTH(BirthDate) == 1 In the first two dataflows YearlyIncome <= 50000 gets evaluated an average of 12.5 times for every row whereas in the third dataflow it is evaluated once and once only. Multiply those 11.5 extra operations by 4.7million rows and you get a significant amount of extra CPU cycles – that’s where our duration difference comes from. The Wrap-up The obvious point here is that adding new components to a dataflow isn’t necessarily going to make it go any slower, moreover you may be able to achieve significant improvements by splitting logic over multiple components rather than one. Performance tuning is all about reducing the amount of work that needs to be done and that doesn’t necessarily mean use less components, indeed sometimes you may be able to reduce workload in ways that aren’t immediately obvious as I think I have proven here. Of course there are many variables in play here and your mileage will most definitely vary. I encourage you to download the package and see if you get similar results – let me know in the comments. The package contains all three dataflows plus a fourth dataflow that will create the 2GB raw file for you (you will also need the [AdventureWorksDW2008] sample database from which to source the data); simply disable all dataflows except the one you want to test before executing the package and remember, execute using dtexec, not within BIDS. If you want to explore dataflow performance tuning in more detail then here are some links you might want to check out: Inequality joins, Asynchronous transformations and Lookups Destination Adapter Comparison Don’t turn the dataflow into a cursor SSIS Dataflow – Designing for performance (webinar) Any comments? Let me know! @Jamiet

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  • Collision filtering by object, team

    - by Bill Zimmerman
    Hi, I am looking for a good method to determine which objects will be considered for collision with other objects. My current idea is that each object has the following properties: alwaysCollidesWith = [list of objects that will always trigger a collision check] neverCollidesWith = [lost of objects that will never be considered] teamCollidesWith = [list of objects that will be checked, provided they belong to a different team] For example: -projectiles never have to be checked for collisions with other projectiles -players are always checked for collisions with players, regardless of team -projectiles are only considered for collisions if they collide with another teams players Does anyone see any weaknesses with this approach? Can anyone recommend a better approach?

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  • Reflections based on distance from plane

    - by Andrea Benedetti
    Let's consider, for example, a surface like the volleyball court, we can see that legs and shoes of the players are reflected, with a blur effect, but body and stadium don't (as each object not near to the court). I've already made a reflection effect, but it works as a specular reflection, and I need to achieve an effect like the photo above. So, I would like to make a reflection that is based on the distance between the object and the plane, in this manner a close object would reflect more than an object that is positioned far away from the plane. What is the best way to achieve this effect? My first idea was to use the depth value (taken from the reflected camera), and use that value to blend between reflection and court. But I don't know if it's a correct way. Edit: as rendering engine I use Ogre that already provides a reflections system: reflecting the camera through a plane (obviously I can select the models to draw from the reflected camera). After a render to texture pass I can blend the reflected texture with the original plane. So, if possible, I'm looking for a way that best suits my system.

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  • What are reasons for Unity3D's owners to force rich guys buying Pro version?

    - by mhambra
    Well, I have to say that Unity is a really nice thing that can save one a dozen of hours on coding (letting instantly work on gameplay). But what's the idea of forcing (EULA) any party, which made over 100k last fiscal year, to purchase Pro instead of using normal edition!? It feels that this kind of licensing provides hidden benefits to rich guys over me, poor sloven, who can afford buying $3.5k license but obviously will not receive any additional cookies from it. And, by the way, anyone estimated how much Unity's source + Playstation + Xbox license will cost?

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  • How to make Rect of irregular shape sprite?

    - by Anil gupta
    I used masking for breaking an image as the below mention pattern now its breaking in different pieces but now i have one issue to make the Rect of each pieces, i need to drag the broken pieces and to adjust at correct position so that i can make again actual images. To drag and put at right positing i need to make Rect but i am not getting idea how to make Rect of this irregular shape, I will be very thankful to you, any idea or code to make rect . My previous Question is: How do I break an image into 6 or 8 pieces of different shapes? Thanks.

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  • Triangle - Rectangle Intersection in 2D

    - by Kevin Boyd
    I had previously asked this for 3D but now I changed my strategy and would like to do the intersection in 2D. The Rectangle is axis aligned and will always be in a fixed position, and has a constant shape and size, basically I want to clip the red areas of the triangles that extend outside the bounds of the rectangle The triangles could be in any position, shape or size, I my code I have a loop where I check the triangles one by one however I am still clueless about the math. I have identified 5 cases of triangle rectangle intersection as shown here. How do I find the intersection points of the triangle and the rectangle?

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  • How to implement Undo and Redo feature in as3

    - by Swati Singh
    I am going to create an application in that i have to implement an Undo and Redo feature. In the application there will be multiple objects located on stage and user can customize the position of the objects. But when user clicks on Undo the object go back to their default position and after clicking on redo object will move on the new position. So my question is how can i apply these feature in my application? Is there any library or any third party classes? Can some one help me? Thanks in advance.

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  • 45° Slopes in a Tile based 2D platformer

    - by xNidhogg
    I want to have simple 45° slopes in my tile based platformer, however I just cant seem to get the algorithm down. Please take a look at the code and video, maybe I'm missing the obvious? //collisionRectangle is the collision rectangle of the player with //origin at the top left and width and height //wantedPosition is the new position the player will be set to. //this is determined elsewhere by checking the bottom center point of the players rect if(_leftSlope || _rightSlope) { //Test bottom center point var calculationPoint = new Vector2(collisionRectangle.Center.X, collisionRectangle.Bottom); //Get the collision rectangle of the tile, origin is top-left Rectangle cellRect = _tileMap.CellWorldRectangle( _tileMap.GetCellByPixel(calculationPoint)); //Calculate the new Y coordinate depending on if its a left or right slope //CellSize = 8 float newY = _leftSlope ? (calculationPoint.X % CellSize) + cellRect.Y : (-1 * (calculationPoint.X % CellSize) - CellSize) + cellRect.Y; //reset variables so we dont jump in here next frame _leftSlope = false; _rightSlope = false; //now change the players Y according to the difference of our calculation wantedPosition.Y += newY - calculationPoint.Y; } Video of what it looks like: http://youtu.be/EKOWgD2muoc

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  • Billboard shader without distortion

    - by Nick Wiggill
    I use the standard approach to billboarding within Unity that is OK, but not ideal: transform.LookAt(camera). The problem is that this introduces distortion toward the edges of the viewport, especially as the field of view angle grows larger. This is unlike the perfect billboarding you'd see in eg. Doom when seeing an enemy from any angle and irrespective of where they are located in screen space. Obviously, there are ways to blit an image directly to the viewport, centred around a single vertex, but I'm not hot on shaders. Does anyone have any samples of this approach (GLSL if possible), or any suggestions as to why it isn't typically done this way (vs. the aforementioned quad transformation method)? EDIT: I was confused, thanks Nathan for the heads up. Of course, Causing the quads to look at the camera does not cause them to be parallel to the view plane -- which is what I need.

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  • Using XNA's XML content pipeline to read arrays of objects with different subtypes

    - by Mcguirk
    Using XNA's XML content importer, is it possible to read in an array of objects with different subtypes? For instance, assume these are my class definitions: public abstract class MyBaseClass { public string MyBaseData; } public class MySubClass0 : MyBaseClass { public int MySubData0; } public class MySubClass1 : MyBaseClass { public bool MySubData1; } And this is my XML file: <XnaContent> <Asset Type="MyBaseClass[]"> <Item> <!-- I want this to be an instance of MySubClass0 --> <MyBaseData>alpha</MyBaseData> <MySubData0>314</MySubData0> </Item> <Item> <!-- I want this to be an instance of MySubClass1 --> <MyBaseData>bravo</MyBaseData> <MySubData1>true</MySubData1> </Item> </Asset> </XnaContent> How do I specify that I want the first Item to be an instance of MySubclass0 and the second Item to be an instance of MySubclass1?

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  • Best way of storing voxels

    - by opiop65
    This should be a pretty easy question to answer, and I'm not looking for how to store the voxels data wise, I'm looking for the theory. Currently, my voxel engine has no global list of tiles. Each chunk has it's own list, and its hard to do things like collision detection or anything that may use tiles that are outside of its own chunk. I recently worked on procedural terrain with a non voxel engine. Now, I want to start using heightmaps in my voxel engine. But, I have a problem. If each chunk has its own list, then it will be pretty difficult to implement the heightmaps. My real question is, is should I store a global list of voxels independent of the chunks? And then I can just easily perform collision detection and terrain generation. However, it would probably be harder to do things such as frustum culling. So how should I store them?

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  • formula for replicating glTexGen in opengl es 2.0 glsl

    - by visualjc
    I also posted this on the main StackExchange, but this seems like a better place, but for give me for the double post if it shows up twice. I have been trying for several hours to implement a GLSL replacement for glTexGen with GL_OBJECT_LINEAR. For OpenGL ES 2.0. In Ogl GLSL there is the gl_TextureMatrix that makes this easier, but thats not available on OpenGL ES 2.0 / OpenGL ES Shader Language 1.0 Several sites have mentioned that this should be "easy" to do in a GLSL vert shader. But I just can not get it to work. My hunch is that I'm not setting the planes up correctly, or I'm missing something in my understanding. I've pored over the web. But most sites are talking about projected textures, I'm just looking to create UV's based on planar projection. The models are being built in Maya, have 50k polygons and the modeler is using planer mapping, but Maya will not export the UV's. So I'm trying to figure this out. I've looked at the glTexGen manpage information: g = p1xo + p2yo + p3zo + p4wo What is g? Is g the value of s in the texture2d call? I've looked at the site: http://www.opengl.org/wiki/Mathematics_of_glTexGen Another size explains the same function: coord = P1*X + P2*Y + P3*Z + P4*W I don't get how coord (an UV vec2 in my mind) is equal to the dot product (a scalar value)? Same problem I had before with "g". What do I set the plane to be? In my opengl c++ 3.0 code, I set it to [0, 0, 1, 0] (basically unit z) and glTexGen works great. I'm still missing something. My vert shader looks basically like this: WVPMatrix = World View Project Matrix. POSITION is the model vertex position. varying vec4 kOutBaseTCoord; void main() { gl_Position = WVPMatrix * vec4(POSITION, 1.0); vec4 sPlane = vec4(1.0, 0.0, 0.0, 0.0); vec4 tPlane = vec4(0.0, 1.0, 0.0, 0.0); vec4 rPlane = vec4(0.0, 0.0, 0.0, 0.0); vec4 qPlane = vec4(0.0, 0.0, 0.0, 0.0); kOutBaseTCoord.s = dot(vec4(POSITION, 1.0), sPlane); kOutBaseTCoord.t = dot(vec4(POSITION, 1.0), tPlane); //kOutBaseTCoord.r = dot(vec4(POSITION, 1.0), rPlane); //kOutBaseTCoord.q = dot(vec4(POSITION, 1.0), qPlane); } The frag shader precision mediump float; uniform sampler2D BaseSampler; varying mediump vec4 kOutBaseTCoord; void main() { //gl_FragColor = vec4(kOutBaseTCoord.st, 0.0, 1.0); gl_FragColor = texture2D(BaseSampler, kOutBaseTCoord.st); } I've tried texture2DProj in frag shader Here are some of the other links I've looked up http://www.gamedev.net/topic/407961-texgen-not-working-with-glsl-with-fixed-pipeline-is-ok/ Thank you in advance.

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  • What is the Xbox360's D3DRS_VIEWPORTENABLE equivalent on WinXP D3D9?

    - by Jim Buck
    I posted this on StackOverlow, but of course it should be posted here. I am maintaining a multiplatform codebase for Xbox360 and WinXP. I am seeing an issue on the XP side that appears to be related to D3DRS_VIEWPORTENABLE on the Xbox360 version not having an equivalent on WinXP D3D9. This article had an interesting idea, but the only way to construct an identity matrix is to supply negative numbers to D3DVIEWPORT9::X and D3DVIEWPORT9::Height, but they are unsigned numbers. (I tried to put in negative numbers anyway, but nothing interesting happened.) So, how does one emulate the behavior of D3DRS_VIEWPORTENABLE under WinXP/D3D9? (For clarity, the result I'm seeing is that a 2d screen-aligned quad works fine on Xbox360 but is offset/stretched on WinXP. In fact, the (0, 0) starts in the center of the screen on WinXP instead of in the lower-left corner like on the Xbox360 as a result of applying the viewport transform.) Update: I didn't have an Xbox360 devkit at the time I wrote up this question, but I've since gotten one. I commented out the disabling of the D3DRS_VIEWPORTENABLE state, and the exact same behavior resulted on the Xbox360 as on the WinXP build. So, there must be some DirectX magic to bridge the gap here for emulating D3DRS_VIEWPORTENABLE being turned off on WinXP.

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  • XNA `tex2Dlod` always returns transparent black

    - by feralin
    I want to sample a texture in a vertex shader, so at first I just tried using float2 texcoords = ...; color = tex2D(texture, texcoords); But apparently I cannot use tex2D in a vertex shader, and must use tex2Dlod. So then I changed the above code to color = tex2Dlod(texture, float4(texcoords, 0, 0)); But now color is always float4(0, 0, 0, 0) (i.e. transparent black). Why is this, and how can I fix it? EDIT: I know for a fact that the texture does not contain just transparent black pixels.

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  • How to apply numerical integration on a graph layout

    - by Cumatru
    I've done some basic 1 D integration, but i can't wrap my head around things and apply it to my graph layout. So, consider the picture below: if i drag the red node to the right, i'm forcing his position to my mouse position the other nodes will "follow" him, but how ? For Verlet, to compute the newPosition, i need the acceleration for every node and the currentPosition. That is what i don't understand. How to i compute the acceleration and the currentPosition ? The currentPosition will be the position of the RedNode ? If yes, doesn't that means that they will all overlap ? http://i.stack.imgur.com/NCKmO.jpg

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  • Playing NSF music in FMOD.net

    - by Tesserex
    So, as the title says, I want to be able to play NSF files using FMOD, because my project already uses FMOD and I'd rather not replace it. This will involve figuring out how existing players and emulators work and porting it. I haven't yet found an existing player that uses FMOD. My starting point is the MyNes source from http://sourceforge.net/projects/mynes/. There are two big steps between here and what I'm looking for. MyNes plays from a ROM, not NSF. So, I have to rip out the APU and get it to play NSF files. The MyNes APU uses SlimDX, so I have to convert that to FMOD.NET. I am really stuck about how to go about either of these, because I'm not that familiar with audio formats and it's hard finding resources online. So here are a few questions: From what I can tell from the NSF spec at http://kevtris.org/nes/nsfspec.txt, it's just contains the relevant memory section of the ROM, plus the header. If anyone can verify or correct this that would be great. The emulator APU uses data from the rest of the emulator to play, including things like cycle counts. I'm not sure what replaces this in a standalone player. Can't I just load all the music data at once into a stream and play it? Joining #1 and #2, does the header data from the NSF substitute for some of the ROM data in the emulator code? Using FMOD, will I be following the usercreatedsound example for loading a stream? And does this format count as PCM? Specifically MyNes says PCM8. Any tips on loading / playing the stream in FMOD are appreciated. As an aside, I don't really understand the loading / playing sections of the spec I linked at all. It seems to apply to 6502 systems / emulators only and not to my situation. I know it's a long shot for anyone here to have enough experience in this area to help, but anything you can provide is definitely appreciated. A link to an existing .NET library that does this would be even better, but I don't believe one exists.

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  • Giving a Bomberman AI intelligent bomb placement

    - by Paul Manta
    I'm trying to implement an AI algorithm for Bomberman. Currently I have a working but not very smart rudimentary implementation (the current AI is overzealous in placing bombs). This is the first AI I've ever tried implementing and I'm a bit stuck. The more sophisticated algorithms I have in mind (the ones that I expect to make better decisions) are too convoluted to be good solutions. What general tips do you have for implementing a Bomberman AI? Are there radically different approaches for making the bot either more defensive or offensive? Edit: Current algorithm My current algorithm goes something like this (pseudo-code): 1) Try to place a bomb and then find a cell that is safe from all the bombs, including the one that you just placed. To find that cell, iterate over the four directions; if you can find any safe divergent cell and reach it in time (eg. if the direction is up or down, look for a cell that is found to the left or right of this path), then it's safe to place a bomb and move in that direction. 2) If you can't find and safe divergent cells, try NOT placing a bomb and look again. This time you'll only need to look for a safe cell in only one direction (you don't have to diverge from it). 3) If you still can't find a safe cell, don't do anything. for $(direction) in (up, down, left, right): place bomb at current location if (can find and reach divergent safe cell in current $(direction)): bomb = true move = $(direction) return for $(direction) in (up, down, left, right): do not place bomb at current location if (any safe cell in the current $(direction)): bomb = false move = $(direction) return else: bomb = false move = stay_put This algorithm makes the bot very trigger-happy (it'll place bombs very frequently). It doesn't kill itself, but it does have a habit of making itself vulnerable by going into dead ends where it can be blocked and killed by the other players. Do you have any suggestions on how I might improve this algorithm? Or maybe I should try something completely different? One of the problems with this algorithm is that it tends to leave the bot with very few (frequently just one) safe cells on which it can stand. This is because the bot leaves a trail of bombs behind it, as long as it doesn't kill itself. However, leaving a trail of bombs behind leaves few places where you can hide. If one of the other players or bots decide to place a bomb somewhere near you, it often happens that you have no place to hide and you die. I need a better way to decide when to place bombs.

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  • Popular genres in Asian (non-Japanese) markets?

    - by mummey
    Hello, From time-to-time I've wondered what kind of games are popular in Asia (India, China, Korea, Singapore, etc...). I hear about developers in the US and UK who outsource work there, but what goes into the games they make for themselves? Related, you hear these days about how Japanese developers have been marketing their games more for American audiences these days (with mixed success). In what ways could American developers aim their development toward Asian audiences?

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  • How can I write only to the stencil buffer in OpenGL ES 2.0?

    - by stephelton
    I'd like to write to the stencil buffer without incurring the cost of my expensive shaders. As I understand it, I write to the stencil buffer as a 'side effect' of rendering something. In this first pass where I write to the stencil buffer, I don't want to write anything to the color or depth buffer, and I definitely don't want to run through my lighting equations in my shaders. Do I need to create no-op shaders for this (and can I just discard fragments), or is there a better way to do this? As the title says, I'm using OpenGL ES 2.0. I haven't used the stencil buffer before, so if I seem to be misunderstanding something, feel free to be verbose.

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  • Optimizing collision engine bottleneck

    - by Vittorio Romeo
    Foreword: I'm aware that optimizing this bottleneck is not a necessity - the engine is already very fast. I, however, for fun and educational purposes, would love to find a way to make the engine even faster. I'm creating a general-purpose C++ 2D collision detection/response engine, with an emphasis on flexibility and speed. Here's a very basic diagram of its architecture: Basically, the main class is World, which owns (manages memory) of a ResolverBase*, a SpatialBase* and a vector<Body*>. SpatialBase is a pure virtual class which deals with broad-phase collision detection. ResolverBase is a pure virtual class which deals with collision resolution. The bodies communicate to the World::SpatialBase* with SpatialInfo objects, owned by the bodies themselves. There currenly is one spatial class: Grid : SpatialBase, which is a basic fixed 2D grid. It has it's own info class, GridInfo : SpatialInfo. Here's how its architecture looks: The Grid class owns a 2D array of Cell*. The Cell class contains two collection of (not owned) Body*: a vector<Body*> which contains all the bodies that are in the cell, and a map<int, vector<Body*>> which contains all the bodies that are in the cell, divided in groups. Bodies, in fact, have a groupId int that is used for collision groups. GridInfo objects also contain non-owning pointers to the cells the body is in. As I previously said, the engine is based on groups. Body::getGroups() returns a vector<int> of all the groups the body is part of. Body::getGroupsToCheck() returns a vector<int> of all the groups the body has to check collision against. Bodies can occupy more than a single cell. GridInfo always stores non-owning pointers to the occupied cells. After the bodies move, collision detection happens. We assume that all bodies are axis-aligned bounding boxes. How broad-phase collision detection works: Part 1: spatial info update For each Body body: Top-leftmost occupied cell and bottom-rightmost occupied cells are calculated. If they differ from the previous cells, body.gridInfo.cells is cleared, and filled with all the cells the body occupies (2D for loop from the top-leftmost cell to the bottom-rightmost cell). body is now guaranteed to know what cells it occupies. For a performance boost, it stores a pointer to every map<int, vector<Body*>> of every cell it occupies where the int is a group of body->getGroupsToCheck(). These pointers get stored in gridInfo->queries, which is simply a vector<map<int, vector<Body*>>*>. body is now guaranteed to have a pointer to every vector<Body*> of bodies of groups it needs to check collision against. These pointers are stored in gridInfo->queries. Part 2: actual collision checks For each Body body: body clears and fills a vector<Body*> bodiesToCheck, which contains all the bodies it needs to check against. Duplicates are avoided (bodies can belong to more than one group) by checking if bodiesToCheck already contains the body we're trying to add. const vector<Body*>& GridInfo::getBodiesToCheck() { bodiesToCheck.clear(); for(const auto& q : queries) for(const auto& b : *q) if(!contains(bodiesToCheck, b)) bodiesToCheck.push_back(b); return bodiesToCheck; } The GridInfo::getBodiesToCheck() method IS THE BOTTLENECK. The bodiesToCheck vector must be filled for every body update because bodies could have moved meanwhile. It also needs to prevent duplicate collision checks. The contains function simply checks if the vector already contains a body with std::find. Collision is checked and resolved for every body in bodiesToCheck. That's it. So, I've been trying to optimize this broad-phase collision detection for quite a while now. Every time I try something else than the current architecture/setup, something doesn't go as planned or I make assumption about the simulation that later are proven to be false. My question is: how can I optimize the broad-phase of my collision engine maintaining the grouped bodies approach? Is there some kind of magic C++ optimization that can be applied here? Can the architecture be redesigned in order to allow for more performance? Actual implementation: SSVSCollsion Body.h, Body.cpp World.h, World.cpp Grid.h, Grid.cpp Cell.h, Cell.cpp GridInfo.h, GridInfo.cpp

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  • Help implementing virtual d-pad

    - by Moshe
    Short Version: I am trying to move a player around on a tilemap, keeping it centered on its tile, while smoothly controlling it with SneakyInput virtual Joystick. My movement is jumpy and hard to control. What's a good way to implement this? Long Version: I'm trying to get a tilemap based RPG "layer" working on top of cocos2d-iphone. I'm using SneakyInput as the input right now, but I've run into a bit of a snag. Initially, I followed Steffen Itterheim's book and Ray Wenderlich's tutorial, and I got jumpy movement working. My player now moves from tile to tile, without any animation whatsoever. So, I took it a step further. I changed my player.position to a CCMoveTo action. Combined with CCfollow, my player moves pretty smoothly. Here's the problem, though: Between each CCMoveTo, the movement stops, so there's a bit of a jumpiness introduced between movements. To deal with that, I changed my CCmoveTo into a CCMoveBy, and instead of running it once, I decided to have it CCRepeatForever. My plan was to stop the repeating action whenever the player changed directions or released the d-pad. However, when the movement stops, the player is not necessarily centered along the tiles, as it should be. To correctly position the player, I use a CCMoveTo and get the closest position that would put the player back into the proper position. This reintroduces an earlier problem of jumpiness between actions. What is the correct way to implement a smooth joystick while smoothly animating the player and keeping it on the "grid" of tiles? Edit: It turns out that this was caused by a "Bug Fix" in the cocos2d engine.

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  • Compiling SDL under Windows with sdl-config

    - by DarrenVortex
    I have downloaded NXEngine (The Open Source version of Cave Story). I have a make file in the directory, which I execute using msys. However, the make file uses sdl-config: g++ -g -O2 -c main.cpp -D DEBUG `sdl-config --cflags` -Wreturn-type -Wformat -Wno-multichar -o main.o /bin/sh: sdl-config: command not found And apparently sdl-config does not exist under windows since there's no sdl installation. There's also no documentation on the official sourceforge website about this! What do I do?

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  • Keeping crosshairs & GUI onscreen - SFML

    - by nihohit
    I read this question, but didn't understand the implementation suggestions with SFML on c#. For example, right now I'm just trying to make sure that the mouse crosshairs stay onscreen constatnly. I tried using this code: View lastView = this._mainWindow.GetView(); this._mainWindow.SetView(this._mainWindow.DefaultView); this._mainWindow.Draw(crosshair); this._mainWindow.SetView(lastView); after drawing all other sprites and before call this._mainWindow.display(), when beforehand I set crosshair.Position based on its position relative to the window, not the view. This just keeps the screen locked and prevents screen scrolling. Any suggestions?

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  • Visualize flowchart diagram with multiple end symbols

    - by platzhirsch
    I am looking for a standardize way to visualize the following hierarchical logic: The state of the thread is represented by the answers to the hierarchical set of question You can read this listing like a flowchart, you iterate over the questions decide, go one step deeper and so on. Therefore I thought the best way to visualize it, using a flowchart. The problem is, in this hierarchical set it is possible to end in more than one state and its totally valid. I have never seen a flowchart where you can enter more than one state. Is it still possible and I am missing the right symbol to present this logic or are flowchart not fitting anyway? What other graphical representation could I use, is there something fitting in UML? A non-deterministic state machine seems not to be intuitive enough, transfering it into a deterministic state machine would result in to many states, and so on.

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