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  • Having the same texture data in different ID3D11Texture2D

    - by bdmnd
    Sorry if this has been answered elsewhere - I'm rather new to DX. My question concerns conservation of resources - specifically textures in VRAM. I assume that upon returning from a call to CreateTexture2D, a copy of any textures data supplied has been copied elsewhere, likely VRAM. Does DX11 have any facility for having multiple ID3D11Texture2D objects which point to the same data? This might at first seem silly, but imagine a ID3D11Texture2D which is an array of textures. In one material, an artist has chosen to blend three identically sized maps, saved on disk as A.dds, B.dds, and C.dds. Then imagine they have another material which also uses three maps, but this time A.dds, B.dds, and D.dds. The shader code knows the diffuse texture is a texture array, and also has the number of layers baked (three in each case). I would essentially like to set up just two ID3D11Texture2D objects, one for each material, but I don't want to waste VRAM for two identical copies of A.dds and B.dds. I could use explicit texture arrays, of course, but this reduces the number of resources available to the shader and can complicate code somewhat more than would otherwise be needed.

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  • Prevent collisions between mobs/npcs/units piloted by computer AI : How to avoid mobile obstacles?

    - by Arthur Wulf White
    Lets says we have character a starting at point A and character b starting at point B. character a is headed to point B and character b is headed to point A. There are several simple ways to find the path(I will be using Dijkstra). The question is, how do I take preventative action in the code to stop the two from colliding with one another? case2: Characters a and b start from the same point in different times. Character b starts later and is the faster of the two. How do I make character b walk around character a without going through it? case3:Lets say we have m such characters in each side and there is sufficient room to pass through without the characters overlapping with one another. How do I stop the two groups of characters from "walking on top of one another" and allow them pass around one another in a natural organic way. A correct answer would be any algorithm, that given the path to the destination and a list of mobile objects that block the path, finds an alternative path or stops without stopping all units when there is sufficient room to traverse.

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  • Java 2D World question

    - by Munkybunky
    I have a 2D world background made up of a Grid of graphics, which I display on screen with a viewport (800x600) and it all works. My question is I have the following code to convert the mouse co-ordinates to world co-ordinates then World co-ordinates to grid co-ordinates then grid co-ordinates to screen co-ordinates. //Add camerax to mouse screen co-ords to convert to world co-ords. int cursorx_world=(int)camerax+(int)GameInput.mousex; int cursorx_grid=(int)cursorx_world/blocksize; // World Co-ords / gridsize give grid co-ords int cursorx_screen=-(int)camerax+(cursorx_grid*blocksize); So is there anyway I can convert straight from mouse screen co-ords to screen co-ordinates?

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  • System hangs at glReadPixel call with GL_TEXTURE_2D_ARRAY for texturing

    - by Roshan
    I am calling glReadPixel after glDrawArray call. I am rendering a geometry with 3D texture on it as a target GL_TEXTURE_2D_ARRAY. My systems hangs at glreadpixel call. When i use target as GL_TEXTURE_3D the issue does not occurs and it correctly reads the framebuffer contents. glReadPixels(0, 0, GetViewportWidth(), GetViewportHeight(), GL_RGBA, GL_UNSIGNED_BYTE, (GLvoid *)rendered_pixels); I am using SNORM textures with GL_byte data in glTeximage3D call and I am not calling glPixelStorei, is it because of this? What should be the parameter for pixelstore call?

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  • BoundingBox Intersection Problems

    - by Deukalion
    When I try to render two cubes, same sizes, one beside the other. With the same proportions (XYZ). My problem is, why do a Box1.BoundingBox.Contains(Box2.BoundingBox) == ContaintmentType.Intersects - when it clearly doesn't? I'm trying to place objects with BoundingBoxes as "intersection" checking, but this simple example clearly shows that this doesn't work. Why is that? I also try checking height of the next object to be placed, by checking intersection, adding each boxes height += (Max.Y - Min.Y) to a Height value, so when I add a new Box it has a height value. This works, but sometimes due to strange behavior it adds extra values when there isn't anything there. This is an example of what I mean: BoundingBox box1 = GetBoundaries(new Vector3(0, 0, 0), new Vector3(128, 64, 128)); BoundingBox box2 = GetBoundaries(new Vector3(128, 0, 0), new Vector3(128, 64, 128)); if (box1.Contains(box2) == ContainmentType.Intersects) { // This will be executed System.Windows.Forms.MessageBox.Show("Intersects = True"); } if (box1.Contains(box2) == ContainmentType.Disjoint) { System.Windows.Forms.MessageBox.Show("Disjoint = True"); } if (box1.Contains(box2) == ContainmentType.Contains) { System.Windows.Forms.MessageBox.Show("Contains = True"); } Test Method: public BoundingBox GetBoundaries(Vector3 position, Vector3 size) { Vector3[] vertices = new Vector3[8]; vertices[0] = position + new Vector3(-0.5f, 0.5f, -0.5f) * size; vertices[1] = position + new Vector3(-0.5f, 0.5f, 0.5f) * size; vertices[2] = position + new Vector3(0.5f, 0.5f, -0.5f) * size; vertices[3] = position + new Vector3(0.5f, 0.5f, 0.5f) * size; vertices[4] = position + new Vector3(-0.5f, -0.5f, -0.5f) * size; vertices[5] = position + new Vector3(-0.5f, -0.5f, 0.5f) * size; vertices[6] = position + new Vector3(0.5f, -0.5f, -0.5f) * size; vertices[7] = position + new Vector3(0.5f, -0.5f, 0.5f) * size; return BoundingBox.CreateFromPoints(vertices); } Box 1 should start at x -64, Box 2 should start at x 64 which means they never overlap. If I add Box 2 to 129 instead it creates a small gap between the cubes which is not pretty. So, the question is how can I place two cubes beside eachother and make them understand that they do not overlap or actually intersect? Because this way I can never automatically check for intersections or place cube beside eachother.

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  • Rotating a Quad around it center

    - by Trixmix
    How can you rotate a quad around its center? This is what im trying to do but it aint working: GL11.glTranslatef(x-getWidth()/2, y-getHeight()/2, 0); GL11.glRotatef(30, 0.0f, 0.0f, 1.0f); GL11.glTranslatef(x+getWidth()/2, y+getHeight()/2, 0); DRAW my main problem is that it renders it off the screen.. draw code: GL11.glBegin(GL11.GL_QUADS); { GL11.glTexCoord2f(0, 0); GL11.glVertex2f(0, 0); GL11.glTexCoord2f(0, getTexture().getHeight()); GL11.glVertex2f(0, height); GL11.glTexCoord2f(getTexture().getWidth(), getTexture().getHeight()); GL11.glVertex2f(width,height); GL11.glTexCoord2f(getTexture().getWidth(), 0); GL11.glVertex2f(width,0); } GL11.glEnd();

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  • Animations not accepted in animator

    - by Lautaro
    In the official Unity Animator State Machine tutorial video animation clips are dragged out from the assets folder into the animator and dropped. I have a 3D model that i bought online to experiment with that comes with animations. I added a custom made animation as well. These all work well in my demo project. But when i add a animator to the assets and try to drag and drop animations onto it it doesnt work. I get a forbidden-sign as a mouse pointer. I try to add animations through the inspector but that does not work either. The tutorials makes it seem so easy and does not talk anything about what animations can be used. What am i doing wrong?

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  • Information about rendering, batches, the graphical card, performance etc. + XNA?

    - by Aidiakapi
    I know the title is a bit vague but it's hard to describe what I'm really looking for, but here goes. When it comes to CPU rendering, performance is mostly easy to estimate and straightforward, but when it comes to the GPU due to my lack of technical background information, I'm clueless. I'm using XNA so it'd be nice if theory could be related to that. So what I actually wanna know is, what happens when and where (CPU/GPU) when you do specific draw actions? What is a batch? What influence do effects, projections etc have? Is data persisted on the graphics card or is it transferred over every step? When there's talk about bandwidth, are you talking about a graphics card internal bandwidth, or the pipeline from CPU to GPU? Note: I'm not actually looking for information on how the drawing process happens, that's the GPU's business, I'm interested on all the overhead that precedes that. I'd like to understand what's going on when I do action X, to adapt my architectures and practices to that. Any articles (possibly with code examples), information, links, tutorials that give more insight in how to write better games are very much appreciated. Thanks :)

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  • How to detect collisions between sprite and a user generated shape of some sort?

    - by Huwell
    How to detect a collision between a sprite and a user generated shape of some sort. For example. There are some objects on the screen. The user takes their finger and draws an circle shape around a object (The selection rule is painting circle around the sprite, but the painting shapes may be various). I need to detect which object selected, which just like: (demo images) http://i52.tinypic.com/28h0t1g.png

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  • Do I need the 'w' component in my Vector class?

    - by bobobobo
    Assume you're writing matrix code that handles rotation, translation etc for 3d space. Now the transformation matrices have to be 4x4 to fit the translation component in. However, you don't actually need to store a w component in the vector do you? Even in perspective division, you can simply compute and store w outside of the vector, and perspective divide before returning from the method. For example: // post multiply vec2=matrix*vector Vector operator*( const Matrix & a, const Vector& v ) { Vector r ; // do matrix mult r.x = a._11*v.x + a._12*v.y ... real w = a._41*v.x + a._42*v.y ... // perspective divide r /= w ; return r ; } Is there a point in storing w in the Vector class?

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  • How to adjust the shooting angle of an object

    - by Blue
    I've been trying to add an angle adjustment feature to a power bar that I got from unity3dStudents. But I can't seem to get the code right. I'm using addforce to rigidbody, it works but the power is too great. I also found that rotating the object it's shooting from changes the angle. But I don't know how to proceed from that. Can somebody show me the problem with the script below, as in how to add height to the addforce without it going to far up or to the side? Or how to change the angle of the object? var theAngle : int; var maxAngle : int = 130; var minAngle : int = 0; var angleIncreasing : boolean = false; var angleDecreasing : boolean = false; var rotationSpeed : float = 10; var ball : Rigidbody; var spawnPos : Transform; var shotForce : float = 25; function Update () { if(Input.GetKeyDown("k")){ angleIncreasing = true; angleDecreasing = false; } if(Input.GetKeyUp("k")){ angleIncreasing = false; } if(Input.GetKeyDown("l")){ angleIncreasing = false; angleDecreasing = true; } if(Input.GetKeyUp("l")){ angleDecreasing = false; } ------- if(angleIncreasing){ theAngle += Time.deltaTime * rotationSpeed; if(theAngle > maxAngle){ theAngle = maxAngle; } } if(angleDecreasing){ theAngle -= Time.deltaTime * rotationSpeed; if(theAngle < minAngle){ theAngle = minAngle; } } } function Shoot(power : float, angle : int){ ---- var forward : Vector3 = spawnPos.forward; var upward : Vector3 = spawnPos.up; pFab.AddForce(forward * power * shotForce); pFab.AddForce(upward * angle * 10); ---- }

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  • infer half vector length in BRDF

    - by cician
    it's my first question on stack. Is it possible to infer length of the half angle vector for specular lighting from N·L and N·V without the whole view and light vectors? I may be completely off-track, but I have this gut feeling it's possible... Why? I'm working on a skin shader and I'm already doing one texture lookup with N·L+N·E and one texture lookup for specular with N·H+N·V. The latter one can be transformed into N·L+N·E lookup if only I had the half vector length. Doing so could simplify the shader a bit and move some operations into the pre-computed lookup texture. It would make a huge difference since I'm trying to squeeze as much functionality as possible to a single pass mobile version so instruction count matters. Thanks.

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  • Algorithm for procedural city generation?

    - by Zove Games
    I am planning on making a (simple) procedural city generator using Java. I need ideas on whan algorithm to use for the layout, and the actual buildings. The city will mostly have skyscrapers, not really much complex stuff. For the layout I already have a simple algorithm implemented: Create a Map with java.awt.Point keys and Integer values. Fill it with all the points in the city's bounds with the value as -1 (unnassigned) Shuffle the map, and assign the 1st 10 of the keys IDs (from 1-10) Loop until all points have IDs: Loop though all points: Assign points next to an assigned point IDs of the point next to them, if 2 or more points border the point, then randomly choose which ID the point will get. You will end up with 10 random regions. Make roads bordering these regions. Fill the inside of each region with a randomly spaced and randomly rotated grid PROBLEM: This is not the fastest way to do it. What algorithm should I use for the layout. And what should I use to make each building's design? I don't even know how I'm going to do that yet (fractals maybe). I just need some ideas, not actual code.

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  • How effects found in "Autodesk Fluid FX" are implemented using OpenGL ES?

    - by afds
    How this kind of effects are technically implemented using OpenGL ES? Are they performing simulation on GPU (using Shaders) or CPU while using some smart vertex positioning and texturing? Why it appears so fast (in terms of performance)? You might check the video of that app here: http://www.youtube.com/watch?v=F4KOk6QP6kQ edit Here is the presentation for the app: http://www.futuregameon.com/FGO2010_JosStam.pdf

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  • Is this the most effect simple way to display a moving image? SDL2

    - by user36324
    I've looked around for tutorials on SDL2, but there isnt many so I am curious i was messing around and is this an effective way to move an image. One problem is that it drags along the image to where it moves. #include "SDL.h" #include "SDL_image.h" int main(int argc, char* argv[]) { bool exit = false; SDL_Init(SDL_INIT_EVERYTHING); SDL_Window *win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN); SDL_Renderer *ren = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC); SDL_Surface *png = IMG_Load("character.png"); SDL_Rect src; src.x = 0; src.y = 0; src.w = 161; src.h = 159; SDL_Rect dest; dest.x = 50; dest.y = 50; dest.w = 161; dest.h = 159; SDL_Texture *tex = SDL_CreateTextureFromSurface(ren, png); SDL_FreeSurface(png); while(exit==false){ dest.x++; SDL_RenderClear(ren); SDL_RenderCopy(ren, tex, &src, &dest); SDL_RenderPresent(ren); } SDL_Delay(5000); SDL_DestroyTexture(tex); SDL_DestroyRenderer(ren); SDL_DestroyWindow(win); SDL_Quit(); }

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  • Are there any reasons to use Legacy (2.X) OpenGL?

    - by user27886
    The benefits are well documented of the Modern OpenGL 3.X & 4.X API's, but I'm wondering if there are ANY benefits to keeping with the old OpenGL, Or if learning OpenGL 2.X is a complete waste of time now no matter what? Particularly I've wondered if using the OpenGL 2.X API is appropriate if the target platform had graphics hardware capable of only up to OpenGL 2.X. Would a driver update on said target platform allow programs compiled using the Modern OpenGL API's to be released on this old platform? If they both work, which would be faster? Thanks

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  • Point in Polygon, Ray Method: ending infinite line

    - by user2878528
    Having a bit of trouble with point in polygon collision detection using the ray method i.e. http://en.wikipedia.org/wiki/Point_in_polygon My problem is I need to give an end to the infinite line created. As with this infinite line I always get an even number of intersections and hence an invalid result. i.e. ignore or intersection to the right of the point being checked what I have what I want My current code based of Mecki awesome response for (int side = 0; side < vertices.Length; side++) { // Test if current side intersects with ray. // create infinite line // See: http://en.wikipedia.org/wiki/Linear_equation a = end_point.Y - start_point.Y; b = start_point.X - end_point.X; c = end_point.X * start_point.Y - start_point.X * end_point.Y; //insert points of vector d2 = a * vertices[side].Position.X + b * vertices[side].Position.Y + c; if (side - 1 < 0) d1 = a * vertices[vertices.Length - 1].Position.X + b * vertices[vertices.Length - 1].Position.Y + c; else d1 = a * vertices[side-1].Position.X + b * vertices[side-1].Position.Y + c; // If points have opposite sides, intersections++; if (d1 > 0 && d2 < 0 ) intersections++; if (d1 < 0 && d2 > 0 ) intersections++; } //if intersections odd inside = true if ((intersections % 2) == 1) inside = true; else inside = false;

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  • RasterizerState set to null after calling DrawText in Nuclex

    - by ProgrammerAtWork
    I have the following code in XNA: // class members Text t1; Text t2; Text t3; // init // Debugfont is size 24 vectorfont t1 = MM.DebugFont24.Fill("hello"); t1 = MM.DebugFont24.Extrude("hello"); t2 = MM.DebugFont24.Fill("hello"); t2 = MM.DebugFont24.Extrude("hello"); t3 = MM.DebugFont24.Fill("hello"); t3 = MM.DebugFont24.Extrude("hello"); // Draw TextBatch test = new TextBatch(MM.GD); test.DrawText(t1, Color.Red); test.DrawText(t2, Color.Red); test.DrawText(t3, Color.Red); test.End(); //After the second call to the TextBatch, RasterizerState of the GraphicsDevice is set to null //But I don't get any runtime errors or any indication of that something is wrong. Is this supposed to happen? Or am I doing something wrong? I've discovered that this happened because culling was set to None when I was rendering textures

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  • Procedural Planets, Heightmaps and Textures

    - by henryprescott
    I am currently working on an OpenGL procedural planet generator. I hope to use it for a space RPG, that will not allow players to go down to the surface of a planet so I have ignored anything ROAM related. At the momement I am drawing a cube with VBOs and mapping onto a sphere. I am familiar with most fractal heightmap generating techniques and have already implemented my own version of midpoint displacement(not that useful in this case I know). My question is, what is the best way to procedurally generate the heightmap. I have looked at libnoise which allows me to make tilable heightmaps/textures, but as far as I can see I would need to generate a net like this. Leaving the tiling obvious. Could anyone advise me on the best route to take? Any input would be much appreciated. Thanks, Henry.

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  • Are these non-standard applications of rendering practical in games?

    - by maul
    I've recently got into 3D and I came up with a few different "tricky" rendering techniques. Unfortunately I don't have the time to work on this myself, but I'd like to know if these are known methods and if they can be used in practice. Hybrid rendering Now I know that ray-tracing is still not fast enough for real-time rendering, at least on home computers. I also know that hybrid rendering (a combination of rasterization and ray-tracing) is a well known theory. However I had the following idea: one could separate a scene into "important" and "not important" objects. First you render the "not important" objects using traditional rasterization. In this pass you also render the "important" objects using a special shader that simply marks these parts on the image using a special color, or some stencil/depth buffer trickery. Then in the second pass you read back the results of the first pass and start ray tracing, but only from the pixels that were marked by the "important" object's shader. This would allow you to only ray-trace exactly what you need to. Could this be fast enough for real-time effects? Rendered physics I'm specifically talking about bullet physics - intersection of a very small object (point/bullet) that travels across a straight line with other, relatively slow-moving, fairly constant objects. More specifically: hit detection. My idea is that you could render the scene from the point of view of the gun (or the bullet). Every object in the scene would draw a different color. You only need to render a 1x1 pixel window - the center of the screen (again, from the gun's point of view). Then you simply check that central pixel and the color tells you what you hit. This is pixel-perfect hit detection based on the graphical representation of objects, which is not common in games. Afaik traditional OpenGL "picking" is a similar method. This could be extended in a few ways: For larger (non-bullet) objects you render a larger portion of the screen. If you put a special-colored plane in the middle of the scene (exactly where the bullet will be after the current frame) you get a method that works as the traditional slow-moving iterative physics test as well. You could simulate objects that the bullet can pass through (with decreased velocity) using alpha blending or some similar trick. So are these techniques in use anywhere, and/or are they practical at all?

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  • GLSL per pixel lighting with custom light type

    - by Justin
    Ok, I am having a big problem here. I just got into GLSL yesterday, so the code will be terrible, I'm sure. Basically, I am attempting to make a light that can be passed into the fragment shader (for learning purposes). I have four input values: one for the position of the light, one for the color, one for the distance it can travel, and one for the intensity. I want to find the distance between the light and the fragment, then calculate the color from there. The code I have gives me a simply gorgeous ring of light that get's twisted and widened as the matrix is modified. I love the results, but it is not even close to what I am after. I want the light to be moved with all of the vertices, so it is always in the same place in relation to the objects. I can easily take it from there, but getting that to work seems to be impossible with my current structure. Can somebody give me a few pointers (pun not intended)? Vertex shader: attribute vec4 position; attribute vec4 color; attribute vec2 textureCoordinates; varying vec4 colorVarying; varying vec2 texturePosition; varying vec4 fposition; varying vec4 lightPosition; varying float lightDistance; varying float lightIntensity; varying vec4 lightColor; void main() { vec4 ECposition = gl_ModelViewMatrix * gl_Vertex; vec3 tnorm = normalize(vec3 (gl_NormalMatrix * gl_Normal)); fposition = ftransform(); gl_Position = fposition; gl_TexCoord[0] = gl_MultiTexCoord0; fposition = ECposition; lightPosition = vec4(0.0, 0.0, 5.0, 0.0) * gl_ModelViewMatrix * gl_Vertex; lightDistance = 5.0; lightIntensity = 1.0; lightColor = vec4(0.2, 0.2, 0.2, 1.0); } Fragment shader: varying vec4 colorVarying; varying vec2 texturePosition; varying vec4 fposition; varying vec4 lightPosition; varying float lightDistance; varying float lightIntensity; varying vec4 lightColor; uniform sampler2D texture; void main() { float l_distance = sqrt((gl_FragCoord.x * lightPosition.x) + (gl_FragCoord.y * lightPosition.y) + (gl_FragCoord.z * lightPosition.z)); float l_value = lightIntensity / (l_distance / lightDistance); vec4 l_color = vec4(l_value * lightColor.r, l_value * lightColor.g, l_value * lightColor.b, l_value * lightColor.a); vec4 color; color = texture2D(texture, gl_TexCoord[0].st); gl_FragColor = l_color * color; //gl_FragColor = fposition; }

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  • Material tiling and offset in unity

    - by Simran kaur
    Ambiguity: What exactly is the difference between Tiling the material and Offset of material? Need to do: I need the material to be repeated n times on the object where I need to set the value of n via script.How do I do it? It seems to happen through Tiling(tried via inspector) but again what is difference between mainTextureOffset and setTextureOffset? Tried: Following is the line of code that I tried to repeat the texture n number of times on an object(repeat across the width of object), but it does nothing significant that I can see.

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  • 2d ball collision code problem XNA, over accelerated balls and stick together sometimes. help please? [closed]

    - by Sivan
    public static void Collision(Ball ball1, Ball ball2) { Vector3 x = new Vector3((ball1.BallPosition.X - ball2.BallPosition.X), (ball1.BallPosition.Y - ball2.BallPosition.Y), 0); x.Normalize(); Vector3 v1 = new Vector3(ball1.Speed, 0); float x1 = Vector3.Dot(x, v1); Vector3 v1x = x * x1; Vector3 v1y = v1 - v1x; x = -x; Vector3 v2 = new Vector3(ball2.Speed, 0); float x2 = Vector3.Dot(x, v2); Vector3 v2x = x * x2; Vector3 v2y = v2 - v2x; float m1 = 12, m2 = 4; float combinedMass = m1 + m2; Vector3 newVelA = (v1x * ((m1 - m2) / combinedMass)) + (v2x * ((2f * m2) / combinedMass)) + v1y; Vector3 newVelB = (v1x * ((2f * m1) / combinedMass)) + (v2x * ((m2 - m1) / combinedMass)) + v2y; ball1.Speed = new Vector2(newVelA.X, newVelA.Y); ball2.Speed = new Vector2(newVelB.X,newVelB.Y ); }

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  • Open Source Analysis

    - by BluFire
    There are a lot of code in open source projects, looking at all of the code is time consuming and can be confusing to a novice like me. Are there any sections of open-source projects that should be focused on? What should I focus on when I look at code? I'm asking this in general because if I ask this specifically, the question will only apply in one or two projects rather than an entire group of projects ranging in different types of games and difficulty.

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  • In 3D camera math, calculate what Z depth is pixel unity for a given FOV

    - by badweasel
    I am working in iOS and OpenGL ES 2.0. Through trial and error I've figured out a frustum to where at a specific z depth pixels drawn are 1 to 1 with my source textures. So 1 pixel in my texture is 1 pixel on the screen. For 2d games this is good. Of course it means that I also factor in things like the size of the quad and the size of the texture. For example if my sprite is a quad 32x32 pixels. The quad size is 3.2 units wide and tall. And the texcoords are 32 / the size of the texture wide and tall. Then the frustum is: matrixFrustum(-(float)backingWidth/frustumScale,(float)backingWidth/frustumScale, -(float)backingHeight/frustumScale, (float)backingHeight/frustumScale, 40, 1000, mProjection); Where frustumScale is 800 for a retina screen. Then at a distance of 800 from camera the sprite is pixel for pixel the same as photoshop. For 3d games sometimes I still want to be able to do this. But depending on the scene I sometimes need the FOV to be different things. I'm looking for a way to figure out what Z depth will achieve this same pixel unity for a given FOV. For this my mProjection is set using: matrixPerspective(cameraFOV, near, far, (float)backingWidth / (float)backingHeight, mProjection); With testing I found that at an FOV of 45.0 a Z of 38.5 is very close to pixel unity. And at an FOV of 30.0 a Z of 59.5 is about right. But how can I calculate a value that is spot on? Here's my matrixPerspecitve code: void matrixPerspective(float angle, float near, float far, float aspect, mat4 m) { //float size = near * tanf(angle / 360.0 * M_PI); float size = near * tanf(degreesToRadians(angle) / 2.0); float left = -size, right = size, bottom = -size / aspect, top = size / aspect; // Unused values in perspective formula. m[1] = m[2] = m[3] = m[4] = 0; m[6] = m[7] = m[12] = m[13] = m[15] = 0; // Perspective formula. m[0] = 2 * near / (right - left); m[5] = 2 * near / (top - bottom); m[8] = (right + left) / (right - left); m[9] = (top + bottom) / (top - bottom); m[10] = -(far + near) / (far - near); m[11] = -1; m[14] = -(2 * far * near) / (far - near); } And my mView is set using: lookAtMatrix(cameraPos, camLookAt, camUpVector, mView); * UPDATE * I'm going to leave this here in case anyone has a different solution, can explain how they do it, or why this works. This is what I figured out. In my system I use a 10th scale unit to pixels on non-retina displays and a 20th scale on retina displays. The iPhone is 640 pixels wide on retina and 320 pixels wide on non-retina (obsolete). So if I want something to be the full screen width I divide by 20 to get the OpenGL unit width. Then divide that by 2 to get the left and right unit position. Something 32 units wide centered on the screen goes from -16 to +16. Believe it or not I have an excel spreadsheet do all this math for me and output all the vertex data for my sprite sheet. It's an arbitrary thing I made up to do .1 units = 1 non-retina pixel or 2 retina pixels. I could have made it .01 units = 2 pixels and someday I might switch to that. But for now it's the other. So the width of the screen in units is 32.0, and that means the left most pixel is at -16.0 and the right most is at 16.0. After messing a bit I figured out that if I take the [0] value of an identity modelViewProjection matrix and multiply it by 16 I get the depth required to get 1:1 pixels. I don't know why. I don't know if the 16 is related to the screen size or just a lucky guess. But I did a test where I placed a sprite at that calculated depth and varied the FOV through all the valid values and the object stays steady on screen with 1:1 pixels. So now I'm just calculating the unityDepth that way. If someone gives me a better answer I'll checkmark it.

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