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  • Mapping a Vertex Buffer in DirectX11

    - by judeclarke
    I have a VertexBuffer that I am remapping on a per frame base for a bunch of quads that are constantly updated, sharing the same material\index buffer but have different width/heights. However, currently right now there is a really bad flicker on this geometry. Although it is flickering, the flicker looks correct. I know it is the vertex buffer mapping because if I recreate the entire VB then it will render fine. However, as an optimization I figured I would just remap it. Does anyone know what the problem is? The length (width, size) of the vertex buffer is always the same. One might think it is double buffering, however, it would not be double buffering because it only happens when I map/unmap the buffer, so that leads me to believe that I am setting some parameters wrong on the creation or mapping. I am using DirectX11, my initialization and remap code are: Initialization code D3D11_BUFFER_DESC bd; ZeroMemory( &bd, sizeof(bd) ); bd.Usage = D3D11_USAGE_DYNAMIC; bd.ByteWidth = vertCount * vertexTypeWidth; bd.BindFlags = D3D11_BIND_VERTEX_BUFFER; //bd.CPUAccessFlags = 0; bd.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE; D3D11_SUBRESOURCE_DATA InitData; ZeroMemory( &InitData, sizeof(InitData) ); InitData.pSysMem = vertices; mVertexType = vertexType; HRESULT hResult = device->CreateBuffer( &bd, &InitData, &m_pVertexBuffer ); // This will be S_OK if(hResult != S_OK) return false; Remap code D3D11_MAPPED_SUBRESOURCE resource; HRESULT hResult = deviceContext->Map(m_pVertexBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &resource); // This will be S_OK if(hResult != S_OK) return false; resource.pData = vertices; deviceContext->Unmap(m_pVertexBuffer, 0);

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  • Order of operations to render VBO to FBO texture and then rendering FBO texture full quad

    - by cyberdemon
    I've just started using OpenGL with C# via the OpenTK library. I've managed to successfully render my game world using VBOs. I now want to create a pixellated affect by rendering the frame to an offscreen FBO with a size half of my GameWindow size and then render that FBO to a full screen quad. I've been looking at the OpenTK example here: http://www.opentk.com/doc/graphics/frame-buffer-objects ...but the result is a black form. I'm not sure which parts of the example code belongs in the OnLoad event and OnRenderFrame. Can someone please tell me if the below code shows the correct order of operations? OnLoad { // VBO. // DataArrayBuffer GenBuffers/BindBuffer/BufferData // ElementArrayBuffer GenBuffers/BindBuffer/BufferData // ColourArrayBuffer GenBuffers/BindBuffer/BufferData // FBO. // ColourTexture GenTextures/BindTexture/TexParameterx4/TexImage2D // Create FBO. // Textures Ext.GenFramebuffers/Ext.BindFramebuffer/Ext.FramebufferTexture2D/Ext.FramebufferRenderbuffer } OnRenderFrame { // Use FBO buffer. Ext.BindFramebuffer(FBO) GL.Clear // Set viewport to FBO dimensions. GL.DrawBuffer((DrawBufferMode)FramebufferAttachment.ColorAttachment0Ext) // Bind VBO arrays. GL.BindBuffer(ColourArrayBuffer) GL.ColorPointer GL.EnableClientState(ColorArray) GL.BindBuffer(DataArrayBuffer) // If world changed GL.BufferData(DataArrayBuffer) GL.VertexPointer GL.EnableClientState(VertexArray) GL.BindBuffer(ElementArrayBuffer) // Render VBO. GL.DrawElements // Bind visible buffer. GL.Ext.BindFramebuffer(0) GL.DrawBuffer(Back) GL.Clear // Set camera to view texture. GL.BindTexture(ColourTexture) // Render FBO texture GL.Begin(Quads) // Draw texture on quad // TexCoord2/Vertex2 GL.End SwapBuffers }

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  • OpenGL CPU vs. GPU

    - by Nitrex88
    So I've always been under the impression that doing work on the GPU is always faster than on the CPU. Because of this, in OpenGL, I usually try to do intensive tasks in shaders so they get the speed boost from the GPU. However, now I'm starting to realize that some things simply work better on the CPU and actually perform worse on the GPU (particularly when a geometry shader is involved). For example, in a recent project I did involving procedurally generated terrain, I tried passing a grid of single triangles into a geometry shader, and tesselated each of these triangles into quads with 400 vertices whose height was determined by a noise function. This worked fine, and looked great, but easily maxed out the GPU with only 25 base triangles and caused a very slow framerate. I then discovered that tesselating on the CPU instead, and setting the height (using noise function) in the vertex shader was actually faster! This prompted me to question the benefits of using the GPU as much as possible... So, I was wondering if someone could describe the general pros and cons of using the GPU vs CPU for intensive graphics tasks. I know this mainly comes down to what your trying to achieve, so if necessary, use the above scenario to discuss why the "CPU + vertex shader" was actually faster than doing everything in the geometry shader on the GPU. It's possible my hardware (newest macbook pro) isn't optomized well for the geometry shader (thus causing the slow framerate). Also, I read that the vertex shader is very good with parallelism, and would love a quick explanation of how this may have played a role in speeding up my procedural terrain. Any info/advice about CPU/GPU/shaders would be awesome!

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  • OpenGL CPU vs. GPU

    - by Nitrex88
    So I've always been under the impression that doing work on the GPU is always faster than on the CPU. Because of this, in OpenGL, I usually try to do intensive tasks in shaders so they get the speed boost from the GPU. However, now I'm starting to realize that some things simply work better on the CPU and actually perform worse on the GPU (particularly when a geometry shader is involved). For example, in a recent project I did involving procedurally generated terrain, I tried passing a grid of single triangles into a geometry shader, and tesselated each of these triangles into quads with 400 vertices whose height was determined by a noise function. This worked fine, and looked great, but easily maxed out the GPU with only 25 base triangles and caused a very slow framerate. I then discovered that tesselating on the CPU instead, and setting the height (using noise function) in the vertex shader was actually faster! This prompted me to question the benefits of using the GPU as much as possible... So, I was wondering if someone could describe the general pros and cons of using the GPU vs CPU for intensive graphics tasks. I know this mainly comes down to what your trying to achieve, so if necessary, use the above scenario to discuss why the "CPU + vertex shader" was actually faster than doing everything in the geometry shader on the GPU. It's possible my hardware (newest macbook pro) isn't optomized well for the geometry shader (thus causing the slow framerate). Also, I read that the vertex shader is very good with parallelism, and would love a quick explanation of how this may have played a role in speeding up my procedural terrain. Any info/advice about CPU/GPU/shaders would be awesome!

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  • How to blend multiple normal maps?

    - by János Turánszki
    I want to achieve a distortion effect which distorts the full screen. For that I spawn a couple of images with normal maps. I render their normal map part on some camera facing quads onto a rendertarget which is cleared with the color (127,127,255,255). This color means that there is no distortion whatsoever. Then I want to render some images like this one onto it: If I draw one somewhere on the screen, then it looks correct because it blends in seamlessly with the background (which is the same color that appears on the edges of this image). If I draw another one on top of it then it will no longer be a seamless transition. For this I created a blendstate in directX 11 that keeps the maximum of two colors, so it is now a seamless transition, but this way, the colors lower than 127 (0.5f normalized) will not contribute. I am not making a simulation and the effect looks quite convincing and nice for a game, but in my spare time I am thinking how I could achieve a nicer or a more correct effect with a blend state, maybe averaging the colors somehow? I I did it with a shader, I would add the colors and then I would normalize them, but I need to combine arbitrary number of images onto a rendertarget. This is my blend state now which blends them seamlessly but not correctly: D3D11_BLEND_DESC bd; bd.RenderTarget[0].BlendEnable=true; bd.RenderTarget[0].SrcBlend = D3D11_BLEND_SRC_ALPHA; bd.RenderTarget[0].DestBlend = D3D11_BLEND_INV_SRC_ALPHA; bd.RenderTarget[0].BlendOp = D3D11_BLEND_OP_MAX; bd.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND_ONE; bd.RenderTarget[0].DestBlendAlpha = D3D11_BLEND_ZERO; bd.RenderTarget[0].BlendOpAlpha = D3D11_BLEND_OP_MAX; bd.RenderTarget[0].RenderTargetWriteMask = 0x0f; Is there any way of improving upon this? (PS. I considered rendering each one with a separate shader incementally on top of each other but that would consume a lot of render targets which is unacceptable)

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  • Seeking an C/C++ OBJ geometry read/write that does not modify the representation

    - by Blake Senftner
    I am seeking a means to read and write OBJ geometry files with logic that does not modify the geometry representation. i.e. read geometry, immediately write it, and a diff of the source OBJ and the one just written will be identical. Every OBJ writing utility I've been able to find online fails this test. I am writing small command line tools to modify my OBJ geometries, and I need to write my results, not just read the geometry for rendering purposes. Simply needing to write the geometry knocks out 95% of the OBJ libraries on the web. Also, many of the popular libraries modify the geometry representation. For example, Nat Robbin's GLUT library includes the GLM library, which both converts quads to triangles, as well as reverses the topology (face ordering) of the geometry. It's still the same geometry, but if your tool chain expects a given topology, such as for rigging or morph targets, then GLM is useless. I'm not rendering in these tools, so dependencies like OpenGL or GLUT make no sense. And god forbid, do not "optimize" the geometry! Redundant vertices are on purpose for maintaining oneself on cache with our weird little low memory mobile devices.

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  • Checking if an object is inside bounds of an isometric chunk

    - by gopgop
    How would I check if an object is inside the bounds of an isometric chunk? for example I have a player and I want to check if its inside the bounds of this isometric chunk. I draw the isometric chunk's tiles using OpenGL Quads. My first try was checking in a square pattern kind of thing: e = object; this = isometric chunk; if (e.getLocation().getX() < this.getLocation().getX()+World.CHUNK_WIDTH*World.TILE_WIDTH && e.getLocation().getX() > this.getLocation().getX()) { if (e.getLocation().getY() > this.getLocation().getY() && e.getLocation().getY() < this.getLocation().getY()+World.CHUNK_HEIGHT*World.TILE_HEIGHT) { return true; } } return false; What happens here is that it checks in a SQUARE around the chunk so not the real isometric bounds. Image example: (THE RED IS WHERE THE PROGRAM CHECKS THE BOUNDS) What I have now: Desired check: Ultimately I want to do the same for each tile in the chunk. EXTRA INFO: Till now what I had in my game is you could only move tile by tile but now I want them to move freely but I still need them to have a tile location so no matter where they are on the tile their tile location will be that certain tile. then when they are inside a different tile's bounding box then their tile location becomes the new tile. Same thing goes with chunks. the player does have an area but the area does not matter in this case. and as long as the X and Y are inside the bounding box then it should return true. they don't have to be completely on the tile.

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  • geomipmapping using displacement mapping (and glVertexAttribDivisor)

    - by Will
    I wake up with a clear vision, but sadly my laptop card doesn't do displacement mapping nor glVertexAttribDivisor so I can't test it out; I'm left sharing here: With geomipmapping, the grid at any factor is transposable - if you pass in an offset - say as a uniform - you can reuse the same vertex and index array again and again. If you also pass in the offset into the heightmap as a uniform, the vertex shader can do displacement mapping. If the displacement map is mipmapped, you get the advantages of trilinear filtering for distant maps. And, if the scenery is closer, rather than exposing that the you have a world made out of quads, you can use your transposable grid vertex array and indices to do vertex-shader interpolation (fancy splines) to do super-smooth infinite zoom? So I have some questions: does it work? In theory, in practice? does anyone do it? Does this technique have a name? Papers, demos, anything I can look at? does glVertexAttribDivisor mean that you can have a single glMultiDrawElementsEXT or similar approach to draw all your terrain tiles in one call rather than setting up the uniforms and emitting each tile? Would this offer any noticeable gains? does a heightmap that is GL_LUMINANCE take just one byte per pixel(=vertex)? (On mainstream cards, obviously. Does storage vary in practice?) Does going to the effort of reusing the same vertices and indices mean that you can basically fill the GPU RAM with heightmap and not a lot else, giving you either bigger landscapes or more detailed landscapes/meshes for the same bang? is mipmapping the displacement map going to work? On future cards? Is it going to introduce unsurmountable inaccuracies if it is enabled?

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  • GLSL billboard move center of rotation

    - by Jacob Kofoed
    I have successfully set up a billboard shader that works, it can take in a quad and rotate it so it always points toward the screen. I am using this vertex-shader: void main(){ vec4 tmpPos = (MVP * bufferMatrix * vec4(0.0, 0.0, 0.0, 1.0)) + (MV * vec4( vertexPosition.x * 1.0 * bufferMatrix[0][0], vertexPosition.y * 1.0 * bufferMatrix[1][1], vertexPosition.z * 1.0 * bufferMatrix[2][2], 0.0) ); UV = UVOffset + vertexUV * UVScale; gl_Position = tmpPos; BufferMatrix is the model-matrix, it is an attribute to support Instance-drawing. The problem is best explained through pictures: This is the start position of the camera: And this is the position, looking in from 45 degree to the right: Obviously, as each character is it's own quad, the shader rotates each one around their own center towards the camera. What I in fact want is for them to rotate around a shared center, how would I do this? What I have been trying to do this far is: mat4 translation = mat4(1.0); translation = glm::translate(translation, vec3(pos)*1.f * 2.f); translation = glm::scale(translation, vec3(scale, 1.f)); translation = glm::translate(translation, vec3(anchorPoint - pos) / vec3(scale, 1.f)); Where the translation is the bufferMatrix sent to the shader. What I am trying to do is offset the center, but this might not be possible with a single matrix..? I am interested in a solution that doesn't require CPU calculations each frame, but rather set it up once and then let the shader do the billboard rotation. I realize there's many different solutions, like merging all the quads together, but I would first like to know if the approach with offsetting the center is possible. If it all seems a bit confusing, it's because I'm a little confused myself.

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  • How to create an Orthographic display in OpenGL (ES) that handles different screen sizes and orientations?

    - by Piku
    I'm trying to create an iPad/iPhone game using GLES2.0 that contains a 3D scene with a heads-up-display/GUI overlaid on the top. However, this problem would also apply if I were to port my game to a computer and run the game in a resizable window, or allow the user to change screen resolutions... When trying to make the 2D GUI/HUD work I've made the assumption that all I'm really doing is drawing a load of 2D textured 'quads' on the screen and am trying to treat the orthographic projection as an old-style 2D display with 0,0 in the upper left and screenWidth,ScreenHeight in the lower right. This causes me all sorts of confusion when I rotate my ipad into Landscape mode since I can't work out what to put into my projection and modelview matrices to turn everything around the right way. It also gets messy if I want to support the iPad's large screen, an iPhone or a Retina display since I have to then draw three sets of textures for everything and work out which ones to use. Should I be trying to map the 2D OpenGL co-ords 1:1 with the screen? While typing out this question it occurs to me that I could keep my origin in the centre, still running -1/+1 along the axes. This would let me scale my 2D content appropriately on the different screen sizes, but wouldn't I end up with the textures being scaled and possibly losing quality? I'm using OpenGLES 2.0 and have a matrix library that has equivalents to the GLES1.1 glOrthof() and glFrustrum() calls.

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  • Strange and erratic transformations when using OpenGL VBOs to render scene

    - by janoside
    I have an existing iOS game with fairly simple scenes (all textured quads) and I'm using Apple's "Texture2D" class. I'm trying to convert this class to use VBOs since the vertices of my objects basically never change so I may as well not re-create them for every object every frame. I have the scene rendering using VBOs but the sizes and orientations of all rendered objects are strange and erratic - though locations seem generally correct. I've been toying with this code for a few days now, and I've found something odd: if I re-create all of my VBOs each frame, everything looks correct, even though I'm almost certain my vertices are not changing. Other notes I'm basing my work on this tutorial, and therefore am also using "IBOs" I create my buffers before rendering begins My buffers include vertex and texture data I'm using OpenGL ES 1.1 Fearing some strange effect of the current matrix GL state at the time of buffer creation I've also tried wrapping my buffer-setup code in a "pushMatrix-loadIdentity-popMatrix" block which (as expected) had no effect I'm aware that various articles have been published demonstrating that VBOs may not help performance, but I want to understand this problem and at least have the option to use them. I realize this is a shot in the dark, but has anyone else experienced this type of strange behavior? What might I be doing to result in this behavior? It's rather difficult for me to isolate the problem since I'm working in an existing, moderately complex project, so suggestions about how to approach the problem are also quite welcome.

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  • OpenGL sprites and point size limitation

    - by Srdan
    I'm developing a simple particle system that should be able to perform on mobile devices (iOS, Andorid). My plan was to use GL_POINT_SPRITE/GL_PROGRAM_POINT_SIZE method because of it's efficiency (GL_POINTS are enough), but after some experimenting, I found myself in a trouble. Sprite size is limited (to usually 64 pixels). I'm calculating size using this formula gl_PointSize = in_point_size * some_factor / distance_to_camera to make particle sizes proportional to distance to camera. But at some point, when camera is close enough, problem with size limitation emerges and whole system starts looking unrealistic. Is there a way to avoid this problem? If no, what's alternative? I was thinking of manually generating billboard quad for each particle. Now, I have some questions about that approach. I guess minimum geometry data would be four vertices per particle and index array to make quads from these vertices (with GL_TRIANGLE_STRIP). Additionally, for each vertex I need a color and texture coordinate. I would put all that in an interleaved vertex array. But as you can see, there is much redundancy. All vertices of same particle share same color value, and four texture coordinates are same for all particles. Because of how glDrawArrays/Elements works, I see no way to optimise this. Do you know of a better approach on how to organise per-particle data? Should I use buffers or vertex arrays, or there is no difference because each time I have to update all particles' data. About particles simulation... Where to do it? On CPU or on a vertex processors? Something tells me that mobile's CPU would do it faster than it's vertex unit (at least today in 2012 :). So, any advice on how to make a simple and efficient particle system without particle size limitation, for mobile device, would be appreciated. (animation of camera passing through particles should be realistic)

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  • how to use opengl blend mode/functions to brighten/darken a texture.

    - by Jigar
    Tried this code, but the texture didnot get any lighter. try { texture = TextureLoader.getTexture("png", Game.class.getResourceAsStream("/brick.png"), true, GL_NEAREST); } catch (IOException e) { e.printStackTrace(); } GL11.glBindTexture(GL11.GL_TEXTURE_2D, texture.getTextureID()); glEnable(GL_BLEND); glBlendFunc(GL_CONSTANT_ALPHA, GL_CONSTANT_ALPHA); GL14.glBlendColor(1.0f, 1.0f, 1.0f, 0.5f); glColor4f(1, 1, 1, 0.5f); GL11.glBegin(GL11.GL_QUADS); // Start Drawing Quads // Front Face GL11.glNormal3f(0.0f, 0.0f, 1.0f); // Normal Pointing Towards Viewer GL11.glTexCoord2f(0.0f, 0.0f); GL11.glVertex3f(-1.0f, -1.0f, 1.0f); // Point 1 (Front) GL11.glTexCoord2f(1.0f, 0.0f); GL11.glVertex3f(1.0f, -1.0f, 1.0f); // Point 2 (Front) GL11.glTexCoord2f(1.0f, 1.0f); GL11.glVertex3f(1.0f, 1.0f, 1.0f); // Point 3 (Front) GL11.glTexCoord2f(0.0f, 1.0f); GL11.glVertex3f(-1.0f, 1.0f, 1.0f); // Point 4 (Front) glEnd();

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  • Checking for collisions on a 3D heightmap

    - by Piku
    I have a 3D heightmap drawn using OpenGL (which isn't important). It's represented by a 2D array of height data. To draw this I go through the array using each point as a vertex. Three vertices are wound together to form a triangle, two triangles to make a quad. To stop the whole mesh being tiny I scale this by a certain amount called 'gridsize'. This produces a fairly nice and lumpy, angular terrain kind of similar to something you'd see in old Atari/Amiga or DOS '3D' games (think Virus/Zarch on the Atari ST). I'm now trying to work out how to do collision with the terrain, testing to see if the player is about to collide with a piece of scenery sticking upwards or fall into a hole. At the moment I am simply dividing the player's co-ordinates by the gridsize to find which vertex the player is on top of and it works well when the player is exactly over the corner of a triangle piece of terrain. However... How can I make it more accurate for the bits between the vertices? I get confused since they don't exist in my heightmap data, they're a product of the GPU trying to draw a triangle between three points. I can calculate the height of the point closest to the player, but not the space between them. I.e if the player is hovering over the centre of one of these 'quads', rather than over the corner vertex of one, how do I work out the height of the terrain below them? Later on I may want the player to slide down the slopes in the terrain.

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  • How do I keep a 3D model on the screen in OpenGL?

    - by NoobScratcher
    I'm trying to keep a 3D model on the screen by placing my glDrawElement functions inside the draw function with the declarations at the top of .cpp. When I render the model, the model attaches it self to the current vertex buffer object. This is because my whole graphical user interface is in 2D quads except the window frame. Is there a way to avoid this from happening? or any common causes of this? Creating the file object: int index = IndexAssigner(1, 1); //make a fileobject and store list and the index of that list in a c string ifstream file (list[index].c_str() ); //Make another string //string line; points.push_back(Point()); Point p; int face[4]; Model rendering code: int numfloats = 4; float* point=reinterpret_cast<float*>(&points[0]); int num_bytes=numfloats*sizeof(float); cout << "Size Of Point" << sizeof(Point) << endl; GLuint vertexbuffer; glGenVertexArrays(1, &vao[3]); glGenBuffers(1, &vertexbuffer); glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer); glBufferData(GL_ARRAY_BUFFER, points.size()*sizeof(points), points.data(), GL_STATIC_DRAW); glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, num_bytes, &points[0]); glEnableClientState(GL_VERTEX_ARRAY); glVertexPointer(3, GL_FLOAT, points.size(), &points[0]); glEnableClientState(GL_INDEX_ARRAY); glIndexPointer(GL_FLOAT, faces.size(), faces.data()); glEnableVertexAttribArray(0); glDrawElements(GL_QUADS, points.size(), GL_UNSIGNED_INT, points.data()); glDrawElements(GL_QUADS, faces.size(), GL_UNSIGNED_INT, faces.data());

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  • How can I create an orthographic display that handles different screen dimensions?

    - by Piku
    I'm trying to create an iPad/iPhone game using GLES2.0 that contains a 3D scene with a heads-up-display/GUI overlaid on the top. However, this problem would also apply if I were to port my game to a computer and run the game in a resizable window, or allow the user to change screen resolutions... When trying to make the 2D GUI/HUD work I've made the assumption that all I'm really doing is drawing a load of 2D textured 'quads' on the screen and am trying to treat the orthographic projection as an old-style 2D display with 0,0 in the upper left and screenWidth,ScreenHeight in the lower right. This causes me all sorts of confusion when I rotate my ipad into Landscape mode since I can't work out what to put into my projection and modelview matrices to turn everything around the right way. It also gets messy if I want to support the iPad's large screen, an iPhone or a Retina display since I have to then draw three sets of textures for everything and work out which ones to use. Should I be trying to map the 2D OpenGL co-ords 1:1 with the screen? While typing out this question it occurs to me that I could keep my origin in the centre, still running -1/+1 along the axes. This would let me scale my 2D content appropriately on the different screen sizes, but wouldn't I end up with the textures being scaled and possibly losing quality? I'm using OpenGLES 2.0 and have a matrix library that has equivalents to the GLES1.1 glOrthof() and glFrustrum() calls.

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  • cheapest way to draw a fullscreen quad

    - by Soubok
    I wondering if there is a faster way to draw a full-screen quad in OpenGL: NewList(); PushMatrix(); LoadIdentity(); MatrixMode(PROJECTION); PushMatrix(); LoadIdentity(); Begin(QUADS); Vertex(-1,-1,0); Vertex(1,-1,0); Vertex(1,1,0); Vertex(-1,1,0); End(); PopMatrix(); MatrixMode(MODELVIEW); PopMatrix(); EndList();

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  • How to get a flat, non-interpolated color when using vertex shaders.

    - by Brett
    Hi, Is there a way to achieve this? If I draw lines like this glShadeModel(GL_FLAT); glBegin(GL_LINES); glColor3f(1.0, 1.0, 0.0); glVertex3fv(bottomLeft); glVertex3fv(topRight); glColor3f(1.0, 0.0, 0.0); glVertex3fv(topRight); glVertex3fv(topLeft); . . (draw a square) . . glEnd(); I get the desired result (a different colour for each edge) but I want to be able to calculate the fragment values in a shader. If I do the same after setting up my shader program I always get interpolated colors between vertices. Is there a way around this? (would be even better if I could get the same results using quads) Thanks

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  • OpenGL: Textured Primitives + High Framerate

    - by James D
    Short version: What's the best practice going forward for efficiently rendering large numbers of independent texture-mapped, lighted 2D/3D primitives (circles, rects, etc.) in OpenGL? For example: a typical particle system using billboarded quads/triangles, point sprites, or whatever other technique, with blending. Because after reading this thread on the messiness of OpenGL versioning/deprecation I'm starting to have my doubts. My specific question is not the ABCs of displaying primitives in OpenGL, but rather how to do so efficiently in post-deprecation (or pre-deprecation) OpenGL, in a way that's going to be compatible with a wide range of commodity hardware and in a way that's not going to break or itself get deprecated, five years down the line. Thanks!

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  • Fastest way of converting a quad to a triangle strip?

    - by Tina Brooks
    What is the fastest way of converting a quadrilateral (made up of foyr x,y points) to a triangle strip? I'm well aware of the general triangulation algorithms that exist, but I need a short, well optimized algorithm that deals with quadrilaterals only. My current algorithm does this, which works for most quads but still gets the points mixed up for some: #define fp(f) bounds.p##f /* Sort four points in ascending order by their Y values */ point_sort4_y(&fp(1), &fp(2), &fp(3), &fp(4)); /* Bottom two */ if (fminf(-fp(1).x, -fp(2).x) == -fp(2).x) { out_quad.p1 = fp(2); out_quad.p2 = fp(1); } else { out_quad.p1 = fp(1); out_quad.p2 = fp(2); } /* Top two */ if (fminf(-fp(3).x, -fp(4).x) == -fp(3).x) { out_quad.p3 = fp(3); out_quad.p4 = fp(4); } else { out_quad.p3 = fp(4); out_quad.p4 = fp(3); }

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  • 3d / 2.5d game library for iphone and pc

    - by Aaron Qian
    I'm trying to make a 2d shooter game with 3d background. The player and enemies are essentially just quads with textures. The background will be simple 3d polygons with textures and some fog and light. Therefore, I don't need a really powerful 3d library. I tried Unity3D and Torque2D, but I don't like to use their GUI editors. I prefer to work with code. So, is there a cross platform (mainly windows and iPhone) 3d / 2.5d game library, commercial or open source? I assume it will be only limited to c, c++, and object-c due to apple's new ToS.

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  • How to stop rendering invisible faces

    - by TheMorfeus
    I am making a voxel-based game, and for needs of it, i am creating a block rendering engine. Point is, that i need to generate lots of cubes. Every time i render more than 16x16x16 chunk of theese blocks, my FPS is dropped down hardly, because it renders all 6 faces of all of theese cubes. THat's 24 576 quads, and i dont want that. So, my question is, How to stop rendering vertices(or quads) that are not visible, and therefore increase performance of my game? Here is class for rendering of a block: public void renderBlock(int posx, int posy, int posz) { try{ //t.bind(); glEnable(GL_CULL_FACE); glCullFace(GL_BACK);// or even GL_FRONT_AND_BACK */); glPushMatrix(); GL11.glTranslatef((2*posx+0.5f),(2*posy+0.5f),(2*posz+0.5f)); // Move Right 1.5 Units And Into The Screen 6.0 GL11.glRotatef(rquad,1.0f,1.0f,1.0f); glBegin(GL_QUADS); // Draw A Quad GL11.glColor3f(0.5f, 0.4f, 0.4f); // Set The Color To Green GL11.glTexCoord2f(0,0); GL11.glVertex3f( 1f, 1f,-1f); // Top Right Of The Quad (Top) GL11.glTexCoord2f(1,0); GL11.glVertex3f(-1f, 1f,-1f); // Top Left Of The Quad (Top) GL11.glTexCoord2f(1,1); GL11.glVertex3f(-1f, 1f, 1f); // Bottom Left Of The Quad (Top) GL11.glTexCoord2f(0,1); GL11.glVertex3f( 1f, 1f, 1f); // Bottom Right Of The Quad (Top) //GL11.glColor3f(1.2f,0.5f,0.9f); // Set The Color To Orange GL11.glTexCoord2f(0,0); GL11.glVertex3f( 1f,-1f, 1f); // Top Right Of The Quad (Bottom) GL11.glTexCoord2f(0,1); GL11.glVertex3f(-1f,-1f, 1f); // Top Left Of The Quad (Bottom) GL11.glTexCoord2f(1,1); GL11.glVertex3f(-1f,-1f,-1f); // Bottom Left Of The Quad (Bottom) GL11.glTexCoord2f(1,0); GL11.glVertex3f( 1f,-1f,-1f); // Bottom Right Of The Quad (Bottom) //GL11.glColor3f(1.0f,0.0f,0.0f); // Set The Color To Red GL11.glTexCoord2f(0,0); GL11.glVertex3f( 1f, 1f, 1f); // Top Right Of The Quad (Front) GL11.glTexCoord2f(1,0); GL11.glVertex3f(-1f, 1f, 1f); // Top Left Of The Quad (Front) GL11.glTexCoord2f(1,1); GL11.glVertex3f(-1f,-1f, 1f); // Bottom Left Of The Quad (Front) GL11.glTexCoord2f(0,1); GL11.glVertex3f( 1f,-1f, 1f); // Bottom Right Of The Quad (Front) //GL11.glColor3f(1f,0.5f,0.0f); // Set The Color To Yellow GL11.glTexCoord2f(0,0); GL11.glVertex3f( 1f,-1f,-1f); // Bottom Left Of The Quad (Back) GL11.glTexCoord2f(1,0); GL11.glVertex3f(-1f,-1f,-1f); // Bottom Right Of The Quad (Back) GL11.glTexCoord2f(1,1); GL11.glVertex3f(-1f, 1f,-1f); // Top Right Of The Quad (Back) GL11.glTexCoord2f(0,1); GL11.glVertex3f( 1f, 1f,-1f); // Top Left Of The Quad (Back) //GL11.glColor3f(0.0f,0.0f,0.3f); // Set The Color To Blue GL11.glTexCoord2f(0,1); GL11.glVertex3f(-1f, 1f, 1f); // Top Right Of The Quad (Left) GL11.glTexCoord2f(1,1); GL11.glVertex3f(-1f, 1f,-1f); // Top Left Of The Quad (Left) GL11.glTexCoord2f(1,0); GL11.glVertex3f(-1f,-1f,-1f); // Bottom Left Of The Quad (Left) GL11.glTexCoord2f(0,0); GL11.glVertex3f(-1f,-1f, 1f); // Bottom Right Of The Quad (Left) //GL11.glColor3f(0.5f,0.0f,0.5f); // Set The Color To Violet GL11.glTexCoord2f(0,0); GL11.glVertex3f( 1f, 1f,-1f); // Top Right Of The Quad (Right) GL11.glTexCoord2f(1,0); GL11.glVertex3f( 1f, 1f, 1f); // Top Left Of The Quad (Right) GL11.glTexCoord2f(1,1); GL11.glVertex3f( 1f,-1f, 1f); // Bottom Left Of The Quad (Right) GL11.glTexCoord2f(0,1); GL11.glVertex3f( 1f,-1f,-1f); // Bottom Right Of The Quad (Right) //rquad+=0.0001f; glEnd(); glPopMatrix(); }catch(NullPointerException t){t.printStackTrace(); System.out.println("rendering block failed");} } Here is code that renders them: private void render() { GL11.glClear(GL11.GL_COLOR_BUFFER_BIT|GL11.GL_DEPTH_BUFFER_BIT); for(int y=0; y<32; y++){ for(int x=0; x<16; x++){ for(int z=0; z<16; z++) { b.renderBlock(x, y, z); } } } }

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  • Voxel Face Crawling (Mesh simplification, possibly using greedy)

    - by Tim Winter
    This is in regards to a Minecraft-like terrain engine. I store blocks in chunks (16x256x16 blocks in a chunk). When I generate a chunk, I use multiple procedural techniques to set the terrain and to place objects. While generating, I keep one 1D array for the full chunk (solid or not) and a separate 1D array of solid blocks. After generation, I iterate through the solid blocks checking their neighbors so I only generate block faces that don't have solid neighbors. I store which faces to generate in their own list (that's 6 lists, one per possible face). When rendering a chunk, I render all lists in the camera's current chunk and only the lists facing the camera in all other chunks. Using a 2D atlas with this little shader trick Andrew Russell suggested, I want to merge similar faces together completely. That is, if they are in the same list (same normal), are adjacent to each other, have the same light level, etc. My assumption would be to have each of the 6 lists sorted by the axis they rest on, then by the other two axes (the list for the top of a block would be sorted by it's Y value, then X, then Z). With this alone, I could quite easily merge strips of faces, but I'm looking to merge more than just strips together when possible. I've read up on this greedy meshing algorithm, but I am having a lot of trouble understanding it. To even use it, I would think I'd need to perform a type of flood-fill per sorted list to get the groups of merge-able faces. Then, per group, perform the greedy algorithm. It all sounds awfully expensive if I would ever want dynamic terrain/lighting after initial generation. So, my question: To perform merging of faces as described (ignoring whether it's a bad idea for dynamic terrain/lighting), is there perhaps an algorithm that is simpler to implement? I would also quite happily accept an answer that walks me through the greedy algorithm in a much simpler way (a link or explanation). I don't mind a slight performance decrease if it's easier to implement or even if it's only a little better than just doing strips. I worry that most algorithms focus on triangles rather than quads and using a 2D atlas the way I am, I don't know that I could implement something triangle based with my current skills. PS: I already frustum cull per chunk and as described, I also cull faces between solid blocks. I don't occlusion cull yet and may never.

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  • Textures do not render on ATI graphics cards?

    - by Mathias Lykkegaard Lorenzen
    I'm rendering textured quads to an orthographic view in XNA through hardware instancing. On Nvidia graphics cards, this all works, tested on 3 machines. On ATI cards, it doesn't work at all, tested on 2 machines. How come? Culling perhaps? My orthographic view is set up like this: Matrix projection = Matrix.CreateOrthographicOffCenter(0, graphicsDevice.Viewport.Width, -graphicsDevice.Viewport.Height, 0, 0, 1); And my elements are rendered with the Z-coordinate 0. Edit: I just figured out something weird. If I do not call this spritebatch code above doing my textured quad rendering code, then it won't work on Nvidia cards either. Could that be due to culling information or something like that? Batch.Instance.SpriteBatch.Begin(SpriteSortMode.Immediate, BlendState.AlphaBlend, SamplerState.LinearClamp, DepthStencilState.Default, RasterizerState.CullNone); ... spriteBatch.End(); Edit 2: Here's the full code for my instancing call. public void DrawTextures() { Batch.Instance.SpriteBatch.Begin(SpriteSortMode.Texture, BlendState.AlphaBlend, SamplerState.LinearClamp, DepthStencilState.Default, RasterizerState.CullNone, textureEffect); while (texturesToDraw.Count > 0) { TextureJob texture = texturesToDraw.Dequeue(); spriteBatch.Draw(texture.Texture, texture.DestinationRectangle, texture.TintingColor); } spriteBatch.End(); #if !NOTEXTUREINSTANCING // no work to do if (positionInBufferTextured > 0) { device.BlendState = BlendState.Opaque; textureEffect.CurrentTechnique = textureEffect.Techniques["Technique1"]; textureEffect.Parameters["Texture"].SetValue(darkTexture); textureEffect.CurrentTechnique.Passes[0].Apply(); if ((textureInstanceBuffer == null) || (positionInBufferTextured > textureInstanceBuffer.VertexCount)) { if (textureInstanceBuffer != null) textureInstanceBuffer.Dispose(); textureInstanceBuffer = new DynamicVertexBuffer(device, texturedInstanceVertexDeclaration, positionInBufferTextured, BufferUsage.WriteOnly); } if (positionInBufferTextured > 0) { textureInstanceBuffer.SetData(texturedInstances, 0, positionInBufferTextured, SetDataOptions.Discard); } device.Indices = textureIndexBuffer; device.SetVertexBuffers(textureGeometryBuffer, new VertexBufferBinding(textureInstanceBuffer, 0, 1)); device.DrawInstancedPrimitives(PrimitiveType.TriangleStrip, 0, 0, textureGeometryBuffer.VertexCount, 0, 2, positionInBufferTextured); // now that we've drawn, it's ok to reset positionInBuffer back to zero, // and write over any vertices that may have been set previously. positionInBufferTextured = 0; } #endif }

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  • Height Map Mapping to "Chunked" Quadrilateralized Spherical Cube

    - by user3684950
    I have been working on a procedural spherical terrain generator for a few months which has a quadtree LOD system. The system splits the six faces of a quadrilateralized spherical cube into smaller "quads" or "patches" as the player approaches those faces. What I can't figure out is how to generate height maps for these patches. To generate the heights I am using a 3D ridged multi fractals algorithm. For now I can only displace the vertices of the patches directly using the output from the ridged multi fractals. I don't understand how I generate height maps that allow the vertices of a terrain patch to be mapped to pixels in the height map. The only thing I can think of is taking each vertex in a patch, plug that into the RMF and take that position and translate into u,v coordinates then determine the pixel position directly from the u,v coordinates and determine the grayscale color based on the height. I feel as if this is the right approach but there are a few other things that may further complicate my problem. First of all I intend to use "height maps" with a pixel resolution of 192x192 while the vertex "resolution" of each terrain patch is only 16x16 - meaning that I don't have any vertices to sample for the RMF for most of the pixels. The main reason the height map resolution is higher so that I can use it to generate a normal map (otherwise the height maps serve little purpose as I can just directly displace vertices as I currently am). I am pretty much following this paper very closely. This is, essentially, the part I am having trouble with. Using the cube-to-sphere mapping and the ridged multifractal algorithm previously described, a normalized height value ([0, 1]) is calculated. Using this height value, the terrain position is calculated and stored in the first three channels of the positionmap (RGB) – this will be used to calculate the normalmap. The fourth channel (A) is used to store the height value itself, to be used in the heightmap. The steps in the first sentence are my primary problem. I don't understand how the pixel positions correspond to positions on the sphere and what positions are sampled for the RMF to generate the pixels if only vertices cannot be used.

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