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• OpenGL ES 1 Pixel Error?

  - by Beginner001

  I am developing a game on android using OpenGL ES 1.0 for Android OS. It is a 2d game using a simple Orthographic projection and textures for the sprites. One of these textures has a small line (it looks like 1 pixel) all the way across the top that has the same colors as the bottom 1-pixel line of the texture. It is almost as if the bottom line of the image raster was copied and pasted as the top line as well. Is anyone familiar with this type of error? What could the problem be?

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• Bad FPS for smaller size (OpenGL ES with SDL)

  - by ber4444

  If you saw my other question, well, there is still a little problem: Click here to watch on youtube Basically, the frame rate is very bad on the actual device, where for some reason the animation is scaled (it looks like the left side on the video). It is quite fast on the simulator where it is not scaled (right side). For a test, I submitted this new changeset that hard-codes the smaller size (plus increases the point size for HII regions to make the dust clouds more visible), and as you see in the video, now it is slow even in the simulator (left side shows the small size, right side shows the original size -- otherwise the code is the same). I'm clueless why it's soooo slow with a smaller galaxy, in fact it should be FASTER. As for general speed optimization (which is not strictly part of my question but is closely related to it, esp. if we need a workaround to speed things up), some initial ideas: reducing the number of items drawn may affect the appearance negatively but screen resolution could be reduced there are too many glBegin(GL_POINTS)/glEnd() blocks, we could draw more than just a single star at once

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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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• cocos2d/OpenGL multitexturing problem

  - by Gajoo

  I've got a simple shader to test multitextureing the problem is both samplers are using same image as their reference. the shader code is basically just this : vec4 mid = texture2D(u_texture,v_texCoord); float g = texture2D(u_guide,v_guideCoord); gl_FragColor = vec4(g , mid.g,0,1); and this is how I'm calling draw function : int last_State; glGetIntegerv(GL_ACTIVE_TEXTURE, &last_State); glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, getTexture()->getName()); glActiveTexture(GL_TEXTURE1); glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D, mGuideTexture->getName()); ccGLEnableVertexAttribs( kCCVertexAttribFlag_TexCoords |kCCVertexAttribFlag_Position); glVertexAttribPointer(kCCVertexAttrib_Position, 2, GL_FLOAT, GL_FALSE, 0, vertices); glVertexAttribPointer(kCCVertexAttrib_TexCoords, 2, GL_FLOAT, GL_FALSE, 0, texCoord); glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); glDisable(GL_TEXTURE_2D); I've already check mGuideTexture->getName() and getTexture()->getName() are returning correct textures. but looking at the result I can tell, both samplers are reading from getTexture()->getName(). here are some screen shots showing what is happening : The image rendered Using above codes The image rendered when I change textures passed to samples I'm expecting to see green objects from the first picture with red objects hanging from the top.

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• Replace these OpenGL functions with OpenGL ES?

  - by Constantin

  I search for a possibility to migrate my PC OpenGL application and an iPhone App into one XCode project (for convenience). So if I make chances to these source files I want to apply this for both plattforms and want to be able to compile for both plattforms from one project. How could I accomplish this? Is there a way to do so in XCode 4 or 3.25? Any help would be highly appreciated edit: Okay, I went so far - All in all, it seems to work with XCode 4. My only problems are these openGL/Glut functions, that aren't working on iPhone: glPushAttrib( GL_DEPTH_BUFFER_BIT | GL_LIGHTING_BIT ); glPopAttrib(); glutGet(GLUT_ELAPSED_TIME); glutSwapBuffers(); Any ideas how to fix these issues?

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• Creating an OpenGL FPS camera: I have the position and orientation vectors, now what?

  - by Synthetix

  I have been struggling to create a first person camera in OpenGL ES 2.0 without using gluLookAt(). I grab the camera's orientation vectors (the way it's looking) from the current modelview matrix, and use that to calculate the new forward/backward (Z) translation value. I then calculate the strafe (X) value from the dot product of Z and Y (which is always 1.0). So, I have all the information I need to create a view matrix, but how do I do that without using gluLookAt? Almost all the examples I've seen use gluLookAt, but no such function exists in OpenGL ES 2.0. Besides, one of the moderators on cprogramming.com mentioned that gluLookAt is not appropriate for FPS cameras: http://cboard.cprogramming.com/game-programming/135390-how-properly-move-strafe-yaw-pitch-camera-opengl-glut-using-glulookat.html I am really confused by all the conflicting information I'm getting. I just want to create a first person camera that goes forward (W,S keys), side-to-side (A,D keys) and rotates around its center (Y axis only), Wolfenstein style. Any help on this would be much appreciated!

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• OpenGL|ES on a desktop PC.

  - by almb

  I'm working on a OpenGL project that I would like to port to embedded systems that support OpenGL|ES. Since OpenGL|ES is a subset of OpenGL how hard would it be to compile my OpenGL application on an embedded system? (Assuming that my OpenGL code is in the limits of OpenGL|ES) I guess what I'm wondering is: is it possible to dircetly wrap my OpenGL calls with MACROS to make it compatible with OpenGL|ES API call names? Are there any calls specific to OpenGL|ES that I would have to implement? Sorry, if I'm not clear. Thank you.

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• OpenGL ES 2.0 texture distortion on large geometry

  - by Spruce

  OpenGL ES 2.0 has serious precision issues with texture sampling - I've seen topics with a similar problem, but I haven't seen a real solution to this "distorted OpenGL ES 2.0 texture" problem yet. This is not related to the texture's image format or OpenGL color buffers, it seems like it's a precision error. I don't know what specifically causes the precision to fail - it doesn't seem like it's just the size of geometry that causes this distortion, because simply scaling vertex position passed to the the vertex shader does not solve the issue. Here are some examples of the texture distortion: Distorted Texture (on OpenGL ES 2.0): http://i47.tinypic.com/3322h6d.png What the texture normally looks like (also on OpenGL ES 2.0): http://i49.tinypic.com/b4jc6c.png The texture issue is limited to small scale geometry on OpenGL ES 2.0, otherwise the texture sampling appears normal, but the grainy effect gradually worsens the further the vertex data is from the origin of XYZ(0,0,0) These texture issues do not occur on desktop OpenGL (works fine under Windows XP, Windows 7, and Mac OS X) I've only seen the problem occur on Android, iPhone, or WebGL(which is similar to OpenGL ES 2.0) All textures are power of 2 but the problem still occurs Scaling the vertex data - The values of a vertex's X Y Z location are in the range of: -65536 to +65536 floating point I realized this was large, so I tried dividing the vertex positions by 1024 to shrink the geometry and hopefully get more accurate floating point precision, but this didn't fix or lessen the texture distortion issue Scaling the modelview or scaling the projection matrix does not help Changing texture filtering options does not help Disabling mipmapping, or using GL_NEAREST/GL_LINEAR does nothing Enabling/disabling anisotropic does nothing The banding effect still occurs even when using GL_CLAMP Dividing the texture coords passed to the vertex shader and then multiplying them back to the correct values in the fragment shader, also does not work precision highp sampler2D, highp float, highp int - in the fragment or the vertex shader didn't change anything (lowp/mediump did not work either) I'm thinking this problem has to have been solved at one point - Seeing that OpenGL ES 2.0 -based games have been able to render large-scale, highly detailed geometry

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• Starting out with OpenGL when most tutorials are out of date

  - by AUTO

  I'm sure there are already a bunch of questions like this asked, but the constant updating of the OpenGL library throws them all away, and in a month or two, the answers here will be worthless again. I am ready to start programming in OpenGL using C++. I've got a working compiler (DevCpp; do NOT ask me to switch to VC++, and don't ask me why). Now I'm just looking for a solid tutorial on how to program with OpenGL. My assistant found the tutorial provided by NeHe Productions, but as I've come to find out, it's WAY OUT OF DATE! (although I did pull together a basic window to support an OpenGL canvas) Then I went online, and found the OpenGL SuperBible, which apparently uses freeglut? But what I'd like to know is whether or not SuperBible 5th edition is up to date any longer. The suggestion to freeglut I found said the latest version was 2.6.0 but now it's 2.8.0! Is the OpenGL SuperBible still a good, and fairly up-to-date place to start? Is there a better place to go to learn OpenGL? Am I allowed to simply store freeglut in the DevCpp include directory (maybe in GL), or is there some important procedure? Are there any comments or suggestions that I didn't think to ask since I'm only just beginning? @dreta cleared some things up for me, so now I have a better idea of what to ask: I think I'd like to start out with OpenGL using a wrapper library instead of directly accessing OpenGL.I just think that, for a beginner, it would be easier for me to program and get good results, while I don't yet have to understand all the grimy details (as @stephelton mentioned). The problem is, I can't find any library that doesn't have undefined references to no longer supported functions. Freeglut sounds operational, but it still uses GLU.Does anyone know what I can do?Also, I tried compiling the first SuperBible's source, but I got errors since GLAPI is not being defined as a type, the error originating in the GLU library. I'd like to use the SuperBible, but I don't know how to fix this.

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• What is causing these visual artifacts on my OpenGL sprites?

  - by Amplify91

  What could be the cause of the defects in my characters sprite? I am using OpenGL ES 2.0. I draw my sprites in a sprite batch that uses UV coordinates from one large texture atlas. If you look around the character' edges, you'll see two noticeable problems: The invisible alpha background is not invisible, but shows a strange static-like background. There are unwanted streaks where the character nears the edge of the frame (but only in some frames of the animation, this happened to be one of them). Any idea what could be causing these? I will provide related code if asked for, but I'll try to avoid just dumping the entire project and expecting someone to look through it all. EDIT: Here's a bit of code: This is how I generate my UV coordinates: private float[] createFrameUV(int frameWidth, int frameHeight, int x, int y){ float[] uv = new float[4]; if(numberOfFrames>1){ float width = (float)frameWidth / (float)mBitmap.getWidth(); float height = (float)frameHeight / (float)mBitmap.getHeight(); float u = (float)x / (float)mBitmap.getWidth(); float v = (float)y / (float)mBitmap.getHeight(); uv[0] = u; uv[1] = v; uv[2] = u + width; uv[3] = v + height; }else{ uv[0] = 0f; uv[1] = 0f; uv[2] = 1f; uv[3] = 1f; } return uv; } These are some OpenGL settings: GLES20.glTexParameterf(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR); GLES20.glTexParameterf(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR); GLES20.glTexParameterf(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE); GLES20.glTexParameterf(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE);

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• Learning OpenGL ES 1.x

  - by Kristopher Johnson

  What is the quickest way to come up to speed on OpenGL ES 1.x? Let's assume I know nothing about OpenGL (which is not entirely true, but it's been a while since I last used OpenGL). I am most interested in learning this for iPhone-related development, but I'm interested in learning how it works on other platforms as well. I've found the book OpenGL ES 2.0 Programming Guide, but I am concerned that it might not be the best approach because it focuses on 2.0 rather than 1.x. My understanding is that 2.0 is not backwards-compatible with 1.x, so I may miss out on some important concepts. Note: For answers about learning general OpenGL, see http://stackoverflow.com/questions/62540/learning-opengl Some resources I've found: http://khronos.org/opengles/1_X/ http://www.imgtec.com/powervr/insider/sdk/KhronosOpenGLES1xMBX.asp OpenGL Distilled by Paul Martz (a good refresher on OpenGL basics)

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• Software emulated OpenGL with higher version than my graphics card supports

  - by leemes

  I have an Intel GMA 950 chipset in my netbook. I want to learn how to write OpenGL shader programs with this fantastic tutorial and therefore need OpenGL 3.3. Sadly, my graphics card only supports OpenGL 1.4. I think that MESA can emulate OpenGL in software, so I'm wondering if it can emulate OpenGL 3.3 without any hardware accelleration (performance is very much no problem, since this is only for learning and testing puroses). Is there any possibility to do this?

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• what packages should I install in ubuntu 12.04 to fulfill opengl requirements for using nouveau driver?

  - by karolszk

  I try to switch from nvidia to nouveau driver via script: !/bin/bash stop gdm rmmod nvidia sed -i "s/nouveau/nvidia/" /etc/modprobe.d/blacklist-nvidia-nouveau.conf update-alternatives --set gl_conf /usr/lib/mesa/ld.so.conf ldconfig modprobe nouveau cp /etc/X11/xorg.conf{.nouveau,} start gdm and driver is loaded and X started but compiz it doesn't. In .xsession-errors I see: Compiz (opengl) - Fatal: Root visual is not a GL visual compiz (opengl) - Error: initScreen failed compiz (core) - Error: Couldn't activate plugin 'opengl' Compiz (opengl) - Fatal: Root visual is not a GL visual Compiz (opengl) - Fatal: Root visual is not a GL visual Compiz (opengl) - Fatal: Root visual is not a GL visual Compiz (opengl) - Fatal: Root visual is not a GL visual Compiz (opengl) - Fatal: Root visual is not a GL visual Compiz (opengl) - Fatal: Root visual is not a GL visual Compiz (opengl) - Fatal: Root visual is not a GL visual Compiz (opengl) - Fatal: Root visual is not a GL visual gnome-session[19075]: WARNING: App 'compiz.desktop' respawning too quickly gnome-session[19075]: WARNING: Application 'compiz.desktop' killed by signal gnome-session[19075]: WARNING: App 'compiz.desktop' respawning too quickly what I'm doing wrong??

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• OpenGL: Attempt to allocate a texture to big for the current hardware

  - by AnonymousMan

  I'm getting the following error: java.io.IOException: Attempt to allocate a texture to big for the current hardware at org.newdawn.slick.opengl.InternalTextureLoader.getTexture(InternalTextureLoader.java:320) at org.newdawn.slick.opengl.InternalTextureLoader.getTexture(InternalTextureLoader.java:254) at org.newdawn.slick.opengl.InternalTextureLoader.getTexture(InternalTextureLoader.java:200) at org.newdawn.slick.opengl.TextureLoader.getTexture(TextureLoader.java:64) at org.newdawn.slick.opengl.TextureLoader.getTexture(TextureLoader.java:24) The image I'm trying to use is 128x128. System.out.println(GL11.glGetInteger(GL11.GL_MAX_TEXTURE_SIZE)); I get: 32. 32??!! My graphics card is AMD Radeon HD 7970M with 2048 MB GDDR5 RAM, I can run all the latest games in 1080p and 60fps with no problem, and those textures sure as hell doesn't look like they are 32x32 pixels to me! How can I fix this? -- Edit: Here's the chaos code I use to init OpenGL: Display.setDisplayMode(new DisplayMode(500,500)); Display.create(); if (!GLContext.getCapabilities().OpenGL11) { throw new Exception("OpenGL 1.1 not supported."); } Display.setTitle("Game"); glMatrixMode(GL_PROJECTION); glLoadIdentity(); GLU.gluPerspective(45, 1, 0.1f, 5000); Mouse.setGrabbed(true); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glEnable(GL_TEXTURE_2D); glClearColor(0, 0, 0, 0); glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LEQUAL); glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glEnable(GL_BLEND); glEnable(GL_POINT_SMOOTH); glEnable(GL_LINE_SMOOTH); glEnable(GL_POLYGON_SMOOTH); glEnable(GL_POLYGON_OFFSET_FILL); glShadeModel(GL_SMOOTH); Display is a LWJGL thing, it makes the OpenGL context and the window. Anyway, I don't think there's anything in the init code that can help me but you never know...

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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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• What is UVIndex and how do I use it on OpenGL?

  - by Delta

  I am a noob in OpenGL ES 2.0 (for WebGL) and I'm trying to draw a simple model I've made with a 3D tool and exported to .fbx format. I've been able to draw some models that only have: A vertex buffer, a index buffer for the vertices, a normal buffer and a texture coordinate buffer, but this model now has a "UVIndex" and I'm not sure where am I supposed to put this UVIndex. My code looks like this: GL.bindBuffer(GL.ARRAY_BUFFER, this.Model.House.VertexBuffer); GL.vertexAttribPointer(this.Shader.TextureAndLighting.Attribute["vPosition"],3,GL.FLOAT, false, 0, 0); GL.bindBuffer(GL.ARRAY_BUFFER, this.Model.House.NormalBuffer); GL.vertexAttribPointer(this.Shader.TextureAndLighting.Attribute["vNormal"], 3, GL.FLOAT, false, 0, 0); GL.bindBuffer(GL.ARRAY_BUFFER, this.Model.House.TexCoordBuffer); GL.vertexAttribPointer(this.Shader.TextureAndLighting.Attribute["TexCoord"], 2, GL.FLOAT, false, 0, 0); GL.bindBuffer(GL.ELEMENT_ARRAY_BUFFER, this.Model.House.IndexBuffer); GL.bindTexture(GL.TEXTURE_2D, this.Texture.HTex1); GL.activeTexture(GL.TEXTURE0); GL.drawElements(GL.TRIANGLES, this.Model.House.IndexBuffer.Length, GL.UNSIGNED_SHORT, 0); But my model renders totally incorrect and I think it has to do with the fact that I am ignoring this "UVIndex" in the .fbx file, since I've never drawn any model that uses this UVIndex I really have no clue on what to do with it. This is the json file containing the model's data: http://pastebin.com/raw.php?i=G294TVmz

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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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• Is OpenGL 1.x deprecated?

  - by QuasarDonkey

  I'm familiar with OpenGL 1.x. I typically use SDL with OpenGL 1.4 on Linux, and I've never run into problems, even on my modern system. I've read on the OpenGL site about deprecation and compatibility contexts, but I'm still unclear as to whether it's safe to continue to use old versions of OpenGL, as opposed to using old features in newer versions. When functionality is marked deprecated ... future versions of OpenGL may remove it. Does deprecation simply imply that those functions can't be used alongside newer features? More specifically, are there any systems today (other than embedded) where OpenGL 1.x isn't available? The old-skool stuff like, glBegin, glEnd, glDrawPixels, etc. Note: I'm not a professional games developer, so you'll have to excuse my ignorance. I'm working on a mostly 2D game that I would like to keep multi-platform, supporting at least Linux, Mac, and Windows.

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• iPhone post-processing with a single FBO with Opengl ES 2.0?

  - by Jing

  I am trying to implement post-processing (blur, bloom, etc.) on the iPhone using OpenGL ES 2.0. I am running into some issues. When rendering during my second rendering step, I end up drawing a completely black quad to the screen instead of the scene (it appears that the texture data is missing) so I am wondering if the cause is using a single FBO. Is it incorrect to use a single FBO in the following fashion? For the first pass (regular scene rendering), I attach a texture as COLOR_ATTACHMENT_0 and render to a texture. glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texturebuffer, 0) For the second pass (post-processing), I attach the color renderbuffer to COLOR_ATTACHMENT_0 glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, colorRenderbuffer) Then use the texture from the first pass for rendering as a quad on the screen.

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• How does opengl-es 2 assemble primitives?

  - by stephelton

  Two things I'm quite confused about. 1) OpenGL ES 2.0 creates primitives before the vertex shader is invoked. Why, then, does it not automatically provide the vertex shader the position of the vertex? 2) OpenGL ES 2.0 supports glDrawElements(), but it does not support glEnableClientState() or GL_VERTEX_ARRAY, so how can this call possibly be used to construct primitives? NOTE: this is OpenGL ES 2.0, NOT normal OpenGL! Thanks!

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• converting 2D mouse coordinates to 3D space in OpenGL ES

  - by Jayesh

  I want to convert mouse's current X and Y coordinates into the 3D space I have drawn in the viewport. I need to do this on the OpenGL ES platform. I found following possible solutions implemented in OpenGL, but none fits what I am looking for. I found NeHe's tutorial on doing exactly this, but in traditional OpenGL way. It uses gluUnProject. http://nehe.gamedev.net/data/articles/article.asp?article=13 Although gluUnProject is not available in OpenGL ES, its implementation seems simple enough to port back. But before calling it, we need to call glReadPixels with GL_DEPTH_COMPONENT and that is not possible in OpenGL ES. (The reason I found in this thread: http://www.khronos.org/message_boards/viewtopic.php?f=4&t=771) What I want to do is similar to picking, except that I don't want to select the object but I want exact coordinates so that I can recognize particular portion of the object that is currently under mouse cursor. I went through the Picking tutorials in this answer. http://stackoverflow.com/posts/2211312/revisions But they need glRenderMode, which I believe is absent in OpenGL ES. If you know how to solve this problem in OpenGL ES, please let me know. Thanks.

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• Recommended Books for OpenGL [closed]

  - by TheBlueCat

  I'm fairly new to OpenGL and I'm have been researching any books that would be beneficial, I've had suggested to me (I've finished reading the OpenGL Book online): Real Time Rendering GPU Gems 3 OpenGL Super Bible Does anyone know any other books that they've found useful in the past, even if it covers higher level algorithms. Also, can anyone suggest an IDE/Text Editor for Linux? I'm using Komodo and it's super buggy, I just booted into Windows today and tried Visual Studio and loved it, is their anything similar for Linux? Although, the books I've been reading are saying to not use IDEs, partly because of the reliance you place onto them, per se. I use Eclipse a lot for my Java programming, can I use C and OpenGL with that? Lastly, do you think it would be more beneficial staying on Windows and programming in C/OpenGL on their, I do like Linux, but I found Visual Studio to be pretty good in some aspects?

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• OpenGL doesn't draw (3.3+) [on hold]

  - by Dhiego Magalhães

  Brief: I've been following this tutorial about OpenGL for 2 days, and I still can't have a triangle drawn, so I'm asking for help here. The tutorial is turned to OpenGL version 3.3 programing, using vertex arrays, buffers, etc. The libraries are: GLFW3 and GLEW, and I setted them by myself. The screen keeps black all the time. Full code: link here (It's just like a Hello World opengl program) Further Details: I get no errors at all. I downloaded a software to test my video card, and it supports OpenGL 4.1+ Standard OpenGL code for drawing (from earlier version) such as this one works normally. I'm using Microsoft Visual Studio 10.0 I presume all the OpenGL implementation was dune right: I added Additional Dependences to the linker as glew32.lib, opengl32.lib, glfw3.lib. The glew.dll was placed at SysWOW64 - because I'm running window 64bits, and glew is 32. Notes: I've been working hard to find out what this is, but I can't find. I would appreciate if anyone could test this code for me, so I can know if I implemented something wrong, and that its not my code.

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• Can I use PBOs for textures in iOS?

  - by Radu

  As far as I can see, there is no GL_PIXEL_UNPACK_BUFFER. Also, the OpenGL ES 2.0 specification (and as far as I know, no iOS device currently supports OpenGL ES 2.0) states that glMapBufferOES() can only use GL_ARRAY_BUFFER as a target, yet glTexImage2D() and glTexSubImage2D() only seem to use PBOs if GL_PIXEL_UNPACK_BUFFER is bound. The OpenGL documentation for glBindBuffer() also states that: GL_PIXEL_PACK_BUFFER and GL_PIXEL_UNPACK_BUFFER are available only if the GL version is 2.1 or greater. So, can I use PBOs for textures? Am I missing something obvious?

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• Convert OpenGL code to DirectX

  - by Fredrik Boston Westman

  First of all, this is kind of a follow up question on @byte56 excellent anwser on this question concerning picking algorithms. I'm trying to convert one of his code examples to directX 11 however I have run into some problems ( I can pick but the picking is way off), and I wanted to make sure I had done it right before moving on and checking the rest of my code. I am not that familiar with openGl but I can imagine openGl has different coordinations systems, and functions that alters how you must implement to code a bit. The getPickRay function on the answer linked is what I'm trying to convert. This is the part of my code that I think is giving me trouble when converting from openGl to directX Because I'm unsure on how their different coordination systems differs from one another. PRVecX = ((( 2.0f * mouseX) / ClientWidth ) - 1 ) * tan((viewAngle)/2); PRVecY = (1-(( 2.0f * mouseY) / ClientHeight)) * tan((viewAngle)/2); Another thing that I am unsure about is this part: XMVECTOR worldSpaceNear = XMVector3TransformCoord(cameraSpaceNear, invMat); XMVECTOR worldSpaceFar = XMVector3TransformCoord(cameraSpaceFar, invMat); A couple of notes: The mouse coordinates are already converted so that the top left corner of the client window would be (0,0) and the bottom right (800,600) ( or whatever resolution you would have) The viewAngle is the same angle that I used when setting the camera view with XMMatrixPerspectiveFovLH. I removed the variables aspectRatio and zoomFactor because I assumed that they were related to some specific function of his game. To summarize it up to questions : Does the openGL coordination system differ in such a way that this equation in the first of my code examples wouldn't be valid when used in DirectX 11 ( with its respective screen coordination system)? Is the openGL method Matrix4f.transform(a, b, c) equal to the directX method c = XMVector3TransformCoord(b,a)? (where a is a matrix and b,c are vectors). Because I know when it comes to matrices order is important.

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