opengl-es-2.0

问题 I had a bug that took me quite some time to fix. I kept getting EXC_BAD_ACCESS and a reference to a memmove error without any further description until I commented the following line: [self loadShaders]; glGenVertexArraysOES(1, &_vao); glBindVertexArrayOES(_vao); // Vertex Buffer glGenBuffers(1, &_vertexBuffer); glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer); glBufferData(GL_ARRAY_BUFFER, sizeof(Vertices), Vertices, GL_STATIC_DRAW); glEnableVertexAttribArray(ATTRIB_VERTEX);

问题 i am new to openGL. Iam using apple documentation as my major referens http://developer.apple.com/library/ios/#documentation/3DDrawing/Conceptual/OpenGLES_ProgrammingGuide/TechniquesforWorkingwithVertexData/TechniquesforWorkingwithVertexData.html#//apple_ref/doc/uid/TP40008793-CH107-SW6 My problem is that i am using openGL ES 1.1 and not 2 thus functions which are used in Listing 9-3 such as glVertexAttribPointer , glEnableVertexAttribArray are not recognized ... :) I trying to make the

问题 When trying to press the back button quickly during launching some Activities with GLSurfaceView , eglCreateWindowSurface fails with java.lang.IllegalArgumentException . I got the following errors: 10-08 18:05:36.490: E/GLSurfaceView(3440): eglCreateWindowSurface 10-08 18:05:36.490: E/GLSurfaceView(3440): java.lang.IllegalArgumentException: Make sure the SurfaceView or associated SurfaceHolder has a valid Surface 10-08 18:05:36.490: E/GLSurfaceView(3440): at com.google.android.gles_jni

问题 I need gl_FragColor to "paint" floating point values, which also can be negative (x < 0) and > 1.0. I then want to use the color attachement of the FBO this values where rendered to and use it as a texture in another FBO. Now I have read on http://www.khronos.org/opengles/sdk/docs/man/ (under glTexImage2D) that all values are clamped to a range of [0, 1] and also I didn't find a glClampColor instruction. Is there a possibility to find a workaround here or does somebody have an idea which

问题 I've seen the occasional article suggest ordering your vertices from nearest to furthest from the camera when sending them to OpenGL (for any of the OpenGL variants). The reason suggested by this is that OpenGL will not fully process/render a vertex if it is behind another vertex already rendered. Since ordering vertices by depth is a costly component of any project, as typically this ordering frequently changes, how common or necessary is such design? I had previously thought that OpenGL

问题 I'm trying to port Apples GLPaint example to use GLKit. Using a UIView, its possible to return the CAEAGLLayer of the view and set the drawableProperties to include kEAGLDrawablePropertyRetainedBacking. This has the effect of retaining the drawable contents after presenting the render buffer, as expected. Removing this property results in flickering after the draw call with part of the drawable content seemingly being drawn to different buffers. The problem is this is exactly the issue I am

问题 This question already has an answer here : Closed 7 years ago . Possible Duplicate: Drawing a sphere in OpenGL ES I have been browsing around for quite some time now, and have yet to find an adequate answer. I started learning Opengl es 2.0 (Because I need to for a project in university) and have recently accomplished drawing a circle. WOOPIE! I have looked at a great deal of similar questions, but it is either outdated or I too complex for me to grasp. Can anyone point me in the proper

问题 You know the sample code of Apple with the CameraRipple effect? Well I'm trying to record the camera output in a file after openGL has done all the cool effect of water. I've done it with glReadPixels, where I read all the pixels in a void * buffer , create CVPixelBufferRef and append it to the AVAssetWriterInputPixelBufferAdaptor, but it's too slow, coz readPixels takes tons of time. I found out that using FBO and texture cash you can do the same, but faster. Here is my code in drawInRect

问题 I know perspective division is done by dividing x,y, and z by w, to get normalized device coordinates. But I am not able to understand the purpose of doing that. Also, does it have anything to do with clipping? 回答1: I mean why do we need that? In layman terms: To make perspective distortion work. In a perspective projection matrix, the Z coordinate gets "mixed" into the W output component. So the smaller the value of the Z coordinate, i.e. the closer to the origin, the more things get scaled

问题 I have a Renderscript which processes an image that is given in output to an Allocation. I want to use this Allocation as a texture in my OpenGL program but I don't know how to get a texture ID from the Allocation. On the other hand, I know I could use a graphic Renderscript, but since it has been deprecated, I guess there must be some other way to achieve the same result. 回答1: Specify USAGE_IO_OUTPUT when you create the Allocation. Assuming you are generating the texture data in a script you