vertex-buffer

问题 For the other buffers there are functions like: glVertexArrayVertexAttribOffsetEXT( this->handle, // vao handle vbo.getHandle(), // vbo handle index, // specifies the index of the generic vertex attribute to be modified. size, // number of components per generic vertex attribute vbo.getType(), // specifies the data type of each component in the array normalized, // specifies whether fixed-point data values should be normalized stride, // specifies the byte offset between consecutive generic

问题 I was looking for ways to associate attributes with arbitrary groupings of verticies, at first instancing appeared to be the only way for me to accomplish this, but then I stumbled up this question and this answer states : However what is possible with newer versions of OpenGL is setting the rate at which a certain vertex attribute's buffer offset advances. Effectively this means that the data for a given vertex array gets duplicated to n vertices before the buffer offset for a attribute

问题 I am working on a 3d tile-based strategy game and have read that implementing VBO's will significantly increase the game's frame rate and reduce the cpu usage (sounds great right?). However, among the tutorials I've looked at I can't quite get a handle on how to implement it. Has anyone had experience doing this and can either point me to a reliable source or provide sample code that actually works? Thanks! 回答1: Are these suitable? http://www.songho.ca/opengl/gl_vbo.html http://www.opengl.org

问题 I have been working on an animated graphics project with very specific requirements, and after quite a bit of searching and test coding, I have figured that I could take several approaches, but the Khronos and MDN documentation I have been reading coupled with other posts I have seen here don't answer all of my questions regarding my particular project. In the meantime, I have written short test programs (setting infrastructure for testing). Firstly, I should describe the project: The main

问题 I am developing an iPhone game using OpenGL ES 1.1 and need to use vertex buffer objects in order to render 500+ particles without the performance decreasing. My game was able to draw successfully using the non-VBO method, but now that I've attempted to incorporate VBOs, nothing is drawing anymore. Please help me to identify what I am doing wrong and provide a correct example. I have a class called TexturedQuad which consists of the following: // TexturedQuad.h enum { ATTRIB_POSITION, ATTRIB

问题 I'm trying to draw a terrain with GL_TRIANGLE_STRIP and glDrawElements but I'm having a really hard time understanding the indices thing behind glDrawElements ... Here's what I have so far: void Terrain::GenerateVertexBufferObjects(float ox, float oy, float oz) { float startWidth, startLength, *vArray; int vCount, vIndex = -1; // width = length = 256 startWidth = (width / 2.0f) - width; startLength = (length / 2.0f) - length; vCount = 3 * width * length; vArray = new float[vCount]; for(int z

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 In my cross platform OpenGL application I want to draw using vertex buffer objects. However I run into problems invoking glDrawRangeElements. glDrawRangeElements(GL_TRIANGLES, start, start + count, count, GL_UNSIGNED_INT, static_cast<GLvoid *> (start * sizeof(unsigned int))); The compiler (CLang on Mac OS X) does not like the last argument "error: cannot cast from type 'unsigned long' to pointer type 'GLvoid *' (aka 'void *')". OpenGL API defines the type of last arguments as const GLvoid *

问题 In the stock OpenGL ES app you get (when you create a new "OpenGL game" in XCode), in the setupGL function, there is: glEnable(GL_DEPTH_TEST); //glGenVertexArraysOES( 1, &_vertexArray ) ; // va's are not being used! //glBindVertexArrayOES( _vertexArray ) ; // we comment these out // to no ill effect -- are these calls extraneous? glGenBuffers( 1, &_vertexBuffer ) ; glBindBuffer( GL_ARRAY_BUFFER, _vertexBuffer ) ; glBufferData( GL_ARRAY_BUFFER, sizeof(gCubeVertexData), gCubeVertexData, GL

问题 So I've been learning OpenGL 3.3 on https://open.gl/ and I got really confused about some stuff. VAO-s. By my understanding they are used to store the glVertexAttribPointer calls. VBO-s. They store vertecies. So if I am making something with multiple objects do I need a VBO for every object? Shader Programs - Why do we need multiple ones and what exactly do they do ? What exactly does this line do : glBindFragDataLocation(shaderProgram, 0, "outColor"); The most important thing is how does all