vertex-buffer

问题 Can someone offer a tutorial for using vertex buffer objects (VBOs) in Android? I am working on a 2D HUD which is drawn using OpenGL ES 2 on Android. 回答1: The best OpenGL ES tutorials are not specifically for Android, but the way VBOs are used will be directly portable. The best OpenGL ES examples are in the PowerVR SDK. There is also a collection of relevant articles on my blog that will help too. 回答2: Here's some: Most basic working vbo example http://www.opengl.org/wiki/VBO_-_just_examples

问题 I'm creating two different vertex buffers, that use two different shaders to render them . As soon as I bind the second vertex buffer, the data I parked in the first vertex buffer seems to be corrupted or lost. If I generate and draw one vertex buffer only, like so: glGenBuffers( 1, &vb1 ) ; glBindBuffer( GL_ARRAY_BUFFER, vb1 ) ; // fill it.. glBufferData( .. ) Then, in the draw() loop, glUseProgram( shader1 ) ; glBindBuffer( vb1 ) ; // make sure it is bound glDrawArrays( ... ) // draw it

问题 I'm following this guide and I'm trying to draw a quad to the screen. I also saw the source code, it's the same and it should work, but in my case nothing is displayed on the screen. I'm using OpenGL 2.0 with a vertex shader that just sets the color to be red in a way that the quad should be visible on the screen. Before callig glutMainLoop I generate the vertex buffer object: #include <GL/glut.h> #include <GL/glew.h> vector<GLfloat> quad; GLuint buffer; void init() { // This routine gets

问题 I have an OpenGL-related issue. Whenever I attempt to draw a simple polygon using four vertices from a vertex buffer... nothing happens. However, it will draw the shape in GL_TRIANGLES or GL_TRIANGLE_STRIP mode, albeit distorted. Am I doing something wrong? Relevent code: Vertex array: http://i.imgur.com/nEcbw.png GL_POLYGON: http://i.imgur.com/idfFT.png GL_TRIANGLES: http://imgur.com/84ey3,idfFT,nEcbw#0 GL_TRIANGLE_STRIP: http://i.imgur.com/JU3Zl.png 回答1: I'm using a forward-compatible 3.2

问题 I'm using the glDrawElements call with VBOs to render my scene. The scene is a cloth with vertices and texture coordinates - in this example, I'm rendering a flag. With my scene, the vertices are dynamic which means I need to write to a VBO every frame. Much of my processing is done on the GPU using CUDA, so I'm constantly mapping CPU memory to GPU memory. The texture coordinates, on the other hand, are static. In order to render with glDrawElements (as I understand it), I should interleave

问题 I'm trying to create 2 vertex buffers, one that only stores positions and another that only stores colors. This is just an exercise from Frank Luna's book to become familiar with vertex description, layouts and buffer options. The problem is that I feel like I have made all the relevant changes and although I am getting the geometry to show, the color buffer is not working. To complete the exercise, instead of using the book's Vertex vertices[]={{...},{...},...} from the example code where

问题 The following Python program should draw a white triangle in the upper right quadrant of the window. import pygame from OpenGL.GL import * from ctypes import * pygame.init () screen = pygame.display.set_mode ((800,600), pygame.OPENGL|pygame.DOUBLEBUF, 24) glViewport (0, 0, 800, 600) glClearColor (0.0, 0.5, 0.5, 1.0) glEnableClientState (GL_VERTEX_ARRAY) vertices = [ 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0 ] vbo = glGenBuffers (1) glBindBuffer (GL_ARRAY_BUFFER, vbo) glBufferData (GL_ARRAY

问题 I'm working through the excellent tutorials at arcsynthesis while building a graphics engine and have discovered I don't understand VAOs as much as I thought I had. From the tutorial Chapter 5. Objects In Depth Buffer Binding and Attribute Association You may notice that glBindBuffer(GL_ARRAY_BUFFER) is not on that list, even though it is part of the attribute setup for rendering. The binding to GL_ARRAY_BUFFER is not part of a VAO because the association between a buffer object and a vertex

问题 can I safely use the glm::* types (e.g. vec4, mat4) to fill a vertex buffer object ? std::vector<glm::vec3> vertices; glBufferData(GL_ARRAY_BUFFER, sizeof(glm::vec3) * vertices.size(), &vertices[0], GL_STATIC_DRAW); I'm not quite sure about that since struct padding (member alignment) could cause some trouble in my opinion, though all compilers I've tested returns the expected sizes. I'm developing for C++11 Compilers (maybe this make a difference). 回答1: Define "safe". C++ gives

问题 I've just read through a tutorial about Vertex Array Objects and Vertex Buffer Objects, and I can't work out from the following code how OpenGL knows the first VBO ( vertexBufferObjID[0] ) represents vertex coordinates, and the second VBO ( vertexBufferObjID[1] ) represents colour data? glGenBuffers(2, vertexBufferObjID); // VBO for vertex data glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObjID[0]); glBufferData(GL_ARRAY_BUFFER, 9*sizeof(GLfloat), vertices, GL_STATIC_DRAW); glVertexAttribPointer