vbo

Closed . This question needs to be more focused . It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post . Closed last year . I have a model designed in Blender that i am going to render, in my game engine built using opengl, after exporting it to collada. The model in blender is divided into groups. These groups contains vertices normals and textures with there own index. is it a good thing to do if i rendered each group as a separate vbo or should i render the whole model as a single vbo? Rules of thumb

I have recently migrated from a 32bit environment to a 64bit one, and it has gone smoothly apart from one problem: glMultiDrawElements uses some arrays that do not work without some tweaking under a 64bit OS. glMultiDrawElements( GL_LINE_LOOP, fCount_, GL_UNSIGNED_INT, reinterpret_cast< const GLvoid** >( iOffset_ ), mesh().faces().size() ); I am using VBOs for both the vertices and vertex indices. fCount_ and iOffset_ are arrays of GLsizei . Since a buffer is bound to GL_ELEMENT_ARRAY_BUFFER , iOffset_ 's elements are used as byte offsets from the VBO beginning. This works perfectly under a

Given a vertex shader that looks something like #version 400 compatibility const int max_valence = 6; in int valence; in vec3 patch_data[1 + 2 * max_valence]; ... What is the the proper way to map the data to the correct vertex attribs? I'm trying to use a VBO, but I can't figure out how to pass that large of a value in. glVertexAttribPointer takes at most a vector of size 4. What's the correct way to get the vertex attributes into the shader? Arrays of vertex attributes are legal in OpenGL. However, each member of the array takes up a separate attribute index. They are allocated contiguously,

So I've been trying to teach myself to use VBOs, in order to boost the performance of my OpenGL project and learn more advanced stuff than fixed-function rendering. But I haven't found much in the way of a decent tutorial; the best ones I've found so far are Songho's tutorials and the stuff at OpenGL.org , but I seem to be missing some kind of background knowledge to fully understand what's going on, though I can't tell exactly what it is I'm not getting, save the usage of a few parameters. In any case, I've forged on ahead and come up with some cannibalized code that, at least, doesn't crash,

Sample code: 1. glGenBuffers(1, &VboId); 2. glBindBuffer(GL_ARRAY_BUFFER, VboId); 3. glBufferData(GL_ARRAY_BUFFER, sizeof(Vertices), Vertices, GL_STATIC_DRAW); 4. glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, 0); So we generate a generic VBO handle, and then we bind it using "GL_ARRAY_BUFFER". Binding it seems to have 2 purposes: We must bind the buffer before we can copy data to the GPU via glBufferData We must bind the buffer before we can add attributes to it via glVertexAttribPointer And I think those are the only 2 times you need to bind the VBO. My question is, is there any scenario

I'm creating a CAD-like app (Qt-based), it will be a multiple document interface and each document will contain about 5 viewports (derived from QGLWidget). As such I need my flat shader to be shared across the entire application, and then the 3D assets (models stored as VBOs) to be shared across each document i.e. the 5 viewports. I thought as long as I shared around the shader program and VBO GLuint addresses all will automagickly work - it doesn't. I think because each viewport/context has it's own address space on the graphics card, if anyone knows better please inform! I would like to have

I am a desktop GL developer, and I am starting to explore the mobile world. To avoid misunderstandings, or welcome-but-trivial replies, I can humbly say that I am pretty well aware of the GL and GL|ES machinery. The short question is: if we are using GL|ES 2.0 in a shared memory architecture, what's the point behind using VBOs against client-side arrays? More in detail: Vertex buffers are raw chunks of memory, the driver cannot in any way optimize anything because the access pattern depends on: 1) how the application configures vertex data layout, 2) how a vertex shader consumes buffer content

I'm trying to copy vertex data from a texture to a vertex buffer, and then draw the vertex buffer. As far as I know the best way to do this is to bind the texture to a fbo, and use glReadPixels to copy it to a vbo. However, I can't seem to get this working: glReadPixels fails with the error "invalid operation". Corrections, examples and alternate methods welcome. :) Here's the relevant code: glEnable(GL_TEXTURE_2D) w, h = 32, 32 vbo = glGenBuffers(1) glBindBuffer(GL_ARRAY_BUFFER, vbo) glBufferData(GL_ARRAY_BUFFER, sizeof(c_float)*w*h*4, None, GL_STREAM_COPY) glBindBuffer(GL_ARRAY_BUFFER, 0)