Opengl texture to CUDA Array/texture

Accelerated Computing CUDA CUDA Programming and Performance
1

Hey, guys.

I am working on a project involving opengl and cuda.

My problems is how I can convert an opengl texture (id is known) into a cuda array, or cuda texture? So that I can deal with the data with CUDA.

Thanks.

2

Have you read through the CUDA Programming Guide? There is a whole section on CUDA/OpenGL Interoperability. Basically, you need to register/map an OpenGL buffer object so that CUDA kernels can write to it; if you’re using the driver API, start reading at page 59 (page 67 of the PDF).

3

I know how to map pbo to cuda array, but I don’t know how I pack texture to pbo. I went through the programming guide, but I didn’t find any tips about that, can you point out it?

4

There are a number of ways to do this.

PBO = pixel buffer object

FBO = framebuffer object

create PBO with appropriate size

register PBO in cuda

bind GL_PIXEL_PACK_BUFFER to PBO

bind texture to target

perform glGetTexImage on target with data pointer set to 0

unbind GL_PIXEL_PACK_BUFFER to 0

map PBO in cuda

create PBO with appropriate size

register PBO in cuda

create FBO

bind GL_FRAMEBUFFER to FBO

attach texture to COLOR_ATTACHMENT0 of FBO

bind GL_PIXEL_PACK_BUFFER to PBO

perform gReadpixels with data pointer set to 0

unbind GL_PIXEL_PACK_BUFFER to 0

bind GL_FRAMEBUFFER to 0

map PBO in cuda

3 [fastest, experimental CUDA 3.0 beta]

search the 3.0 beta reference manual for

registering:

cudaGraphicsGLRegisterImage

cudaGraphicsUnregisterResource

mapping:

cudaGraphicsMapResources

cudaGraphicsUnmapResources

cudaGraphicsSubResourceGetMappedArray : maps GL texture to cuda array

cudaGraphicsResourceGetMappedPointer: maps PBO to cuda

N.

5

Thank you very much, Nico.

And, can you tell me how to transfer data from pbo to texture? I used:

glBindTexture(GL_TEXTURE_2D, m_texture->getTexture());

glBindBufferARB(GL_PIXEL_PACK_BUFFER_ARB, m_pboId);

glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, m_width, m_height, GL_BGRA, GL_UNSIGNED_BYTE, 0);

glBindBufferARB(GL_PIXEL_PACK_BUFFER_ARB, 0);

And I got an error at:glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, m_width, m_height, GL_BGRA, GL_UNSIGNED_BYTE, 0);

6

If you transfer data TO a PBO, you have to bind the PBO to GL_PIXEL_PACK_BUFFER_ARB.

If you want to transfer FROM a PBO (like you’re trying to do) then you have to bind it to GL_PIXEL_UNPACK_BUFFER_ARB.

N.