Why cudaGLSetGLDevice failed, even though it's called in the first line of main function

Question

I want to use interoperability between OpenGL and CUDA. I know, as some tutorials said, the first step is to choose device. However, when I called the cudaGLSetGLDevice(0) in the first line of the main function, the program exited with the information "cudaSafeCall() Runtime API error 36: cannot set while device is active in this process."

Actually, even though I use cudaDeviceProp and cudaChooseDevice before calling cudaGLSetDevice, the error still exists.

Believe me, my computer just has one GPU, 9800GT. And I do know that the calling of cudaGLSetGLDevice should be prior to any other CUDA function so that's why I put it in the first line of main function.

And I use the Windows SDK to render OpenGL instead of glut, is problem about this?

Answer 1

You need in opengl context initialized before call cudaGLSetDevice. In case of glut glutInit(argc, argv); is called. Initialize opengl context before use any cuda<->opengl interoperability functions call.