Hi J.P.,
Thanks for your interest in using osgCompute. First of all it is possible as
long as your previous texture is of type osgCuda::TextureXD. There is currently
no way to use osg::Textures directly. The specialization is necessary as we
need to keep track of when the texture's apply( State ) method is called within
the osg pipeline. If you have utilized a osg::Texture2D beforehand it is no
problem to switch to a osgCuda::Texture2D as it acts like a osg::Texture2D as
long as no CUDA operation is performed.
If you utilize a osgCuda::Texture2D for example, you can use myTexture->map(
osgCompute::MAP_DEVICE_SOURCE ) or myTexture->map( osgCompute::MAP_DEVICE_ARRAY
). However as CUDA maps an OpenGL texture to a cudaArray* we internally copy
the array's data to writeable device memory with a cudaMemcpyDeviceToDevice in
case of MAP_DEVICE_SOURCE. Its fast (GPU->GPU) but still it is a copy
operation. If you want to avoid any copy operation you should use
MAP_DEVICE_ARRAY. This will return the cudaArray pointer directly. The decision
which of them to use depends on which type of pointer your CUDA-kernel supports:
MAP_DEVICE_SOURCE:
Code:
...
cudaKernel<<< #blocks,#threads >>>( (float*)
myTexture->map(osgCompute::MAP_DEVICE_SOURCE ) );
...
__global__ void cudaKernel( float* myPtr ) {
...
float val = myPtr[122];
...
}
MAP_DEVICE_ARRAY:
Code:
...
cudaBindTextureToArray( myTex,
(cudaArray*)(myTexture->map(osgCompute::MAP_DEVICE_ARRAY ) ) );
...
cudaKernel<<< #blocks,#threads >>>();
...
__global__ void cudaKernel(){
...
float val = texture2D(0.3,0.3,myTex);
...
}
Please notice that we currently only support single-threaded osg applications.
Best regards,
Jens[/code]
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=35680#35680
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