As far as I know, certain mathematical functions like FFTs and perlin noise, etc. can be much faster when done on the GPU as a pixel shader. My question is, if I wanted to exploit this to calculate results and stream to bitmaps, could I do it without needing to actually display it in Silverlight or something?
More specifically, I was thinking of using this for large terrain generation involving lots of perlin and other noises, and post-processing like high passes and deriving normals from heightmaps, etc, etc.
The short answer is yes. The longer answer is that you can set (for example) a texture as the render target, which deposits your results there.
Unless you’re really set on using a shader to do the calculation, you might want to consider using something that’s actually designed for this kind of job such as Cuda or OpenCL.