I am rendering dynamic shadows by rendering the object to an FBO and creating a texture which gets projected onto nearby geometry. The engine is limited to re-drawing one shadow each frame, so the technique is fast and looks good.
I figure I can use a pixel shader to blur the texture when it is drawn, but I was wondering what the fastest method of blurring the texture would be, without using shaders? The shadow only gets updated when the object moves, so the blur will only be done once.
I’m thinking I should get the texture pixels, blur them myself, then feed them back to OpenGL. Any other ideas?