   Quick question on SetStreamSource
  I have two vertex buffers. Let's call them A and B. A contains vertex positions, B contains texture coordinates.Sometimes the positions change, but the texture coordinates never change. I want to be able to update the positions while avoiding wasting bandwidth on overwriting the texture coordinates. Can I do something like this:SetStreamSource(0, A, 0, sizeof(vertex));SetStreamSource(1, B, 0, sizeof(texcoord));DrawPrimitive(D3DPT_TRIANGLELIST, 0, tricount); // DrawPrimitive should now assemble A and B.Help deeply appreciated. [smile] (Google and MSDN were surprisingly unhelpful).   
  As long as your vertex declaration is setup to take into account the data for the texture coordinates is coming from the second stream that should work just fine.   ;  I see. So how would I do that in HLSL, is there like a semantic? An FVF flag for the fixed-function pipeline?I've actually been doing OpenGL for a while, but I just started learning D3D, so I'm a bit confused about the new keywords and function names.Thanks again.   ;Quote:Original post by polymorphedI see. So how would I do that in HLSL, is there like a semantic? An FVF flag for the fixed-function pipeline?I've actually been doing OpenGL for a while, but I just started learning D3D, so I'm a bit confused about the new keywords and function names.Thanks again.If you're using FVF codes, you can't specify the stream that components should come from. If you're using Vertex Declarations (Which I'd strongly recommend if you're using shaders, since it's clearer what format the vertices are in), then one of the parameters for each component is the stream index to use.   