4 replies to this topic

[Jeason]

Greeting!

I find many samples in DXSDK invoke SetVertexDeclaration() before using effect, and I also find it still works normally if i remove the SetVertexDeclaration.

So i want to know is it necessary to invoke SetVertexDelaration() before we use effect?

[Asesh]

If you have manually created a primitive then you must use SetVertexDeclaration. But how ever you don't have to do that when rendering geometry data from x files. Am sure those samples are x files, aren't they?

[Jeason]

Yes, the mesh is loaded from x file. Why doesn't the mesh loaded from x file need to SetVertexDeclaration?

Does the ID3DXMesh interface contain the vertex declaration stored in x file and set it in DrawSubset()?

[programci_84]

There's an exact vertex declaration equivalent for every FVF. And every mesh has a FVF property. So, you don't need to manually call IDirect3DDevice9::SetVertexDeclaration(), because ID3DXMesh::DrawSubset() function calls IDirect3DDevice9::SetVertexDeclaration() before calling SetStreamSource() and SetIndices().

[Jeason]

Get it, guys!