SetVertexDeclaration()和SetFVF()

IDirect3DDevice9::SetVertexDeclaration

Sets a Vertex Declaration (Direct3D 9).

HRESULT SetVertexDeclaration(
  IDirect3DVertexDeclaration9 * pDecl
);

Parameters

pDecl

[in] Pointer to an IDirect3DVertexDeclaration9 object, which contains the vertex declaration.

Return Values

If the method succeeds, the return value is D3D_OK. The return value can be D3DERR_INVALIDCALL.

Remarks

A vertex declaration is an IDirect3DVertexDeclaration9 object that defines the data members of a vertex (i.e. texture coordinates, colors, normals, etc.). This data can be useful for implementing vertex shaders and pixel shaders.

Requirements

Header: Declared in D3D9.h.

See Also

IDirect3DDevice9::GetVertexDeclaration

IDirect3DDevice9::SetFVF

Sets the current vertex stream declaration.

HRESULT SetFVF(
  DWORD FVF
);

Parameters

FVF

[in] DWORD containing the fixed function vertex type. For more information, see D3DFVF.

Return Values

If the method succeeds, the return value is D3D_OK. If the method fails, the return value can be: D3DERR_INVALIDCALL.

Remarks

Here are the steps necessary to initialize and use vertices that have a position, diffuse and specular color, and texture coordinates:

1. Define the custom vertex type and FVF code.

   struct LVertex
   {
       FLOAT    x, y, z;
       D3DCOLOR specular, diffuse;
       FLOAT    tu, tv;
   };
       
   const DWORD VertexFVF = (D3DFVF_XYZ | D3DFVF_DIFFUSE |
                            D3DFVF_SPECULAR | D3DFVF_TEX1 );
   

2. Create a vertex buffer with enough room for four vertices using IDirect3DDevice9::CreateVertexBuffer.

   g_d3dDevice->CreateVertexBuffer( 4*sizeof(LVertex),  
       D3DUSAGE_WRITEONLY, VertexFVF, D3DPOOL_DEFAULT, &pBigSquareVB, NULL );
   

3. Set the values for each vertex.

   LVertex * v;
   pBigSquareVB->Lock( 0, 0, (BYTE**)&v, 0 );
       
   v[0].x  = 0.0f;  v[0].y  = 10.0;  v[0].z  = 10.0f;
   v[0].diffuse  = 0xffff0000;
   v[0].specular = 0xff00ff00;
   v[0].tu = 0.0f;  v[0].tv = 0.0f;
       
   v[1].x  = 0.0f;  v[1].y  = 0.0f;  v[1].z  = 10.0f;
   v[1].diffuse  = 0xff00ff00;
   v[1].specular = 0xff00ffff;
   v[1].tu = 0.0f;  v[1].tv = 0.0f;
       
   v[2].x  = 10.0f; v[2].y  = 10.0f; v[2].z  = 10.0f;
   v[2].diffuse  = 0xffff00ff;
   v[2].specular = 0xff000000;
   v[2].tu = 0.0f;  v[2].tv = 0.0f;
       
   v[3].x  = 0.0f; v[3].y  = 10.0f;  v[3].z = 10.0f;
   v[3].diffuse  = 0xffffff00;
   v[3].specular = 0xffff0000;
   v[3].tu = 0.0f; v[3].tv = 0.0f;
       
   pBigSquareVB->Unlock();
   

4. The vertex buffer has been initialized and is ready to render. The following code example shows how to use the legacy FVF to draw a square.

   g_d3dDevice->SetFVF(VertexFVF);
   g_d3dDevice->SetStreamSource(0, pBigSquareVB, 0, sizeof(LVertex));
   g_d3dDevice->DrawPrimitive(D3DPT_TRIANGLESTRIP, 0 ,2);
   

Here are the steps necessary to initialize and use vertices that have a position, a normal, and texture coordinates:

1. Define the custom vertex type and FVF code.

   struct Vertex
   {
       FLOAT x, y, z;
       FLOAT nx, ny, nz;
       FLOAT tu, tv;
   };
       
   const DWORD VertexFVF = ( D3DFVF_XYZ | D3DFVF_NORMAL | D3DFVF_TEX1 );
   

2. Create a vertex buffer with enough room for four vertices using IDirect3DDevice9::CreateVertexBuffer (similar to the example above).
3. Set the values for each vertex.

   Vertex * v;
   pBigSquareVB->Lock(0, 0, (BYTE**)&v, 0);
       
   v[0].x  = 0.0f;  v[0].y  = 10.0;  v[0].z  = 10.0f;
   v[0].nx = 0.0f;  v[0].ny = 1.0f;  v[0].nz = 0.0f;
   v[0].tu = 0.0f;  v[0].tv = 0.0f;
   
   v[1].x  = 0.0f;  v[1].y  = 0.0f;  v[1].z  = 10.0f;
   v[1].nx = 0.0f;  v[1].ny = 1.0f;  v[1].nz = 0.0f;
   v[1].tu = 0.0f;  v[1].tv = 0.0f;
       
   v[2].x  = 10.0f; v[2].y  = 10.0f; v[2].z  = 10.0f;
   v[2].nx = 0.0f;  v[2].ny = 1.0f;  v[2].nz = 0.0f;
   v[2].tu = 0.0f;  v[2].tv = 0.0f;
       
   v[3].x  = 0.0f; v[3].y  = 10.0f;  v[3].z = 10.0f;
   v[3].nx = 0.0f; v[3].ny = 1.0f;   v[3].nz = 0.0f;
   v[3].tu = 0.0f; v[3].tv = 0.0f;
       
   pBigSquareVB->Unlock();
   

4. Draw the object (similar to the example above).

Requirements

Header: Declared in D3D9.h.

See Also

IDirect3DDevice9::GetFVF

无论是可编程管线还是固定管线 SetVertexDeclaration 都比 SetFVF 高效。

SetVertexDeclaration 比 SetFVF 灵活，使用可编程管线时，复杂情况下 SetFVF 是不够用的。

效果不一定一样。
比如，SetVertexDeclaration可以设定纹理坐标是2个浮点数或者3个浮点数或者4个浮点数，也可以设定法线是3个浮点数或者4个浮点数或者一个4字节整数，非常灵活，此外还有很多别的特性，都是FVF做不到的，所以两者不一定能直接转换。