At draw time, Direct3D looks for the same "usage - usage index" combination in the current vertex declaration and the current vertex shader function. When the combination is found, the register from shader function DCL is used as the destination for the vertex element.
When a vertex element in the current vertex declaration has a usage which is not found in the current vertex shader, that vertex element is ignored.
When using a vertex shaders version less than 2.0, all semantics mentioned in the shader code need to be present in the declaration bound at draw time. When using vertex shaders 2.0 and above, this restriction that allows applications to use different vertex declarations with the same vertex shader does not exist. This is useful when a vertex shader reads input data based on static conditions. Vertex shader registers not initialized because of this will have undefined values.  回复  更多评论
  

D3DVERTEXELEMENT9 decl[] =
{
{0 ,0 ,D3DDECLTYPE_SHORT4N ,D3DDECLMETHOD_DEFAULT ,D3DDECLUSAGE_POSITION ,0},
{0 ,8 ,D3DDECLTYPE_UBYTE4 ,D3DDECLMETHOD_DEFAULT ,D3DDECLUSAGE_BLENDINDICES ,0},
{0 ,12 ,D3DDECLTYPE_UBYTE4N ,D3DDECLMETHOD_DEFAULT ,D3DDECLUSAGE_BLENDWEIGHT ,0},
{0 ,16 ,D3DDECLTYPE_UBYTE4N ,D3DDECLMETHOD_DEFAULT ,D3DDECLUSAGE_NORMAL ,0},
{0 ,20 ,D3DDECLTYPE_UBYTE4N ,D3DDECLMETHOD_DEFAULT ,D3DDECLUSAGE_TANGENT ,0},
{0 ,24 ,D3DDECLTYPE_FLOAT16_2 ,D3DDECLMETHOD_DEFAULT ,D3DDECLUSAGE_TEXCOORD ,0},
{0 ,12 ,D3DDECLTYPE_FLOAT16_2 ,D3DDECLMETHOD_DEFAULT ,D3DDECLUSAGE_TEXCOORD ,1},
D3DDECL_END()
};


vs_3_0
def c10, 3, 1, 2, -1
dcl_position v0
dcl_normal v1
dcl_tangent v2
dcl_blendindices v3
dcl_texcoord v4
dcl_position o0
dcl_texcoord o1
dcl_texcoord1 o2.xyz
dcl_texcoord2 o3.xy
dcl_texcoord3 o4.xyz
dcl_texcoord4 o5.xyz
dcl_texcoord5 o6.xyz
如果这个样子，实际又是什么意思呢？
其实输入流这个vertex buffer中具有7个members，而vertex shader只使用了其中5个members，其中blendweight和texcoord1被vs忽略掉。简单吧。  回复  更多评论
  

我的游戏不能玩了  回复  更多评论