https://msdn.microsoft.com/zh-cn/library/windows/desktop/bb173595(v=vs.85).aspx
void OMSetBlendState( [in] ID3D10BlendState *pBlendState, [in] const FLOAT BlendFactor[4], [in] UINT SampleMask );
the second is about blendfactor.......
| RenderTargetWriteMask[8] | D3D10_COLOR_WRITE_ENABLE_ALL[8] |
set colormask in this way
RenderTargetWrite Mask[8]; D3D10_COLOR_WRITE_ENABLE_ALL[8]
原文：http://www.cnblogs.com/minggoddess/p/4315899.html