   The relationship between blendState and textureStageState
  I use D3D fixed func to render a model, blend multiple textures onto one primitives in a single pass, the code looks like this:SetTexture(0, firstTex);SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_SELECTARG1);SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TEXTURE);SetTexture(1, secondTex);SetTextureStageState(1, D3DTSS_COLOROP,   D3DTOP_ADD);SetTextureStageState(1, D3DTSS_COLORARG1, D3DTA_TEXTURE);SetTextureStageState(1, D3DTSS_COLORARG2, D3DTA_CURRENT)SetTexture(2, thirdTex);SetTextureStageState(....);The above code could work, But I want to know, The following code where to use? in multi texture blending, Does following func useful or how to use ?SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);SetRenderState(D3DRS_SRCBLEND, D3DBLEND_ONE);SetRenderState(D3DRS_DESTBLEND, D3DBLEND_ZERO);    
  The blend states you listed here are used to blend the result of the pixel pipeline with the current frame buffer value. Most times they are used for transparency effects.  It’s although possible to emulate multitexture techniques with this. It’s called multipass in this case. But for performances reason this should only be done when it’s not possible to calculate the final pixel color in a single pass with the texture stages or a pixel shader.   ;  First the texture stages run.  After the last stage, the result is either written to the framebuffer, or blended with the framebuffer, depending on if you have ALPHABLENDENABLE set.  SrcBlend, DestBlend, and BlendOp control how the blending operates.NewColor is the result of the texture stages or pixel shader.PreviousColor is what's already in the frame buffer.FinalColor is the new value that gets written in the frame buffer.The blending takes the form of:  FinalColor = SrcBlend * NewColor (BLENDOP) DestBlend * PreviousColorYour example stages would then be:  FinalColor = 1 * NewColor + 0 * PreviousColorThis result is exactly what you would get with blending disabled (ie: it will write the NewColor to the frame buffer).  This particular blend state setup accomplishes nothing, aside from potentially slowing down rendering.