Quote:Original post by therealremi
Is it possible with DirectX fixed pipeline multitexturing to get this effect:
texture A is blended with texture B using monochrome single channel texture C as a mask?
All textures have different mapping sets.
I couldn't find any piece of code that does the above. I saw a solution that assumes texture C is an alpha channel of texture B but this is not the way to go.

Quote:Original post by Evil Steve
Assuming I'm right, and it's not possible, is there a reason you can't update one of the first textures to write the monochrome texture into the alpha channel, and then blend them normally?

Texture[0]=(textureA);Texture[1]=(textureB);Texture[2]=(textureC);ColorOp[0]=SELECTARG1;ColorArg1[0]=TEXTURE;AlphaOp[0]=SELECTARG1;AlphaArg1[0]=CURRENT;ResultArg[0]=TEMP;ColorOp[1]=SELECTARG1;ColorArg1[1]=TEXTURE;AlphaOp[1]=SELECTARG1;AlphaArg1[1]=CURRENT;ColorOp[2]=BLENDTEXTUREALPHA;ColorArg1[2]=CURRENT;ColorArg2[2]=TEMP;AlphaOp[2]=SELECTARG1;AlphaArg1[2]=TEXTURE;ColorOp[3]=DISABLE;AlphaOp[3]=DISABLE;

Quote:Original post by Zipster
The first problem with this approach is that it makes use of the TEMP register, which is something that needs to be checked through the D3DPMISCCAPS_TSSARGTEMP device cap. Second is that it messes up your result argument state for the first texture stage. That's something that usually isn't touched and I assume wouldn't be reset back to CURRENT in any of your other shaders. So you might need a quick code "hack" that resets it after the draw call.

Quote:Original post by therealremi
The bad news is that I can't set D3DTSS_RESULTARG in the API I'm using (I don't have direct acess to DirectX functions). I can only call:
virtual bool SetTextureColorOp (DWORD stage, DWORD colorOp)=0
virtual bool SetTextureColorArg (DWORD stage, DWORD argNum, DWORD colorArg)=0
virtual bool SetTextureAlphaOp (DWORD stage, DWORD alphaArg)=0
virtual bool SetTextureAlphaArg (DWORD stage, DWORD argNum, DWORD alphaArg)=0

:(

Texture[0]=(textureA);Texture[1]=(textureC);Texture[2]=(textureB);Constant=0x00000000;ColorOp[0]=SELECTARG1;ColorArg1[0]=TEXTURE;AlphaOp[0]=SELECTARG1;AlphaArg1[0]=CURRENT;ColorOp[1]=BLENDTEXTUREALPHA;ColorArg1[1]=CURRENT;ColorArg2[1]=CONSTANT;AlphaOp[1]=SELECTARG1;AlphaArg1[1]=TEXTURE;ColorOp[2]=MODULATEINVALPHA_ADDCOLOR;ColorArg1[2]=CURRENT;ColorArg2[2]=TEXTURE;AlphaOp[2]=SELECTARG1;AlphaArg1[2]=CURRENT;