source: code/branches/tutorial/Tutorial/Media/DeferredShadingMedia/DeferredShading/post/hlsl/vs.hlsl @ 25

/******************************************************************************
Copyright (c) W.J. van der Laan

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this software  and associated documentation files (the "Software"), to deal in 
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The above copyright notice and this permission notice shall be included in all copies 
or substantial portions of the Software.

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******************************************************************************/
/** Deferred shading framework
        // W.J. :wumpus: van der Laan 2005 //
        
        Post shader: Generic fullscreen quad
*/
struct VS_OUTPUT {
   float4 Pos: POSITION;
   float2 texCoord: TEXCOORD0;
   float3 projCoord: TEXCOORD1;
};
float4x4 invProj;

VS_OUTPUT main(float4 Pos: POSITION){
   VS_OUTPUT Out;

        // Clean up inaccuracies
        Pos.xy = sign(Pos.xy);

        Out.Pos = float4(Pos.xy, 0, 1);
        
        // Image-space
        Out.texCoord.x = 0.5 * (1 + Pos.x);
        Out.texCoord.y = 0.5 * (1 - Pos.y);
   
        // Projection coordinates
        // Inverted projection matrix
        // These interpolate over the frustrum plane for w=1
    Out.projCoord = float3(Pos.x, Pos.y, 1) *
                float3(
                        invProj[0][0], // X vector component from X
                        invProj[1][1], // Y vector component from Y
                        invProj[2][3]  // Z vector component from W
                );

        return Out;
}