source: GTP/trunk/Lib/Vis/Preprocessing/src/dual_depth.cg @ 540

struct fragment
{
        float4 position  : POSITION;    //screen position
        float4 color0    : COLOR0;
        float4 depthTexCoord: TEXCOORD0;
};


struct pixel
{
        float4 color : COLOR;   
};

pixel main(fragment IN, const uniform sampler2D depthMap)
{
        pixel OUT;
        OUT.color = IN.color0;
        
        // the depth buffer     has to be compared to the current depth
        float4 depth = tex2D(depthMap, IN.depthTexCoord.xy);
        float test = IN.depthTexCoord.z / IN.depthTexCoord.w;
        
        // reject by alpha test
        if (test < depth.x)
        {
                OUT.color.w = 0;
        //      OUT.color.y += 0.5;
        }
        
        return OUT;
}