source: data/data_extern/programs/Cg/SharpenEdgesFP.cg

sampler2D RT: register(s0);

float4 sharpenEdges_fp( float4 pos : POSITION, float2 iTexCoord: TEXCOORD0, uniform float2 vTexelSize) : COLOR
{

        float2 usedTexelED[8] = {
                -1, -1,
                 0, -1,
                 1, -1,
                -1,  0,
                 1,  0,
                -1,  1,
                 0,  1,
             1,  1,
        };

        float4 cAvgColor= 9 * tex2D (RT, iTexCoord);

        for(int t=0; t<8; t++)
                cAvgColor -= tex2D(RT, iTexCoord + vTexelSize * usedTexelED[t]);

        return cAvgColor;
}