source: data/data_extern/programs/GLSL150/SharpenEdgesFP.glsl @ 12202

#version 150

uniform sampler2D RT;
uniform vec2 vTexelSize;

in vec2 oUv0;
in vec2 oUv1;
out vec4 fragColour;

void main()
{
        vec2 usedTexelED[8];
        usedTexelED[0] = vec2(-1, -1);
        usedTexelED[1] = vec2(0, -1);
        usedTexelED[2] = vec2(1, -1);
        usedTexelED[3] = vec2(-1, 0);
        usedTexelED[4] = vec2(1, 0);
        usedTexelED[5] = vec2(-1, 1);
        usedTexelED[6] = vec2(0, 1);
        usedTexelED[7] = vec2(1, 1);

    vec4 tc = texture(RT, oUv0);
        vec4 cAvgColor = vec4(9.0 * tc);

        for(int t=0; t<8; t++)
                cAvgColor -= texture(RT, oUv0 + vTexelSize * usedTexelED[t]);

        fragColour = cAvgColor;
}