gaussx.fsh

uniform sampler2D mpass_texture;
uniform vec2      screen_texture_pow2_sz; // pow2 tex size


#define lutTex2D(v) pow(texture2D(mpass_texture, (v)),2.2)

void main()
{
    vec4 sum   = vec4(0.0);

    float wid=2.0;
    float c1 = exp(-1.0/wid/wid);
    float c2 = exp(-4.0/wid/wid);
    float c3 = exp(-9.0/wid/wid);
    float c4 = exp(-16.0/wid/wid);

    sum += lutTex2D(gl_TexCoord[0].st + vec2(-4.0,  0.0)/screen_texture_pow2_sz) * c4;
    sum += lutTex2D(gl_TexCoord[0].st + vec2(-3.0,  0.0)/screen_texture_pow2_sz) * c3;
    sum += lutTex2D(gl_TexCoord[0].st + vec2(-2.0,  0.0)/screen_texture_pow2_sz) * c2;
    sum += lutTex2D(gl_TexCoord[0].st + vec2(-1.0,  0.0)/screen_texture_pow2_sz) * c1;
    sum += lutTex2D(gl_TexCoord[0].st + vec2( 0.0,  0.0)/screen_texture_pow2_sz);
    sum += lutTex2D(gl_TexCoord[0].st + vec2(+1.0,  0.0)/screen_texture_pow2_sz) * c1;
    sum += lutTex2D(gl_TexCoord[0].st + vec2(+2.0,  0.0)/screen_texture_pow2_sz) * c2;
    sum += lutTex2D(gl_TexCoord[0].st + vec2(+3.0,  0.0)/screen_texture_pow2_sz) * c3;
    sum += lutTex2D(gl_TexCoord[0].st + vec2(+4.0,  0.0)/screen_texture_pow2_sz) * c4;

    gl_FragColor = pow(sum/(1+2*(c1+c2+c3+c4)),1.0/2.2);
}