final04_BLURFP.fsh

//
#version 130

uniform sampler2D sampler0;

vec4 TexCoord0 = gl_TexCoord[0];

const float blurSize = 1.0 / 512.0; // I've chosen this size because this will result in that every step will be one pixel wide if the RTScene texture is of size 512x512

void
main (void)
{
    vec4 baseColor = texture2D (sampler0, TexCoord0.st);

#ifdef BLUR_FP

    vec4 sum = vec4 (0.0);

    // blur in y (vertical)
    // take nine samples, with the distance blurSize between them
    sum +=
        texture2D (sampler0,
                   vec2 (TexCoord0.x - 4.0 * blurSize, TexCoord0.y)) * 0.05;
    sum +=
        texture2D (sampler0,
                   vec2 (TexCoord0.x - 3.0 * blurSize, TexCoord0.y)) * 0.09;
    sum +=
        texture2D (sampler0,
                   vec2 (TexCoord0.x - 2.0 * blurSize, TexCoord0.y)) * 0.12;
    sum +=
        texture2D (sampler0,
                   vec2 (TexCoord0.x - blurSize, TexCoord0.y)) * 0.15;
    sum += texture2D (sampler0, vec2 (TexCoord0.x, TexCoord0.y)) * 0.16;
    sum +=
        texture2D (sampler0,
                   vec2 (TexCoord0.x + blurSize, TexCoord0.y)) * 0.15;
    sum +=
        texture2D (sampler0,
                   vec2 (TexCoord0.x + 2.0 * blurSize, TexCoord0.y)) * 0.12;
    sum +=
        texture2D (sampler0,
                   vec2 (TexCoord0.x + 3.0 * blurSize, TexCoord0.y)) * 0.09;
    sum +=
        texture2D (sampler0,
                   vec2 (TexCoord0.x + 4.0 * blurSize, TexCoord0.y)) * 0.05;

    baseColor = sum;
#endif

    gl_FragColor = baseColor;
}