blur.glsl

precision mediump float;

uniform sampler2D buffer, vid;
uniform vec2 dims;

varying vec2 uv;

void main() {
    vec2 offs = vec2(1. / dims.x, 1. / dims.y);

    vec2 src = uv.st;

    vec2 tc4 = src;

    float width = 0.6;
    vec2 tc1 = src + vec2(0.0, -offs.t * width);
    vec2 tc3 = src + vec2(-offs.s * width, 0.0);
    vec2 tc5 = src + vec2(offs.s * width, 0.0);
    vec2 tc7 = src + vec2(0.0, offs.t * width);

    vec2 tc0 = src + vec2(-offs.s * width, -offs.t * width);
    vec2 tc2 = src + vec2( offs.s * width, -offs.t * width);
    vec2 tc6 = src + vec2(-offs.s * width,  offs.t * width);
    vec2 tc8 = src + vec2( offs.s * width,  offs.t * width);

    vec4 col0 = texture2D(buffer, tc0);
    vec4 col1 = texture2D(buffer, tc1);
    vec4 col2 = texture2D(buffer, tc2);
    vec4 col3 = texture2D(buffer, tc3);
    vec4 col4 = texture2D(buffer, tc4);
    vec4 col5 = texture2D(buffer, tc5);
    vec4 col6 = texture2D(buffer, tc6);
    vec4 col7 = texture2D(buffer, tc7);
    vec4 col8 = texture2D(buffer, tc8);

    gl_FragColor = (2.0 * col0 + 1.0 * col1 + 2.0 * col2 
                  + 1.0 * col3 + 4.0 * col4 + 1.0 * col5
                  + 2.0 * col6 + 1.0 * col7 + 2.0 * col8) / 16.0;

}