#vertex

void main() {
    gl_TexCoord[0] = gl_MultiTexCoord0;
    gl_Position = ftransform();
}

#fragment

uniform float r;
uniform sampler2D tex;
const vec2 d1 = vec2(0.0, 0.4);
const vec2 d2 = vec2(0.0, 0.8);
const vec2 d3 = vec2(0.0, 1.2);
const vec2 d4 = vec2(0.0, 1.6);

void main() {
    vec2 tc = vec2(gl_TexCoord[0]);
    gl_FragColor = 0.200 * texture2D(tex, tc)
                 + 0.181 * (texture2D(tex, tc + d1 * r)
                           +texture2D(tex, tc - d1 * r))
                 + 0.131 * (texture2D(tex, tc + d2 * r)
                           +texture2D(tex, tc - d2 * r))
                 + 0.069 * (texture2D(tex, tc + d3 * r)
                           +texture2D(tex, tc - d3 * r))
                 + 0.019 * (texture2D(tex, tc + d4 * r)
                           +texture2D(tex, tc - d4 * r));
}