#version 330 core

// linear sampling gaussian blur (kernel size : 9)
// from http://rastergrid.com/blog/2010/09/efficient-gaussian-blur-with-linear-sampling

uniform sampler2DRect colorSampler;

layout(location = 0)out vec4 outColor;

uniform int width;
uniform int height;

void main(void)
{
    //vec3 color = vec3(0);
    vec3 color = texelFetch(colorSampler, ivec2(gl_FragCoord.x/width, gl_FragCoord.y/height)).xyz * 0.2270270270;
#ifdef HORIZONTAL_BLUR
    float y = gl_FragCoord.y/height;
    color += texture(colorSampler, vec2((gl_FragCoord.x + 1.3846153846)/width, y)).xyz  * 0.3162162162;
    color += texture(colorSampler, vec2((gl_FragCoord.x - 1.3846153846)/width, y)).xyz  * 0.3162162162;
    color += texture(colorSampler, vec2((gl_FragCoord.x + 3.2307692308)/width, y)).xyz  * 0.0702702703;
    color += texture(colorSampler, vec2((gl_FragCoord.x - 3.2307692308)/width, y)).xyz  * 0.0702702703;
#else
    float x = gl_FragCoord.x/width;
    color += texture(colorSampler, vec2(x, (gl_FragCoord.y + 1.3846153846)/height)).xyz * 0.3162162162;
    color += texture(colorSampler, vec2(x, (gl_FragCoord.y - 1.3846153846)/height)).xyz * 0.3162162162;
    color += texture(colorSampler, vec2(x, (gl_FragCoord.y + 3.2307692308)/height)).xyz * 0.0702702703;
    color += texture(colorSampler, vec2(x, (gl_FragCoord.y - 3.2307692308)/height)).xyz * 0.0702702703;
#endif
    outColor = vec4(color, 1.0);
}