#version 330 core

in VS_OUT {
    vec2 tex_coords;
} vs_out;

out vec4 frag_color;

uniform sampler2D image;
uniform bool horizontal;
uniform float weights[5] = float[](0.2270270270, 0.1945945946, 0.1216216216, 0.0540540541, 0.0162162162);

void main(void)
{
    vec2 tex_offset = 1.0 / textureSize(image, 0);
    vec3 result = texture(image, vs_out.tex_coords).rgb * weights[0];
    if (horizontal) {
        for (int i = 1; i < 5; i++) {
            result += texture(image, vs_out.tex_coords + vec2(tex_offset.x * i, 0.0)).rgb * weights[i];
            result += texture(image, vs_out.tex_coords - vec2(tex_offset.x * i, 0.0)).rgb * weights[i];
        }
    } else {
        for (int i = 1; i < 5; i++) {
            result += texture(image, vs_out.tex_coords + vec2(0.0, tex_offset.y * i)).rgb * weights[i];
            result += texture(image, vs_out.tex_coords - vec2(0.0, tex_offset.y * i)).rgb * weights[i];
        }
    }
    frag_color = vec4(result, 1.0);
}