#version 130

#define pi 3.141592654

in vec2 fragTexCoord;
in vec4 fragColor;
uniform sampler2D texture0;
uniform vec4 colDiffuse;
out vec4 finalColor;

vec3 to_focus(float pixel)
{
    pixel = mod(pixel + 3.0, 3.0);
    if (pixel >= 2.0) return vec3(pixel - 2.0, 0.0, 3.0 - pixel); // Blue
    else if (pixel >= 1.0) return vec3(0.0, 2.0 - pixel, pixel - 1.0); Green
    else return vec3(1.0 - pixel, pixel, 0.0); // Red
}

void main()
{
    vec2 textureSize = vec2(160.0, 144.0);
    float y = mod(fragTexCoord.y * textureSize.y, 1.0);
    float intensity = exp(-0.4 * y);
    vec2 one_x = vec2(1.0 / (10.0 * textureSize.x), 0.0);
    vec3 color = texture(texture0, fragTexCoord - 0.0 * one_x).rgb;
    vec3 color_prev = texture(texture0, fragTexCoord - 1.0 * one_x).rgb;
    vec3 color_prev_prev = texture(texture0, fragTexCoord - 2.0 * one_x).rgb;
    float pixel_x = 3.0 * fragTexCoord.x * textureSize.y;
    vec3 focus = to_focus(pixel_x - 0.0);
    vec3 focus_prev = to_focus(pixel_x - 1.0);
    vec3 focus_prev_prev = to_focus(pixel_x - 2.0);
    vec3 result = 0.8 * color * focus + 0.6 * color_prev * focus_prev + 0.2 * color_prev_prev * focus_prev_prev;
    result = 1.6 * pow(result, vec3(1.0));
    finalColor = vec4((intensity) * result, 1.0);
}