uniform float tau = 6.2832;
extern bool paused;
extern bool gameover;
extern float width;
extern float height;
extern float time;
vec3 hue2rgb(float hue) {
    hue = mod(hue, 360);
    vec3 rgb = vec3(0, 0, 0);
    float hdash = hue / 60.0;
    float n = 1 * (1.0 - abs((mod(hdash, 2.0)) - 1.0));
    if(hdash < 1.0) {
        rgb.r = 1;
        rgb.g = n;
    } else if(hdash < 2.0) {
        rgb.r = n;
        rgb.g = 1;
    } else if(hdash < 3.0) {
        rgb.g = 1;
        rgb.b = n;
    } else if(hdash < 4.0) {
        rgb.g = n;
        rgb.b = 1;
    } else if(hdash < 5.0) {
        rgb.r = n;
        rgb.b = 1;
    } else if(hdash <= 6.0) {
        rgb.r = 1;
        rgb.b = n;
    }
    return rgb;
}
vec4 effect(vec4 color, Image texture, vec2 texture_coords, vec2 pixel_coords) {
    vec4 pixel = texture2D(texture, vec2(texture_coords.x, texture_coords.y));
    if(pixel.a == 1) {
        pixel.r = pixel.g = pixel.b = 1;
        //pixel.r = texture_coords.x;
        //pixel.b = texture_coords.y;
        pixel.a = 1;
    } else if(pixel.a == 0) {
        if(gameover) {
            pixel.r = texture_coords.y * 0.05 + 0.1;
        } else if(paused) {
            pixel.g = texture_coords.y * 0.05 + 0.1;
            pixel.b = texture_coords.y * 0.10 + 0.1;
        }
        int offset = 10;
        int iterations = 25;
        float intensity = 0.03;
        for(float ang = tau / iterations; ang < tau; ang += tau / iterations) {
            float dx = cos(ang) * offset / width;
            float dy = sin(ang) * offset / height;
            vec4 target = texture2D(texture, vec2(texture_coords.x + dx, texture_coords.y + dy));

            if(target.b == 1) {
                pixel += vec4(hue2rgb(time * 200) * intensity, 1.0);
            }

            if(target.r == 1) {
                pixel.r += intensity;
                pixel.g += intensity;
                pixel.b += intensity;
            }
        }
        pixel.a = 1;
    } else {
    }
    return pixel;
}