#pragma header

uniform float _hue;
uniform float _sat;
uniform float _val;

vec3 normalizeColor(vec3 color)
{
    return vec3(
        color[0] / 255.0,
        color[1] / 255.0,
        color[2] / 255.0
    );
}

vec3 rgb2hsv(vec3 c)
{
    vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
    vec4 p = mix(vec4(c.bg, K.wz), vec4(c.gb, K.xy), step(c.b, c.g));
    vec4 q = mix(vec4(p.xyw, c.r), vec4(c.r, p.yzx), step(p.x, c.r));
    float d = q.x - min(q.w, q.y);
    float e = 1.0e-10;
    return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + e)), d / (q.x + e), q.x);
}

vec3 hsv2rgb(vec3 c)
{
    vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
    vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
    return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
}

void main() {
  vec4 color = flixel_texture2D(bitmap, openfl_TextureCoordv);
  vec4 swagColor = vec4(rgb2hsv(vec3(color[0], color[1], color[2])), color[3]);
  swagColor.x *= _hue;
  swagColor.y *= _sat;
  swagColor.z *= _val;
  // approximate "lightness" changing!!
  swagColor.z *= (_hue * 0.5) + 0.5;
  color = vec4(hsv2rgb(vec3(swagColor[0], swagColor[1], swagColor[2])), swagColor[3]);
	gl_FragColor = color;
}