shader_type spatial;
render_mode unshaded, fog_disabled;

uniform sampler2D SCREEN_TEXTURE : hint_screen_texture, filter_linear_mipmap;


uniform vec3 colorCount = vec3(32); //Max HSV Count
uniform vec3 colorShift = vec3(1.0); //Shift HSV colors

uniform bool doShiftFirst = false; // do shifting colors first or flooring colors
uniform bool includeAlpha = true; // Include alpha objects. if certain objects that have alpha aren`t rendering disabling might help

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

vec3 rgb_to_hsv(vec3 color) {
	vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
	vec4 p = mix(vec4(color.bg, K.wz), vec4(color.gb, K.xy), step(color.b, color.g));
	vec4 q = mix(vec4(p.xyw, color.r), vec4(color.r, p.yzx), step(p.x, color.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);
}

void vertex()
{
	POSITION = vec4(VERTEX.xy, 1.0, 1.0);
}

void fragment() {
	vec4 tex = texture(SCREEN_TEXTURE, vec2(UV.x, -UV.y));
	vec3 hvs = rgb_to_hsv(tex.xyz);

	if (doShiftFirst){
		hvs.xyz = (hvs * colorShift);
	}

	hvs.x =  floor(hvs.x * colorCount.x) / colorCount.x;
	hvs.y =  floor(hvs.y * colorCount.y) / colorCount.y;
	hvs.z =  floor(hvs.z * colorCount.z) / colorCount.z;

	if (!doShiftFirst){
		hvs.xyz = (hvs * colorShift);
	}

	ALBEDO = hsv_to_rgb(hvs.xyz);

	if (!includeAlpha){
		ALPHA = tex.w;
	}
}