package;

import openfl.display.Shader;
import openfl.utils.ByteArray;

/**
 * ...
 * @author 
 */
class MandelbrotShader extends Shader 
{
	@:glVertexHeader(
		
		"attribute float openfl_Alpha;
		attribute vec4 openfl_ColorMultiplier;
		attribute vec4 openfl_ColorOffset;
		attribute vec4 openfl_Position;
		attribute vec2 openfl_TextureCoord;
		
		varying float openfl_Alphav;
		varying vec4 openfl_ColorMultiplierv;
		varying vec4 openfl_ColorOffsetv;
		varying vec2 openfl_TextureCoordv;
		
		uniform mat4 openfl_Matrix;
		uniform bool openfl_HasColorTransform;
		uniform vec2 openfl_TextureSize;"
		
	)
	
	
	@:glVertexBody(
		
		"openfl_Alphav = openfl_Alpha;
		openfl_TextureCoordv = openfl_TextureCoord;
		
		if (openfl_HasColorTransform) {
			
			openfl_ColorMultiplierv = openfl_ColorMultiplier;
			openfl_ColorOffsetv = openfl_ColorOffset / 255.0;
			
		}
		
		gl_Position = openfl_Matrix * openfl_Position;"
		
	)
	
	
	@:glVertexSource(
		
		"#pragma header
		
		void main(void) {
			
			#pragma body
			
		}"
		
	)
	
	
	@:glFragmentHeader(
		
		"varying float openfl_Alphav;
		varying vec4 openfl_ColorMultiplierv;
		varying vec4 openfl_ColorOffsetv;
		varying vec2 openfl_TextureCoordv;
		
		uniform bool openfl_HasColorTransform;
		uniform vec2 openfl_TextureSize;
		uniform sampler2D bitmap;
		
		uniform float time;"
		
	)
	
	
	@:glFragmentBody(
		
		"vec4 color = texture2D (bitmap, openfl_TextureCoordv);
		
		if (color.a == 0.0) {
			
			gl_FragColor = vec4 (0.0, 0.0, 0.0, 0.0);
			
		} else if (openfl_HasColorTransform) {
			
			color = vec4 (color.rgb / color.a, color.a);
			
			mat4 colorMultiplier = mat4 (0);
			colorMultiplier[0][0] = openfl_ColorMultiplierv.x;
			colorMultiplier[1][1] = openfl_ColorMultiplierv.y;
			colorMultiplier[2][2] = openfl_ColorMultiplierv.z;
			colorMultiplier[3][3] = 1.0; // openfl_ColorMultiplierv.w;
			
			color = clamp (openfl_ColorOffsetv + (color * colorMultiplier), 0.0, 1.0);
			
			if (color.a > 0.0) {
				
				gl_FragColor = vec4 (color.rgb * color.a * openfl_Alphav, color.a * openfl_Alphav);
				
			} else {
				
				gl_FragColor = vec4 (0.0, 0.0, 0.0, 0.0);
				
			}
			
		} else {
			
			gl_FragColor = color * openfl_Alphav;
			
		}"
		
	)
	
	// mandelbrot shader from http://glslsandbox.com/e#52266.0
	@:glFragmentSource(
		
		"#pragma header
		
		vec3 mandelbrot(vec2 p) {
			vec2 s = p;
			float d = 0.0, l;

			for (int i = 0; i < 2000; i++) {
				s = vec2(s.x * s.x - s.y * s.y + p.x, 2.0 * s.x * s.y + p.y);
				l = length(s);
				d += l + 0.2;
				if (l > 2.0) return vec3(sin(d * 0.0314), sin(d * 0.02), sin(d * 0.1));
			}
			
			return vec3(0.0);
		}
		
		void main(void) {
			
			#pragma body
			
			vec2 p = (openfl_TextureCoordv * 4.0  - 2.0) * .1;
			float f = sin(time * 0.05 + 99.0) * 0.5 + 0.5;
			p *= pow(1.5, f * (-31.0));
			p += vec2(-1.002029, 0.303864);

			gl_FragColor = vec4(mandelbrot(p), openfl_Alphav);
			
		" +
		#if emscripten
		"gl_FragColor = gl_FragColor.bgra;}"
		#else
		"}"
		#end
		
	)

	public function new(code:ByteArray=null) 
	{
		super(code);
		
	}
	
}