//**************************************************************************/
// Copyright 2014 Autodesk, Inc.
// All rights reserved.
// Use of this software is subject to the terms of the Autodesk license
// agreement provided at the time of installation or download, or which
// otherwise accompanies this software in either electronic or hard copy form.
//**************************************************************************/

#include "Common.ogsfh"

uniform int gIterate = 50;

uniform float gScale = 0.423;

uniform float gCenterX = 0.0f;

uniform float gCenterY = 0.379f;

uniform float gRange = 0.05f;

uniform vec3 gInColor = {0.05,0.225,0.3};

uniform vec3 gOutColorA = {0.4,0.6,0.9};

uniform vec3 gOutColorB = {1,0.8,0.1};

/////////////////////////////////////////////////////

// Pixel shader.
// NOTE: This expects screen quad vertex shader output.
GLSLShader PS_Mandelbrot
{
	void main()
	{
		vec2 pos = VSUV.xy; // fract(VSUV.xy);
		pos.y = 1 - pos.y;
		float real = pos.x *gScale + (gCenterX);
		float imag = pos.y *gScale + (gCenterY);
		float Creal = real;
		float Cimag = imag;
		Creal = -0.765f;
		Cimag = 0.11f;
		float r2 = 0.0f;
		float i;
		for (i=0; (i<gIterate) && (r2<4.0); i++) {
			float tempreal = real;
			real = (tempreal*tempreal) - (imag*imag) + Creal;
			imag = 2.0*tempreal*imag + Cimag;
			r2 = (real*real) + (imag*imag);
		}
		vec3 finalColor;
		if (r2 < 4.0f) {
		   finalColor = gInColor;
		} else {
			finalColor = lerp(gOutColorA,gOutColorB, fract(i * gRange));
		}
		colorOut = vec4(finalColor,0);
	}
}

// Main technique.
technique Main
{
    pass p0
    {
        VertexShader (in VS_INPUT_ScreenQuad, out VS_TO_PS_ScreenQuad) = VS_ScreenQuad;
        PixelShader (in VS_TO_PS_ScreenQuad, out pixelOut) = PS_Mandelbrot;
    }
}