//---------------------------------------------------------------------------
//
//	File: Rec709.fs
//
//  Abstract: Rec 709 color correction fragment shader
// 			 
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//---------------------------------------------------------------------------

uniform sampler2DRect tex;

uniform float  gamma;
uniform mat3   displayMat;
uniform mat3   rec709MatInv;
uniform mat3   d65CAMat;

float Rec709TransferFunc(const float lRec709)
{
	float nlRec709 = 0.0;
	
	if( lRec709 <= 0.018 )
	{
		nlRec709 = 4.5 * lRec709;
	} // if
	else if( lRec709 > 0.018 )
	{
		nlRec709 = 1.099 * pow(lRec709,0.45) - 0.099;
	} // else if
	
	return( nlRec709 );
} // Rec709TransferFunc

void main( void )
{
	vec4 sample = texture2DRect(tex, gl_TexCoord[0].st);

	vec3 color;
	
	color.r = pow( sample.r, gamma );
	color.g = pow( sample.g, gamma );
	color.b = pow( sample.b, gamma );
			
	vec3 srcCIE;
	
	srcCIE.x = displayMat[0][0] * color.r + displayMat[1][0] * color.g + displayMat[2][0] * color.b;
	srcCIE.y = displayMat[0][1] * color.r + displayMat[1][1] * color.g + displayMat[2][1] * color.b;
	srcCIE.z = displayMat[0][2] * color.r + displayMat[1][2] * color.g + displayMat[2][2] * color.b;
	
	vec3 dstCIE;

	dstCIE.x = d65CAMat[0][0] * srcCIE.x + d65CAMat[0][1] * srcCIE.y + d65CAMat[0][2] * srcCIE.z;
	dstCIE.y = d65CAMat[1][0] * srcCIE.x + d65CAMat[1][1] * srcCIE.y + d65CAMat[1][2] * srcCIE.z;
	dstCIE.z = d65CAMat[2][0] * srcCIE.x + d65CAMat[2][1] * srcCIE.y + d65CAMat[2][2] * srcCIE.z;

	vec3 lRec709;
	
	lRec709.r = rec709MatInv[0][0] * dstCIE.x + rec709MatInv[1][0] * dstCIE.y + rec709MatInv[2][0] * dstCIE.z;
	lRec709.g = rec709MatInv[0][1] * dstCIE.x + rec709MatInv[1][1] * dstCIE.y + rec709MatInv[2][1] * dstCIE.z;
	lRec709.b = rec709MatInv[0][2] * dstCIE.x + rec709MatInv[1][2] * dstCIE.y + rec709MatInv[2][2] * dstCIE.z;

	vec3 nlRec709;
	
	nlRec709.r = Rec709TransferFunc(lRec709.r);
	nlRec709.g = Rec709TransferFunc(lRec709.g);
	nlRec709.b = Rec709TransferFunc(lRec709.b);

	gl_FragColor = vec4( nlRec709, 1.0 );
} // main
