#include "common.h"
/*
struct 	v2p
{
  float4 tc0: 		TEXCOORD0;	// Central
  float4 tc1: 		TEXCOORD1;	// -1,+1
  float4 tc2: 		TEXCOORD2;	// -2,+2
  float4 tc3: 		TEXCOORD3;	// -3,+3
  float4 tc4: 		TEXCOORD4;	// -4,+4
  float4 tc5: 		TEXCOORD5;	// -5,+5
  float4 tc6: 		TEXCOORD6;	// -6,+6
  float4 tc7: 		TEXCOORD7;	// -7,+7
};
*/

//////////////////////////////////////////////////////////////////////////////////////////
uniform float4	MiddleGray;
//////////////////////////////////////////////////////////////////////////////////////////
//	perform 4x4 bilinear, 8x8p, the step (C)
//	c):	8x8p	=> 1x1p		with exp

	// native bilinear
float sample( float2 tc )
{
//	float4	data = tex2D(s_image,tc);
	float4	data = s_image.Sample( smp_rtlinear, tc );
	return 	dot( data, 1.h/4.h );	// sum components
}

float4 main ( p_filter I ) : SV_Target
{
	// sample
	float4 	accum0;
		accum0.x =	sample(I.Tex0);
		accum0.y = 	sample(I.Tex1);
		accum0.z = 	sample(I.Tex2);
		accum0.w =	sample(I.Tex3);
	float4 	accum1;
		accum1.x =	sample(I.Tex4);
		accum1.y = 	sample(I.Tex5);
		accum1.z = 	sample(I.Tex6);
		accum1.w =	sample(I.Tex7);
	float4 	accum2;
		accum2.x =	sample(I.Tex0.wz);
		accum2.y = 	sample(I.Tex1.wz);
		accum2.z = 	sample(I.Tex2.wz);
		accum2.w =	sample(I.Tex3.wz);
	float4 	accum3;
		accum3.x =	sample(I.Tex4.wz);
		accum3.y = 	sample(I.Tex5.wz);
		accum3.z = 	sample(I.Tex6.wz);
		accum3.w =	sample(I.Tex7.wz);

	// perform accumulation
	float4	final;
		final.x	= dot(accum0,1/4.h);
		final.y	= dot(accum1,1/4.h);
		final.z	= dot(accum2,1/4.h);
		final.w	= dot(accum3,1/4.h);
	float 	result	= dot(final, 1/4.h);

	// OK
	float	scale 		= MiddleGray.x / (result*MiddleGray.y + MiddleGray.z);	// final
//	float  	scale_prev	= tex2D	(s_tonemap,I.tc0).x;
	float  	scale_prev	= s_tonemap.Sample( smp_nofilter, I.Tex0 ).x;
	float 	rvalue		= lerp	(scale_prev,scale,MiddleGray.w);

//			clamp		(rvalue, 1.f/8.f, 2.0f);

			clamp		(rvalue, 1.f/128.f, 20.0f);

	return 	rvalue		;

}