//========== Copyright (c) Valve Corporation, All rights reserved. ==========//

#define HDRTYPE HDR_TYPE_NONE
#include "common_ps_fxc.h"

sampler TexSampler	: register( s0 );

struct PS_INPUT
{
	float2 coordTap0				: TEXCOORD0;
	float2 coordTap1				: TEXCOORD1;
	float2 coordTap2				: TEXCOORD2;
	float2 coordTap3				: TEXCOORD3;
};

float AlphaConst : register( c0 );

float4 main( PS_INPUT i ) : COLOR
{
	float3 s0, s1, s2, s3;

	// Sample 4 taps. We use the trick of sampling four taps with bilinear in order
	// to average 16 texels.
	s0 = tex2D( TexSampler, i.coordTap0);
	s1 = tex2D( TexSampler, i.coordTap1);
	s2 = tex2D( TexSampler, i.coordTap2);
	s3 = tex2D( TexSampler, i.coordTap3);
	float avglum=0.25*(s0.x+s1.x+s2.x+s3.x);
	float elum=exp(avglum);
	
	return FinalOutput( float4(elum,elum,elum,1), 0, PIXEL_FOG_TYPE_NONE, TONEMAP_SCALE_NONE );
}