/*=============================================================================
	LDRExtractPixelShader.usf - Extracts LDR scene color from an HDR texture
	Copyright 1998-2010 Epic Games, Inc. All Rights Reserved.
=============================================================================*/

#include "Common.usf"

SAMPLER2D(SceneColorScratchTexture);

void Main(
	in float2 UV : TEXCOORD0,
	out float4 OutColor : SV_Target0
	)
{
	half3 HDRSceneColor = tex2D(SceneColorScratchTexture,UV);
	// Find the largest color component
	half OutOfLDRangeFactor = max(HDRSceneColor.r, max(HDRSceneColor.g, HDRSceneColor.b));
	// Store how much the largest component is out of LDR range in alpha, which will be used by post process effects.
	OutColor = RETURN_COLOR(half4(HDRSceneColor.rgb, max(OutOfLDRangeFactor - 1.0f, 0.0f)));
}