source-engine/materialsystem/stdshaders/floatcombine_ps2x.fxc

// STATIC: "CONVERT_TO_SRGB" "0..1"	[ps20b][= g_pHardwareConfig->NeedsShaderSRGBConversion()] [PC]
// STATIC: "CONVERT_TO_SRGB" "0..0"	[= 0] [XBOX]

#define HDRTYPE HDR_TYPE_FLOAT
#define HDRENABLED 1
#include "common_ps_fxc.h"

sampler FBSampler	: register( s0 );
sampler BloomSampler	: register( s1 );

const HALF4 settings : register( c0 );
						// x=sharpness,y=woodcut,z=bloom_amt,w=alpha sharpen factor
const HALF4 settings2 : register( c1 );						// x=bloom exp,y=vignette min scale z=vignette_power

struct PS_INPUT
{
	float2 texCoord				: TEXCOORD0;
	float2 ZeroTexCoord				: TEXCOORD1;
	float2 bloomTexCoord            : TEXCOORD2;
};


float4 main( PS_INPUT i ) : COLOR
{
	float4 fbSample = tex2D( FBSampler, i.texCoord );
	float4 bloom=tex2D(BloomSampler,i.bloomTexCoord);
	
	float2 xofs=2*(i.texCoord-float2(0.5,0.5));
	float dist=(1.0/2.0)*(xofs.x*xofs.x+xofs.y*xofs.y);
	float vig=pow(1-dist,settings2.z);

	fbSample=lerp(fbSample,bloom,(1-vig)*settings2.w);
	fbSample=lerp(bloom,fbSample,settings.x+settings.w*fbSample.a*settings2.w);

	float3 woodcut;
	if (bloom.x<fbSample.x)
		woodcut.x=1.0;
	else
		woodcut.x=0.0;
	if (bloom.y<fbSample.y)
		woodcut.y=1.0;
	else
		woodcut.y=0.0;
	if (bloom.z<fbSample.z)
		woodcut.z=1.0;
	else
		woodcut.z=0.0;
	fbSample.xyz=lerp(fbSample.xyz,woodcut.xyz,settings.y);

	bloom.xyz*=sqrt(LINEAR_LIGHT_SCALE);
	bloom.xyz=min(bloom.xyz,1.0);
	float lum=.3*bloom.x+.59*bloom.y+.11*bloom.z;
	lum=min(1.0,lum);

	float4 c_out=float4(cLightScale.xyz, 1) * fbSample + settings.z * pow(lum, settings2.x) * bloom;

	// calculate vignette (lens brightness falloff near edges)
	c_out.xyz*=max(settings2.y,vig);
	return FinalOutput( c_out, 0, PIXEL_FOG_TYPE_NONE, TONEMAP_SCALE_NONE );
}