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

// STATIC: "LIGHTING_PREVIEW"			"0..1"	[PC]
// STATIC: "LIGHTING_PREVIEW"			"0..0"	[XBOX]

#include "shader_constant_register_map.h"
#include "common_fog_ps_fxc.h"

sampler BaseSampler1					: register( s1 );	// Base map 1
sampler BaseSampler2					: register( s2 );	// Base map 2
sampler BaseSampler3					: register( s3 );	// Base map 3
sampler BaseSampler4					: register( s4 );	// Base map 4
sampler LightmapSampler					: register( s5 );

const float4 g_FogParams				: register( PSREG_FOG_PARAMS );
const float4 g_EyePos_SpecExponent		: register( PSREG_EYEPOS_SPEC_EXPONENT );

#if ((defined(SHADER_MODEL_PS_2_B) || defined(SHADER_MODEL_PS_3_0)))

static const float3 cSpecularColor = float3( 1.0, 1.0, 1.0 );

#endif

#if LIGHTING_PREVIEW == 0

static const float3 g_cAmbientColor = float3( 0.0, 0.0, 0.0 );
const float4 g_TintValuesTimesLightmapScale	: register( PSREG_CONSTANT_02 );

#endif


struct PS_INPUT
{
	float4 vBaseTexCoord					: TEXCOORD0;	// xy = blend 1 coord, zw = lightmap cord
	float4 worldPos_projPosZ				: TEXCOORD1;
//	float3 vWorldNormal						: TEXCOORD2;
	float  flSpecPower						: TEXCOORD2;
	float4 vFowCoord						: TEXCOORD3;	// xy = fow, zw = blend4 coord
	float4 vAlphaBlend						: TEXCOORD4;
//	float3 worldVertToEyeVector				: TEXCOORD5;
	float4 vBlendCoords23					: TEXCOORD5;	// xy = blend2 coord, zw = blend3 coord
	float4 vColorBlend1						: COLOR0;
	float4 vColorBlend2						: COLOR1;
	float4 vColorBlend3						: TEXCOORD6;
	float4 vColorBlend4						: TEXCOORD7;
};


#if ( defined( SHADER_MODEL_PS_2_0 ) )

float ComputeMultiBlendFactor( const float BlendEnd, const float BlendAmount, inout float Remaining )
{
	float Result = 0.0;
   
	Result = smoothstep( 0.0, BlendEnd, BlendAmount );
	Result = clamp( Result, 0.0, Remaining );
	Remaining -= Result;
     
	return Result;
}

#else

sampler SpecSampler1					: register( s6 );	// Spec map 1
sampler SpecSampler2					: register( s7 );	// Spec map 2
sampler SpecSampler3					: register( s8 );	// Spec map 3
sampler SpecSampler4					: register( s9 );	// Spec map 4

float ComputeMultiBlendFactor( const float BlendStart, const float BlendEnd, const float BlendAmount, const float AlphaBlend, inout float Remaining )
{
	float Result = 0.0;
   
	if ( Remaining > 0.0 && BlendAmount > 0.0 )
	{
		float minb = max( 0.0, BlendEnd - BlendStart );
		float maxb = min( 1.0, BlendEnd + BlendStart );

		if ( minb != maxb )
		{
			Result = smoothstep( minb, maxb, BlendAmount );
		}
		else if ( BlendAmount >= minb )
		{
			Result = 1.0;
		}

	  	if ( BlendEnd < AlphaBlend )
	  	{
	  		float alpha = 2.0 - AlphaBlend - BlendEnd;
	  		Result *= clamp( alpha, 0.0, 1.0 );
   		}
	}
   
	Result = clamp( Result, 0.0, Remaining );
	Remaining -= Result;
   
	return Result;
}

#endif


float4 main( PS_INPUT i ) : COLOR
{
	float blendfactor1 = 0.0;
	float blendfactor2 = 0.0;
	float blendfactor3 = 0.0;
	float blendfactor4 = 0.0;
	float remaining = 1.0;

	float4	color1 = tex2D( BaseSampler1, i.vBaseTexCoord.xy ) * float4( i.vColorBlend1.rgb, 1.0 );
	float4	color2 = tex2D( BaseSampler2, i.vBlendCoords23.xy ) * float4( i.vColorBlend2.rgb, 1.0 );
	float4	color3 = tex2D( BaseSampler3, i.vBlendCoords23.zw ) * float4( i.vColorBlend3.rgb, 1.0 );
	float4	color4 = tex2D( BaseSampler4, i.vFowCoord.zw ) * float4( i.vColorBlend4.rgb, 1.0 );

#if ( defined( SHADER_MODEL_PS_2_0 ) )
   
	blendfactor1 = ComputeMultiBlendFactor( color1.a, i.vColorBlend1.a, remaining );
	blendfactor2 = ComputeMultiBlendFactor( color2.a, i.vColorBlend2.a, remaining );
	blendfactor3 = ComputeMultiBlendFactor( color3.a, i.vColorBlend3.a, remaining );
//	blendfactor4 = ComputeMultiBlendFactor( color4.a, i.vColorBlend4.a, remaining );
	blendfactor4 = remaining;

#else

	float4   spec1 = tex2D( SpecSampler1, i.vBaseTexCoord.xy ); 
	float4   spec2 = tex2D( SpecSampler2, i.vBlendCoords23.xy );
	float4   spec3 = tex2D( SpecSampler3, i.vBlendCoords23.zw );
	float4   spec4 = tex2D( SpecSampler4, i.vFowCoord.zw );

	blendfactor1 = ComputeMultiBlendFactor( spec1.a, color1.a, i.vColorBlend1.a, i.vAlphaBlend.r, remaining );
	blendfactor2 = ComputeMultiBlendFactor( spec2.a, color2.a, i.vColorBlend2.a, i.vAlphaBlend.g, remaining );
	blendfactor3 = ComputeMultiBlendFactor( spec3.a, color3.a, i.vColorBlend3.a, i.vAlphaBlend.b, remaining );
//	blendfactor4 = ComputeMultiBlendFactor( spec4.a, color4.a, i.vColorBlend4.a, i.vAlphaBlend.a, remaining );
	blendfactor4 = remaining;

#endif

	float3 vResult = ( color1.rgb * blendfactor1 ) + ( color2.rgb * blendfactor2 ) + ( color3.rgb * blendfactor3 ) + ( color4.rgb * blendfactor4 );

#if ( ( defined( SHADER_MODEL_PS_2_B ) || defined( SHADER_MODEL_PS_3_0 ) ) )

	float3 fSpecular = i.flSpecPower * cSpecularColor;
	float3 fSpecFinal = float3( 0.0, 0.0, 0.0 );
	if ( blendfactor1 > 0.0 )
	{
		fSpecFinal += spec1.rgb * i.vColorBlend1.rgb * blendfactor1;
	}
	if ( blendfactor2 > 0.0 )
	{
		fSpecFinal += spec2.rgb * i.vColorBlend2.rgb * blendfactor2;
	}
	if ( blendfactor3 > 0.0 )
	{
		fSpecFinal += spec3.rgb * i.vColorBlend3.rgb * blendfactor3;
	}
	if ( blendfactor4 > 0.0 )
	{
		fSpecFinal += spec4.rgb * i.vColorBlend4.rgb * blendfactor4;
	}
	
	vResult.rgb += fSpecFinal * fSpecular;

#endif


#if LIGHTING_PREVIEW == 0
	float3 lightmapColor = tex2D( LightmapSampler, i.vBaseTexCoord.zw );
	float3 diffuseLighting = lightmapColor * g_TintValuesTimesLightmapScale.rgb;
	diffuseLighting += g_cAmbientColor;
	
	vResult.rgb *= diffuseLighting;
#endif
	

	float fogFactor = CalcPixelFogFactor( PIXELFOGTYPE, g_FogParams, g_EyePos_SpecExponent.xyz, i.worldPos_projPosZ.xyz, i.worldPos_projPosZ.w );
	
	return FinalOutput( float4( vResult, fogFactor ), fogFactor, PIXELFOGTYPE, TONEMAP_SCALE_LINEAR );
}