/*
===========================================================================

Doom 3 BFG Edition GPL Source Code
Copyright (C) 1993-2012 id Software LLC, a ZeniMax Media company. 
Copyright (C) 2013-2014 Robert Beckebans

This file is part of the Doom 3 BFG Edition GPL Source Code ("Doom 3 BFG Edition Source Code").  

Doom 3 BFG Edition Source Code is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Doom 3 BFG Edition Source Code is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Doom 3 BFG Edition Source Code.  If not, see <http://www.gnu.org/licenses/>.

In addition, the Doom 3 BFG Edition Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 BFG Edition Source Code.  If not, please request a copy in writing from id Software at the address below.

If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.

===========================================================================
*/

#include "renderprogs/global.inc"

uniform sampler2D	samp0 : register(s0); // texture 1 is the per-surface bump map
uniform sampler2D	samp1 : register(s1); // texture 2 is the light falloff texture
uniform sampler2D	samp2 : register(s2); // texture 3 is the light projection texture
uniform sampler2D	samp3 : register(s3); // texture 4 is the per-surface diffuse map
uniform sampler2D	samp4 : register(s4); // texture 5 is the per-surface specular map

struct PS_IN {
	half4 position	: VPOS;
	half4 texcoord0	: TEXCOORD0_centroid;
	half4 texcoord1	: TEXCOORD1_centroid;
	half4 texcoord2	: TEXCOORD2_centroid;
	half4 texcoord3	: TEXCOORD3_centroid;
	half4 texcoord4	: TEXCOORD4_centroid;
	half4 texcoord5	: TEXCOORD5_centroid;
	half4 texcoord6	: TEXCOORD6_centroid;
	half4 color		: COLOR0;
};

struct PS_OUT {
	half4 color : COLOR;
};

void main( PS_IN fragment, out PS_OUT result ) {
	half4 bumpMap =			tex2D( samp0, fragment.texcoord1.xy );
	half4 lightFalloff =	idtex2Dproj( samp1, fragment.texcoord2 );
	half4 lightProj	=		idtex2Dproj( samp2, fragment.texcoord3 );
	half4 YCoCG =			tex2D( samp3, fragment.texcoord4.xy );
	half4 specMap =			tex2D( samp4, fragment.texcoord5.xy );

	half3 lightVector = normalize( fragment.texcoord0.xyz );
	half3 diffuseMap = ConvertYCoCgToRGB( YCoCG );

	half3 localNormal;
	localNormal.xy = bumpMap.wy - 0.5;
	localNormal.z = sqrt( abs( dot( localNormal.xy, localNormal.xy ) - 0.25 ) );
	localNormal = normalize( localNormal );
	
	// RB: http://developer.valvesoftware.com/wiki/Half_Lambert
	float halfLdotN = dot3( localNormal, lightVector ) * 0.5 + 0.5;
	halfLdotN *= halfLdotN;
	
	// traditional very dark Lambert light model used in Doom 3
	//float ldotN = clamp( dot3( localNormal, lightVector ), 0.0, 1.0 );
	float ldotN = dot3( localNormal, lightVector );

	const half specularPower = 10.0f;
	half hDotN = dot3( normalize( fragment.texcoord6.xyz ), localNormal );
	// RB: added abs
	half3 specularContribution = _half3( pow( abs( hDotN ), specularPower ) );

	half3 diffuseColor = diffuseMap * rpDiffuseModifier.xyz;
	half3 specularColor = specMap.xyz * specularContribution * rpSpecularModifier.xyz;
	half3 lightColor = lightProj.xyz * lightFalloff.xyz;
	
	half rim =  1.0f - saturate( hDotN );
	half rimPower = 16.0f;
	half3 rimColor = diffuseColor * lightProj.xyz * lightFalloff.xyz * 1.0f * pow( rim, rimPower ) * fragment.color.rgb;// * halfLdotN;

	result.color.xyz = ( diffuseColor + specularColor ) * halfLdotN * lightColor * fragment.color.rgb;// + rimColor;
	result.color.w = 1.0;
}