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

// STATIC: "BASETEXTURE"				"0..1"

#include "common_vs_fxc.h"

const float4 cBumpTexCoordTransform[2]	:  register( SHADER_SPECIFIC_CONST_1 );
const float4 cBaseTextureTransform[2]	:  register( SHADER_SPECIFIC_CONST_3 );

struct VS_INPUT
{
	float4 vPos							: POSITION;
	float4 vNormal						: NORMAL;
	float4 vBaseTexCoord				: TEXCOORD0;
	float2 vLightmapTexCoord			: TEXCOORD1;
	float2 vLightmapTexCoordOffset		: TEXCOORD2;
	float3 vTangentS					: TANGENT;
	float3 vTangentT					: BINORMAL0;
};

struct VS_OUTPUT
{
	float4 vProjPos_POSITION		: POSITION;
	#if !defined( _X360 ) && !defined( SHADER_MODEL_VS_3_0 )
		float  fog						: FOG;
	#endif
	float4 vBumpTexCoordXY_vTexCoordXY : TEXCOORD0;
	float4 vPositionToCameraRayTs_projW	: TEXCOORD1;
	float4 vReflectXY_vRefractYX	: TEXCOORD2;
	float4 vProjPos					: TEXCOORD4;
	float3 worldPos					: TEXCOORD5;
	#if BASETEXTURE
		float4 lightmapTexCoord1And2		: TEXCOORD6;
		float4 lightmapTexCoord3			: TEXCOORD7;
	#endif
};

VS_OUTPUT main( const VS_INPUT v )
{
	VS_OUTPUT o = ( VS_OUTPUT )0;

	float3 vObjNormal;
	DecompressVertex_Normal( v.vNormal, vObjNormal );

	// Projected position
	float3 vWorldPos = mul4x3( v.vPos, cModel[0] );
	float4 vProjPos = mul( float4( vWorldPos, 1 ), cViewProj );
	
#ifdef _PS3
	// Account for OpenGL's flipped y coordinate and expanded z range [-1,1] instead of [0,1]
	vProjPos.y = -vProjPos.y;
	vProjPos.z = 2.0f * vProjPos.z - vProjPos.w;
#endif // _PS3

	o.vProjPos = o.vProjPos_POSITION = vProjPos;

	// Project tangent basis
	float2 vProjTangentS = mul( v.vTangentS, cViewProj ).xy;
	float2 vProjTangentT = mul( v.vTangentT, cViewProj ).xy;

	// Map projected position to the reflection texture
	float2 vReflectPos;
	vReflectPos.x = -vProjPos.x;
	vReflectPos.y = -vProjPos.y; // invert Y
	vReflectPos = ( vReflectPos + vProjPos.w ) * 0.5f;

	// Map projected position to the refraction texture
	float2 vRefractPos;
	vRefractPos.x = vProjPos.x;
	vRefractPos.y = -vProjPos.y; // invert Y
	vRefractPos = ( vRefractPos + vProjPos.w ) * 0.5f;

	// Reflection transform
	o.vReflectXY_vRefractYX = float4( vReflectPos.x, vReflectPos.y, vRefractPos.y, vRefractPos.x );
	o.vPositionToCameraRayTs_projW.w = vProjPos.w;

	// Compute fog based on the position
	o.worldPos = vWorldPos;

	#if !defined( _X360 ) && !defined( SHADER_MODEL_VS_3_0 )
		o.fog = CalcFixedFunctionFog( vWorldPos, FOGTYPE_RANGE );
	#endif

	// Eye vector
	float3 vPositionToCameraRayWs = cEyePos.xyz - vWorldPos.xyz;
	// Transform to the tangent space
	o.vPositionToCameraRayTs_projW.x = dot( vPositionToCameraRayWs.xyz, v.vTangentS.xyz );
	o.vPositionToCameraRayTs_projW.y = dot( vPositionToCameraRayWs.xyz, v.vTangentT.xyz );
	o.vPositionToCameraRayTs_projW.z = dot( vPositionToCameraRayWs.xyz, vObjNormal.xyz );

	// Tranform bump coordinates
	o.vBumpTexCoordXY_vTexCoordXY.x = dot( v.vBaseTexCoord, cBumpTexCoordTransform[0] );
	o.vBumpTexCoordXY_vTexCoordXY.y = dot( v.vBaseTexCoord, cBumpTexCoordTransform[1] );

	#if BASETEXTURE
		o.vBumpTexCoordXY_vTexCoordXY.z = dot( v.vBaseTexCoord, cBaseTextureTransform[0] );
		o.vBumpTexCoordXY_vTexCoordXY.w = dot( v.vBaseTexCoord, cBaseTextureTransform[1] );
	
		o.lightmapTexCoord1And2.xy = v.vLightmapTexCoord + v.vLightmapTexCoordOffset;
	
		float2 lightmapTexCoord2 = o.lightmapTexCoord1And2.xy + v.vLightmapTexCoordOffset;
		float2 lightmapTexCoord3 = lightmapTexCoord2 + v.vLightmapTexCoordOffset;
	
		// reversed component order
		o.lightmapTexCoord1And2.w = lightmapTexCoord2.x;
		o.lightmapTexCoord1And2.z = lightmapTexCoord2.y;
	
		o.lightmapTexCoord3.xy = lightmapTexCoord3;
	#else
		o.vBumpTexCoordXY_vTexCoordXY.z = 0.0f;
		o.vBumpTexCoordXY_vTexCoordXY.w = 0.0f;
	#endif

	return o;
}