// Copyright 2006-2010 (C) - Frictional Games
//
// This file is part of HPL1 Engine
//
// For conditions of distribution and use, see copyright notice in LICENSE-shaders
//

///////////////////////////////////////////////////////
/// DIFFUSE SPECULAR LIGHTING VERTEX PROGRAM //////////
///////////////////////////////////////////////////////

vec4 position = gl_Vertex;
vec3 normal = gl_Normal;
vec2 uv = gl_MultiTexCoord0.xy;
vec4 tangent = gl_MultiTexCoord1;

out vec4 vLightColor;
out vec2 vUv;
out vec3 vLightDir;
out vec3 vHalfVec;

uniform mat4 worldViewProj;
uniform vec3 EyePos;
uniform vec3 LightPos;
uniform vec4 LightColor;
uniform vec3 LightDirMul;

void main()
{
	gl_Position = (worldViewProj * position);

	vUv = uv;

	vec3 lightDir = LightPos - position.xyz;
	vLightDir = lightDir * LightDirMul;

	//Calculate rotation for light to get it to tangent space.
	vec3 binormal = cross(normal,tangent.xyz)*tangent.w;
	mat3 rotation = transpose(mat3(tangent.xyz, binormal, normal));

	//Transform the lightdir
	vLightDir = (rotation * vLightDir);

	//Get the halfvector for the specular term
	vHalfVec = normalize(EyePos - position.xyz);
	//transform to tangent space
	vHalfVec = (rotation * vHalfVec);
	vHalfVec = normalize(vLightDir)+vHalfVec;

	vLightColor = clamp(LightColor, vec4(0.0), vec4(1.0));
}