sampler2D Diffuse;
sampler2D Specular;
sampler2D Normal;
sampler2D Height;

struct PS_Input
{
	float2 TexCoord0 : TEXCOORD0;
	float3 WorldPosition : TEXCOORD1;
	float3 ModelNormal : TEXCOORD2;
	float3 ModelTangent : TEXCOORD3;
};

struct PS_Output
{
	float4 Colour : COLOR0;
};

struct Light
{
	float3 Position;
	float4 Colour;
	float Intensity;
};

float4x4 WorldMatrix;

float3 AmbientLightColour;
Light Lights[2];

float3 CameraPosition;
float SpecularPower;

float TextureDepth;

void main (in PS_Input input, out PS_Output output)
{
	float4 TextureDiffuse = tex2D(Diffuse, input.TexCoord0);
	float4 TextureSpecular = tex2D(Specular, input.TexCoord0);
	float4 TextureHeight = tex2D(Height, input.TexCoord0);
	
	float3 ModelNormal = normalize(input.ModelNormal);
	float3 ModelTangent = normalize(input.ModelTangent);
	float3 ModelBiTangent = cross( ModelNormal, ModelTangent );
	
	float3x3 InvTangentMatrix = float3x3(ModelTangent, ModelBiTangent, ModelNormal);
	
	float3 CameraDirection = normalize(CameraPosition - input.WorldPosition);
	
	float4x4 InvWorldMatrix = transpose(WorldMatrix);
	float3 CameraModelDirection = normalize( mul(CameraDirection, InvWorldMatrix));
	
	float3x3 TangentMatrix = transpose(InvTangentMatrix);
	float2 TextureOffsetDirection = mul(CameraModelDirection, TangentMatrix);
	
	float DepthInfo = TextureDepth * TextureHeight - 0.5f;
	
	float2 OffsetTextureCoord = input.TexCoord0 + DepthInfo * TextureOffsetDirection;
	
	float3 TextureNormal = 2.0f * tex2D(Normal, OffsetTextureCoord) - 1.0f;
	
	float3 WorldNormal = normalize( mul( mul( TextureNormal, InvTangentMatrix), WorldMatrix));
	
	float3 DiffuseColour = calcDiffuse(input.WorldPosition, WorldNormal);
	float3 SpecularColour = calcSpecular(input.WorldPosition, WorldNormal, CameraDirection);
	
	float4 TextureParallax = tex2D(Diffuse, OffsetTextureCoord);
	
	output.Colour.rgb =  TextureDiffuse * AmbientLightColour + TextureDiffuse * DiffuseColour * TextureParallax + TextureDiffuse * TextureSpecular * SpecularColour; //Make a colour specular map!
	output.Colour.a = 1.f;
}