#define MaxLights 3

float4x4 World;
float4x4 WorldViewProjection;

float DiffuseIntensity0;
float4 DiffuseColor0;
float3 LightDirection0;
float4 SpecularColor0;
float SpecularIntensity0;

float DiffuseIntensity1;
float4 DiffuseColor1;
float3 LightDirection1;
float4 SpecularColor1;
float SpecularIntensity1;

float DiffuseIntensity2;
float4 DiffuseColor2;
float3 LightDirection2;
float4 SpecularColor2;
float SpecularIntensity2;

sampler ColorMapSampler : register(s0);

struct VS_IN {
  float4 Pos 	  : POSITION;
  float2 Tex      : TEXCOORD0;
  float3 Norm   : NORMAL;
};

struct VS_OUT
{
    float4 oPos         	 : POSITION;
    float2 oTex              : TEXCOORD0;
    float3 oLight[MaxLights] : TEXCOORD1;
    float3 oNormal           : TEXCOORD4;
    float3 oCamView          : TEXCOORD5;
};

struct PS_OUT
{
    float4 Color : COLOR;
};

VS_OUT VS_AmbientDiffuse(VS_IN input, uniform float3 CameraPos)
{
    VS_OUT output /*= (VS_OUT)0*/;
    output.oPos = mul(WorldViewProjection,input.Pos);
    // Normalize the light directions
    
    output.oTex = input.Tex;
    output.oLight[0] = normalize(LightDirection0);
    output.oLight[1] = normalize(LightDirection1);
    output.oLight[2] = normalize(LightDirection2);
    output.oNormal = normalize(mul(World,float4(input.Norm,0.0f)));
    output.oCamView = CameraPos - mul(World, input.Pos);
    return output;
}


PS_OUT PS_AmbientDiffuse(VS_OUT input, uniform float4 AmbientColor, uniform float AmbientIntensity)
{
    PS_OUT output = (PS_OUT)0;
    
    // Get ambient light
    AmbientColor *= AmbientIntensity;
    // Get diffuse light
    float4 TotalDiffuseColor = float4(0,0,0,0);
    TotalDiffuseColor += (DiffuseIntensity0 * DiffuseColor0) * saturate(dot(input.oLight[0],input.oNormal));
    TotalDiffuseColor += (DiffuseIntensity2 * DiffuseColor1) * saturate(dot(input.oLight[1],input.oNormal));
    TotalDiffuseColor += (DiffuseIntensity1 * DiffuseColor2) * saturate(dot(input.oLight[2],input.oNormal));
    
    float3 Half0 = normalize(input.oLight[0] + normalize(input.oCamView));
    float3 Half1 = normalize(input.oLight[1] + normalize(input.oCamView));
    float3 Half2 = normalize(input.oLight[2] + normalize(input.oCamView));
    
    float specular0 = pow(saturate(dot(input.oNormal,Half0)),25);
    float specular1 = pow(saturate(dot(input.oNormal,Half1)),25);
    float specular2 = pow(saturate(dot(input.oNormal,Half2)),25);
    
    float4 texCol = tex2D(ColorMapSampler,input.oTex);
    texCol *= AmbientColor + TotalDiffuseColor;
    
    output.Color = texCol + ((SpecularColor0 * SpecularIntensity0) * specular0) + ((SpecularColor1 * SpecularIntensity1) * specular1) + ((SpecularColor2 * SpecularIntensity2) * specular2);
    return output;
}