//***
// MAIN PIXEL SHADER CODE
//***
float4 EnginePixelShader(EngineVertexToPixel input) : COLOR
{
  float4 diffuseTex = tex2D(DiffuseTextureSampler,input.texCoord);
  
  
  // The following is decal code that is not yet 
  // implemented as it causes other code to crash
  // please ignore for the time being
  /*float3 tanpos = mul(input.wPos,input.tangentMatrix);
  for(int i=0;i<8;i++)
  {
	if(decalActivated[i])
	if(sqrt(pow(input.wPos.x-decalPos[i].x,2)+pow(input.wPos.y-decalPos[i].y,2)+pow(input.wPos.z-decalPos[i].z,2))<decalRadius[i])
	{
		float3 tPos = mul(decalPos[i],input.tangentMatrix);
		float2 decalTexCoords = float2(tanpos.x-tPos.x,tanpos.y-tPos.y);
		decalTexCoords /= decalRadius[i] * 2;
		decalTexCoords.x += 0.5f;
		decalTexCoords.y += 0.5f;
		float4 diffuseDecal = tex2D(DiffuseTextureSampler,decalTexCoords);
		float OldW = diffuseTex.w;
		diffuseTex = (diffuseTex*(1-diffuseDecal.w))+(diffuseDecal*diffuseDecal.w);
		diffuseTex.w = OldW;
	}
  }*/
  
  
  
  float3 normalVector = float3(0,0,1);
  if(BumpMappingEnabled)
  {
	normalVector = (2.0 * tex2D(BumpTextureSampler, input.texCoord).rgb) - 1.0;
  
	normalVector = normalize(normalVector);
  }//else: normalVector=(0,0,1)
  
  float4 ambientCol = ambientColor;//default values for the output
  float4 diffuseCol = { 0, 0, 0, 0 };
  float4 specularCol = { 0, 0, 0, 0 };
  
  
  float3 viewVector = normalize(input.viewVec);
  
  {// Directional Light
        float3 dLightVector = normalize(mul(input.tangentMatrix, dLightDir));
	float bump = saturate(dot(normalVector, dLightVector));
	float3 reflect = normalize(2 * bump * normalVector - dLightVector);
	float spec = pow(saturate(dot(reflect, viewVector)), shininess);
	diffuseCol = saturate(dot(float3(0,0,1), dLightVector))*dLDiffuseColor;
	specularCol = bump*spec*dLSpecularColor;
  }

  // Point Lights
  for(int i=0;i<4;i+=1)
  {
   if(pLightOn[i])
   {
        float dist = sqrt( (float)pow(pLightPos[i].x-input.wPos.x,2)+(float)pow(pLightPos[i].y-input.wPos.y,2)+(float)pow(pLightPos[i].z-input.wPos.z,2) );
	if(dist <= pLightFar[i])
	{
		float fade=0.0f;
		if(dist<=pLightNear[i])
		  fade=1.0f;
		else
		  fade = 1.0f-((dist-pLightNear[i])/(pLightFar[i]-pLightNear[i]));
		float3 pLightDir = pLightPos[i]-input.wPos;
		float3 pLightVector = normalize(mul(input.tangentMatrix, pLightDir));
		diffuseCol += (saturate(dot(float3(0,0,1), pLightVector))*fade)*diffuseColor;
		if(SpecularEnabled)
		{
	          float bump = saturate(dot(normalVector, pLightVector));
	          float3 reflect = normalize(2 * bump * normalVector - pLightVector);
	          float spec = pow(saturate(dot(reflect, viewVector)), shininess);
		  specularCol += fade*saturate(bump*spec*specularColor);
		}
	}
   }
  }
  ambientCol.w = wAlpha;
  diffuseCol.w = wAlpha;
  specularCol.w = wAlpha;
  diffuseTex.w *= wAlpha;
  if(fullbright)
  {
	ambientCol = float4(1.0f,1.0f,1.0f,wAlpha);
	diffuseCol = float4(1.0f,1.0f,1.0f,wAlpha);
	specularCol = float4(1.0f,1.0f,1.0f,wAlpha);
  }
  return diffuseTex * saturate(ambientCol + diffuseCol + specularCol);
}







//***
//Relevant Variables
//***
bool fullbright;
float wAlpha=1;

float4x4 view : View;
float4x4 proj : Projection;
float4x4 world : World;
float4x4 wRot : Rotation;
float4x4 viewInverse : ViewInverse;

float3 pLightPos[16];
bool   pLightOn[16];
float3 pLightDiffuse[16];
float3 pLightSpecular[16];
float  pLightNear[16];
float  pLightFar[16];

bool BumpMappingEnabled = true;
bool SpecularEnabled = true;

float3 dLightDir = { 1, 1, 0 };
float4 dLDiffuseColor = { 0.0f, 0.0f, 0.0f, 1.0f };
float4 dLSpecularColor = { 0.0f, 0.0f, 0.0f, 1.0f };

float4 ambientColor = { 0.1f, 0.1f, 0.1f, 1.0f };
float4 diffuseColor = { 0.5f, 0.5f, 0.5f, 1.0f };
float4 specularColor = { 1.0f, 1.0f, 1.0f, 1.0f };
float shininess = 24.0f;







//***
//Main Technique
//***
technique maintechnique 
{
	pass pass0 
        {
		VertexShader = compile vs_3_0 EngineVertexShader();
		PixelShader  = compile ps_3_0 EnginePixelShader();
	}
}






//***
// Vertex shader output
// and Pixel shader input
//***
struct EngineVertexToPixel
{
    float4 pos : POSITION;
    float2 texCoord : TEXCOORD0;
    float3 wPos : TEXCOORD1;
    float3 viewVec : TEXCOORD2;
    float3x3 tangentMatrix : TEXCOORD3;
};







//***
// C# Code:
// updates the light in Effect engine
// called in update
//***
private void UpdateLightData(Effect engine)
{
    bool[] pLightOn = new bool[16];
    Vector3[] pLightPos = new Vector3[16], pLightDiffuse = new Vector3[16], pLightSpecular = new Vector3[16];
    float[] far = new float[16], near = new float[16];

    for (int i = 0; i < 16; i++)
    {
        pLightOn[i] = pLights[i].IsEnabled;
        pLightPos[i] = pLights[i].Position;
        near[i] = pLights[i].NearFalloff;
        far[i] = pLights[i].FarFalloff;
        pLightDiffuse[i] = new Vector3(pLights[i].Diffuse.X,pLights[i].Diffuse.Y,pLights[i].Diffuse.Z);
        pLightSpecular[i] = new Vector3(pLights[i].Specular.X,pLights[i].Specular.Y,pLights[i].Specular.Z);
    }
    engine.Parameters["pLightPos"].SetValue(pLightPos);
    engine.Parameters["pLightOn"].SetValue(pLightOn);
    engine.Parameters["pLightNear"].SetValue(near);
    engine.Parameters["pLightFar"].SetValue(far);
    engine.Parameters["pLightDiffuse"].SetValue(pLightDiffuse);
    engine.Parameters["pLightSpecular"].SetValue(pLightSpecular);
}