///////depth map
struct VS_OUT
{
	float4 hPosition	: POSITION;
	float4 Position		: TEXCOORD0;	
};

VS_OUT DepthVS(float4 position : POSITION,	
				uniform float4x4 worldViewProj)
{
  
  VS_OUT OUT;
 
  OUT.hPosition = mul(worldViewProj, position);
  OUT.Position = mul(worldViewProj, position);
  
  return OUT;
}

//for directional light
float4 DepthPS(VS_OUT IN ):COLOR
{
//return 1;
	float4 pos = (IN.Position / IN.Position.w);
	//pos = (pos +1.0 ) / 2.0;
	return float4(pos.z, pos.z * pos.z, 1, 1);	
}

VS_OUT DepthDistVS(float4 position : POSITION,	
				uniform float4x4 worldViewProj,
				uniform float4x4 worldView)
{
  
  VS_OUT OUT;
 
  OUT.hPosition = mul(worldViewProj, position);
  OUT.Position = mul(worldView, position);
  
  return OUT;
}

float4 DepthDistPS(VS_OUT IN,
					uniform float farPlane ):COLOR
{
	float dist = length(IN.Position.xyz) / farPlane;
	return float4(dist, dist * dist, 1, 1);	
	//return farPlane;
}

///////////////Shadow

struct VS_OUT_SHADOW
{
	float4 hPosition	: POSITION;
	float4 Position		: TEXCOORD0;
	float4 lPosition	: TEXCOORD1;
	float4 lVPosition	: TEXCOORD2;
};

VS_OUT_SHADOW depthShadowVS(float4 position : POSITION,	
							uniform float4x4 worldViewProj,
							uniform float4x4 world,
							uniform float4x4 lightViewProj)
{
  VS_OUT_SHADOW OUT;
  OUT.hPosition = mul(worldViewProj, position);
  float4 wPos = mul(world, position);
  OUT.lPosition = mul(lightViewProj, wPos);  
  OUT.lVPosition = 0;  
  OUT.Position = position;  
  return OUT;
}


float4 depthShadowPS(VS_OUT_SHADOW IN,
					uniform float4x4 lightViewProj,
					uniform sampler2D depthShadowMap : register(s0)
					):COLOR
{	
	float bias = 0.001;
	float4 light = float4(1,1,1,1);
	float4 shadow = float4(0.25,0.25,0.25,1);
	//float4 shadow = float4(0,0,0,1);
	
	if(IN.lPosition.z > 0.0)
	{
		float4 pos = (IN.lPosition / IN.lPosition.w);
		
		if(length(pos.xy)>1)		
			light = shadow;
		else
		{
			pos.xy = (pos.xy + 1.0) / 2.0;
			pos.y = 1.0 - pos.y;
			float4 storedDepth = tex2D(depthShadowMap, pos.xy);
	
			 
			float M1 = storedDepth.r;
			float M2 = storedDepth.g;
			float v2 = M2 - M1 * M1;
			float pmax = v2 / (v2 + pow(M1 - pos.z, 2));
			light = saturate(shadow + (1 - shadow) * pmax);
			
		}
		
	}
	else
		light = shadow;	
	
	return light;	
}



VS_OUT_SHADOW distShadowVS(float4 position : POSITION,	
							uniform float4x4 worldViewProj,
							uniform float4x4 world,
							uniform float4x4 lightView,
							uniform float4x4 lightViewProj)
{
  VS_OUT_SHADOW OUT;
  OUT.hPosition = mul(worldViewProj, position);
  float4 wPos = mul(world, position);
  OUT.lPosition = mul(lightViewProj, wPos);
  OUT.lVPosition = mul(lightView, wPos);  
  OUT.Position = position;  
  return OUT;
}


float4 distShadowPS(VS_OUT_SHADOW IN,
					uniform float4x4 lightViewProj,
					uniform float lightFarPlane,
					uniform sampler2D depthShadowMap : register(s0)
					):COLOR
{	
	float bias = 0.001;
	float epsilon = 0.001;
	float4 light = float4(1,1,1,1);
	float4 shadow = float4(0.85,0.85,0.85,1);
	
	if(IN.lPosition.z > 0.0)
	{
		float4 pos = (IN.lPosition / IN.lPosition.w);
		
		float d = length(pos.xy);
			
		light = saturate((1.0 - d)/0.05);
		
		if(d <= 1.0)
		{
			float dist = length(IN.lVPosition.xyz) / lightFarPlane;
			pos.xy = (pos.xy + 1.0) / 2.0;
			pos.y = 1.0 - pos.y;
			float4 storedDist = tex2D(depthShadowMap, pos.xy);
			dist -= bias;
			float lit_factor = light * (dist <= storedDist.r);	
    	 
			float M1 = storedDist.r;
			float M2 = storedDist.g;
			float v2 = min(max(M2 - M1 * M1, 0.0) +  epsilon, 1.0);
			float m_d = M1 - dist;
    		float pmax = v2 / (v2 + m_d * m_d);
						
    		// Adjust the light color based on the shadow attenuation
    		light = max(lit_factor, pmax);
    	
		}
		
	}
	else
		light = 0;	
	
	return shadow + (1 - shadow) * light;
}


/*
float4 depthShadowPS(VS_OUT_SHADOW IN,
					uniform float4x4 lightViewProj,
					uniform sampler2D depthShadowMap : register(s0)
					):COLOR
{	
	float bias = 0.0001;
	float4 light = float4(1,1,1,1);
	float4 shadow = float4(0.95,0.95,0.95,1);
	//float4 shadow = float4(0,0,0,1);
	
	if(IN.lPosition.z > 0.0)
	{
		float4 pos = (IN.lPosition / IN.lPosition.w);
		
		if(length(pos.xy)>1)		
			light = shadow;
		else
		{
			pos.xy = (pos.xy + 1.0) / 2.0;
			pos.y = 1.0 - pos.y;
			float4 storedDepth = tex2D(depthShadowMap, pos.xy);
	
			if(storedDepth.r + bias < pos.z)
			{
				light = shadow;
			}
		}
		
	}
	else
		light = shadow;
	
	
	return light;	
}
*/