struct fragment
{
	 // normalized screen position
	float4 pos: WPOS;
	float4 texCoord: TEXCOORD0; 
	float3 view: COLOR0;
};


struct pixel
{
	float4 color: COLOR0;
};



/** function for standard deferred shading
*/
float4 shade(fragment IN, 
			 uniform float4 color,
			 uniform float4 position,
			 uniform float3 normal,
			 uniform float amb)
{
	float4 lightDir = float4(0.8f, -1.0f, 0.7f, 0.0f);
	//float4 lightDir = float4(0.0f, 1.0f, 0.0f, 0.0f);
	float4 lightDir2 = float4(-0.5f, 0.5f, 0.4f, 0.0f);

	// global ambient
	const float4 ambient = 0.25f;

	// float3 L = normalize(lightPosition - position);
	float3 light = normalize(lightDir.xyz);
	float3 light2 = normalize(lightDir2.xyz);

	float diffuseLight = saturate(dot(normal, light));
	float diffuseLight2 = saturate(dot(normal, light2));

	float diffuse = diffuseLight + diffuseLight2;

	return (ambient + diffuse) * color * (1.0f - amb) + amb * color;
}



/** The mrt shader for standard rendering
*/
pixel main(fragment IN, 
		   uniform sampler2D colors,
		   uniform sampler2D positions,
		   uniform sampler2D normals	
		   )
{
	pixel OUT;

	float4 norm = tex2D(normals, IN.texCoord.xy);
	float4 color = tex2Dlod(colors, float4(IN.texCoord.xy, 0, 0));
	float4 position = tex2D(positions, IN.texCoord.xy);

	// an ambient color term
	float amb = norm.w;

	// expand normal
	float3 normal = normalize(norm.xyz);// * 2.0f - float4(1.0f));

	float4 col = shade(IN, color, position, normal, amb);
	
	//OUT.color = float4(1.0f);
	OUT.color = col;
	OUT.color.w = color.w;

	return OUT;
}

/** The mrt shader for standard rendering
*/
pixel main_shadow(fragment IN, 
				  uniform sampler2D colors,
				  uniform sampler2D positions,
				  uniform sampler2D normals,		   
				  uniform sampler2D shadowMap,
				  uniform float4x4 shadowMatrix,
				  uniform float maxDepth,
				  uniform float sampleWidth
				  )
{
	pixel OUT;

	float4 norm = tex2D(normals, IN.texCoord.xy);
	float4 color = tex2Dlod(colors, float4(IN.texCoord.xy, 0, 0));
	float4 position = tex2D(positions, IN.texCoord.xy);


	// an ambient color term
	float amb = norm.w;

	float3 normal = normalize(norm.xyz);
	float4 col = shade(IN, color, position, normal, amb);
	
	position *= maxDepth;
	position.w = 1.0f;
	
	float4 lightSpacePos = mul(shadowMatrix, position);

	float shadowDepth[9];

	float w = sampleWidth;

	// pcf sampling using 3 x 3 tab

	shadowDepth[0] = tex2D(shadowMap, lightSpacePos.xy).x;
	
	shadowDepth[1] = tex2D(shadowMap, lightSpacePos.xy + float2( w,  w)).x;
	shadowDepth[2] = tex2D(shadowMap, lightSpacePos.xy - float2( w, -w)).x;
	shadowDepth[3] = tex2D(shadowMap, lightSpacePos.xy - float2(-w, -w)).x;
	shadowDepth[4] = tex2D(shadowMap, lightSpacePos.xy - float2(-w,  w)).x;

	shadowDepth[5] = tex2D(shadowMap, lightSpacePos.xy - float2( w,  0)).x;
	shadowDepth[6] = tex2D(shadowMap, lightSpacePos.xy - float2( 0,  w)).x;
	shadowDepth[7] = tex2D(shadowMap, lightSpacePos.xy - float2(-w,  0)).x;
	shadowDepth[8] = tex2D(shadowMap, lightSpacePos.xy - float2( 0, -w)).x;

	OUT.color = col;
	
	float depth = lightSpacePos.z / lightSpacePos.w;

	float d = 0.0f;

	for (int i = 0; i < 9; ++ i)
	{
		d += step(shadowDepth[i], depth);
	}

	d /= 9.0f;
	
	/*if ((amb < 0.9) && // hack: prevent shadowing the sky	
		(lightSpacePos.z / lightSpacePos.w > shadowDepth))
	{
		OUT.color *= 0.1f;
	}*/
	
	if (amb < 0.9) // hack: prevent shadowing the sky	
	{
		const float x = 0.1f;
		OUT.color *= x + (1.0f - x) * (1.0f - d);
	}
	
	//OUT.color = lightSpacePos;//float4(lightSpacePos.z / lightSpacePos.w);
	//OUT.color = float4(shadowDepth);
	OUT.color.w = color.w;

	return OUT;
}