//-----------------------------------------------------------------------------
//           Name: Sky Shader
//         Author: Adrian (adoado)
//  	      For: Free Release. Based on the paper: http://es.geocities.com/kenchoweb/skydomes_en.pdf
//-----------------------------------------------------------------------------

float4x4 matWorldViewProj;
float4 vecSunDir;
float4 vecSunColor;

texture entSkin1;

float4 vecSkill1;

sampler SampSky = sampler_state
{
	texture = <entSkin1>;
	MinFilter = Linear;
	MagFilter = Linear;
	MipFilter = Linear;
};

struct VS_Input
{
    float3 position	: POSITION;
    float4 texcoord : TEXCOORD0;
    float4 normal : NORMAL;
};

struct VS_Output
{
    float4 position: POSITION;
    float4 texcoord: TEXCOORD0;
    float4 normal : TEXCOORD1;
};

struct PS_Output
{
	float4 color : COLOR;
};

VS_Output VertexShader_Pass0(VS_Input In)
{
    VS_Output Out;
    
	Out.position = mul(float4(In.position, 1),matWorldViewProj); 
	Out.texcoord = (In.texcoord);
	Out.normal = normalize(In.normal);
	return Out;
}     

PS_Output PixelShader_Pass0(VS_Output In)
{
   PS_Output Out;
	
	float OneMinute = 0.0444444444; //How many pixels correlate to one standard minute of time: 64/1440 (1440 = 24*60)
	float Location = 0.015625 * (OneMinute*vecSkill1.x); //Convert range [1][128] to range [0][1]: 0.015625 = 1/64
	
	float4 TexColor = tex2D(SampSky, float2(Location, In.texcoord.y)); //0.764
	
	Out.color = TexColor;
	Out.color *= vecSunColor;
	float light = 0.5 + 0.5 * dot(In.normal, vecSunDir);
	Out.color *= light;
	float4 sun = vecSunColor * 10*pow(light,20); //glowammount
	sun += vecSunColor * (dot(In.normal, vecSunDir)>0.7); //diameter of disk
	Out.color += sun;

	return Out;
}

//-----------------------------------------------------------------------------
// Technique (1 pass, PS/VS 2 compliant)
//-----------------------------------------------------------------------------

technique Technique0
{
    pass Pass0
    {
		VertexShader = compile vs_2_0 VertexShader_Pass0();
		PixelShader  = compile ps_2_0 PixelShader_Pass0();
    }
}