Shader "TENKOKU/sun_shader" {

Properties {
	_TintColor ("Tint Color", Color) = (0.5,0.5,0.5,0.5)
	_CoronaColor ("Corona Color", Color) = (0.5,0.5,0.5,0.5)
	_MainTex ("BRDF", 2D) = "white" {}
	_overBright ("OverBright", float) = 1.0
	_dispStrength ("Displace Amount", Range(0.0,10.0)) = 1.0
}

	
	SubShader {
		





		
		//Tags { "Queue"="Background" "RenderType"="Transparent"}
		//Blend One One
Tags { "Queue"="Background+1604"}
		Blend One One
		//Blend SrcAlpha OneMinusSrcAlpha
		Cull Front
		ZWrite Off
		
		Offset 1,995000
		//Offset 1,900000




		CGPROGRAM
		#pragma surface surf Ramp vertex:vert alpha
		#pragma target 3.0
		#pragma glsl
		
		

		sampler2D _MainTex;
		float4 _TintColor;
		float4 _CoronaColor;
		float _dispStrength;
		float _overBright;
		float4 _Tenkoku_overcastColor;
		float4 _TenkokuSunColor;
		float _Tenkoku_AmbientGI;
		float _Tenkoku_Ambient;
		float _Tenkoku_EclipseFactor;

		struct Input {
			float2 uv_MainTex;
			float4 color;
			float4 screenPos;
			float3 viewDir;
			float3 pos;
		};


		half4 LightingRamp (SurfaceOutput s, half3 lightDir, half3 viewDir, half atten){
			
			//lighting dot products
			s.Normal = normalize(s.Normal);
			float NdotL = dot(s.Normal, lightDir);
			float NdotE = dot(s.Normal, viewDir);
			
			//do diffuse wrap
			float diff = (NdotL * 0.5) + 0.5;
			float2 brdfUV = float2(NdotE * 1.0, diff);
			float3 BRDF = tex2D(_MainTex, brdfUV.xy).rgb;

			float4 c;
			c.rgb = s.Albedo;

			c.a = saturate((BRDF.b) * 1.0 * s.Alpha);
			



			c = saturate(c);
			c.a *= _overBright;
			c.a = lerp(1.0,c.a*dot(-viewDir,s.Normal),_CoronaColor.a);

			//lerp(fixed3(1.0,0.75,0.5),c.rgb,saturate(c.a));

			c.rgb *= c.a;

			c.a = s.Alpha;

//c.rgb = half3(1,1,1);//saturate(c.rgb);

c.rgb = _TintColor;//lerp(_TintColor.rgb,_CoronaColor.rgb, 0.0 );

half sSize = saturate(c.a - (saturate(_Tenkoku_overcastColor.a*3)));
sSize = sSize * saturate(lerp(-1.0,1.0,_Tenkoku_Ambient));

c.a = 0;

c.a += saturate(lerp(-0.5,1,dot(viewDir,-s.Normal))) * 0.05 * sSize * _Tenkoku_EclipseFactor;
c.a += saturate(lerp(-1,1,dot(viewDir,-s.Normal))) * 0.05 * sSize * _Tenkoku_EclipseFactor;
c.a += saturate(lerp(-2,1,dot(viewDir,-s.Normal))) * 0.1 * sSize * _Tenkoku_EclipseFactor;
c.a += saturate(lerp(-3,1,dot(viewDir,-s.Normal))) * 0.1 * sSize * _Tenkoku_EclipseFactor;
c.a += saturate(lerp(-6,1,dot(viewDir,-s.Normal))) * 0.1 * sSize * _Tenkoku_EclipseFactor;
c.a += saturate(lerp(-2,1,dot(viewDir,-s.Normal))) * sSize;



c.rgb = lerp(_CoronaColor.rgb, c.rgb * _TenkokuSunColor.rgb, c.a);
c.rgb = lerp(c.rgb,c.rgb * _TintColor.rgb,_TintColor.a);
c.rgb = (c.rgb + (_overBright * (lerp(0,1,dot(viewDir,-s.Normal))) * saturate(lerp(0.0,4.0,_Tenkoku_AmbientGI)) ));


c.a = saturate(c.a - (saturate(_Tenkoku_overcastColor.a*3)));
c.a = c.a * saturate(lerp(0.0,4.0,_Tenkoku_Ambient));


			return c;
			
		}
		
		void vert (inout appdata_full v, out Input o) {
			UNITY_INITIALIZE_OUTPUT(Input,o);
			float disp = 1.0;
			//v.vertex.xyz += (v.normal * (disp * (_dispStrength * 0.5)));
			v.vertex.xyz += (v.normal * (disp * (0.75)));
			o.color = v.color;
		}
		
		void surf (Input IN, inout SurfaceOutput o) {

			o.Albedo = _TenkokuSunColor.rgb;

			o.Alpha = 1.0;//saturate(lerp(1,-3,_Tenkoku_overcastColor.a));

			
			o.Gloss = 0.0;
			o.Specular = 0.0;
			o.Emission = o.Albedo*4;
		}
		ENDCG






	} 
}