// Upgrade NOTE: replaced '_Object2World' with 'unity_ObjectToWorld'

///
/// -----  Allen 2018 -----
///	尝试使用rim texture和 specular texture
/// support lambert diffuse && blinn specular 
/// 支持Unity线性的雾
Shader "Am/FantacyQuanlity/livings_ui"
{
	Properties {
		//diffuse 贴图
		_MainTex("Base(RGB)", 2D) = "white"{}
		//边缘发光
		_RimLookup("Rim LUT(LookUp Table)", 2D) = "white" {}
		_SpecularLookup("Specular LUT(LookUp Table", 2D) = "white" {}

		_LightProbeDiffuseStrength("LightProbe Diff Strength", Vector) = (0.5, 0.5, 0.5)
		_RealtimeDiffuseStrength("Realtime Diff Strength", Vector) = (0.5, 0.5, 0.5)
		_RealtimeLightColor("RealTime Light Color", Color) = (0.5, 0.5, 0.5)
		_RealtimeLightDirection("RealTime Light Direction", Vector) = (0, -0.5, 0)
		//最终决定贴图的alpha
		_Alpha("alpha", Range(0, 1)) = 1
		_DiffuseStr("Diffuse Strength", Range(0, 2)) = 0.5
		_LightProbeRimStrength("LightProbe Rim Strength", float) = 0.5
		_LightProbeSpecularStrength("LightProbe Spec Strength", Range(0, 1)) = 0.5
		_RealtimeRimStrength("RealTime Rim Strength", float) = 0.5
		_RealtimeSpecularStrength("RealTime Specular Strength", Range(0, 1)) = 0.5
		
		_RimClamp("Rim Clamp", float) = 0.5
		_RimColor("Rim Color", Color) = (1.0, 1.0, 1.0, 1.0)
		_RimStr("Rim Strength", float) = 0.5
		_RimSpecularMaskStrength("Rim Specular Mask Strength", float) = 0.5
		_SpecularStr("Specular Strength", Range(0, 1)) = 0.5

		_FlowColor("Flow Color", Color) = (1,1,1,1)
		_FlowRange("Flow Range", Float) = 0.01
		_BrightScale("Light scale", Float) = 0.1
	}

	SubShader {
		Tags { "Queue"="Geometry" "RenderType"="Opaque" "LightMode"="ForwardBase" }
		LOD 100

		Pass {
			CGPROGRAM
			    #pragma shader_feature _SCAN_ON
				#pragma vertex vert
				#pragma fragment frag
				#pragma target 2.0
				#include "UnityCG.cginc"

				struct appdata_t 
				{
					float4 vertex : POSITION;
					float2 texcoord : TEXCOORD0;
					float3 normal : NORMAL;
				};
				
				struct v2f
				{
					float4 vertex : SV_POSITION;
					float4 texcoord : TEXCOORD0; //第0，1是UV0信息, 第2是雾的距离，第3是fresnel值
					float2 angle : TEXCOORD1;  //0 : lightprobe specular(UV) 1 : realtime light specular(UV)
					float3 probecolor : COLOR0;
					float3 color : COLOR1;
					float nr : TEXCOORD2;
				};

				sampler2D _MainTex;
				sampler2D _RimLookup;
				sampler2D _SpecularLookup;

				float4 _MainTex_ST;

				float3 _RealtimeLightColor;
				float3 _RealtimeLightDirection;
				float3 _RealtimeDiffuseStrength;
				float3 _LightProbeDiffuseStrength;
				
				float _Alpha;
				float _DiffuseStr;
				float _LightProbeRimStrength;
				float _LightProbeSpecularStrength;
				float _RealtimeRimStrength;
				float _RealtimeSpecularStrength;
				float _RimClamp;
				float3 _RimColor;
				float _RimStr;
				float _RimSpecularMaskStrength;
				float _SpecularStr;

				float4 _FlowColor;
				float _FlowRange;
				float _BrightScale;

				v2f vert (appdata_t v)
				{
					v2f o;
					UNITY_INITIALIZE_OUTPUT(v2f,o);

					o.vertex = UnityObjectToClipPos(v.vertex);
					// Transforms 2D UV by scale/bias property
					o.texcoord.xy = TRANSFORM_TEX(v.texcoord, _MainTex);
		
					//获得世界坐标中的normal
					float3 worldNormal = normalize(mul((float3x3)unity_ObjectToWorld, v.normal));
					float3 worldlook = normalize(_WorldSpaceCameraPos - mul(unity_ObjectToWorld, v.vertex).xyz);
					//for fresnel
					o.texcoord.w = dot(worldlook, worldNormal);
					//use lambert's law diffuse
					float3 rt_dir_lit = -_RealtimeLightDirection;
					float ndot = max(0, dot(worldNormal, rt_dir_lit));
					float3 color = _RealtimeLightColor * ndot * _RealtimeDiffuseStrength;
					o.color = color + fixed3(1, 1, 1) * _BrightScale * max(0, dot(v.normal, rt_dir_lit));
					return o;
				}


				fixed4 frag (v2f i) : SV_Target
				{
					fixed4 col = tex2D(_MainTex, i.texcoord.xy);
					col.rgb = col.rgb * _DiffuseStr;
					fixed fresnel = i.texcoord.w;
					fixed3 rtspec = _RealtimeLightColor * tex2D(_SpecularLookup, fixed2(i.angle.y, i.angle.y)) * _RealtimeSpecularStrength;
					fixed3 reflectionContribution = rtspec * col.a * _SpecularStr;
					col.rgb = col.rgb * i.color.rgb;
					col.rgb = col.rgb + reflectionContribution;
					fixed4 rimcolor = tex2D(_RimLookup, float2(fresnel, fresnel));
					col.rgb = col.rgb + _RimColor.rgb * rimcolor.rgb * _RimStr;
					col.a = _Alpha;
					return col;
				}

			ENDCG
		}

	}
}