// 使用Alpha Blend和Alpha Test混合处理
Shader "Zhanyou/Character/NPCDead" {
	Properties {
		_MainTex ("Base (RGB)", 2D) = "white" {}
		_Emission ("Emission", Range(0, 1)) = 0.2
		// 角色材质颜色，乘法运算
		_Color("Blend Color", Color) = (1, 1, 1, 1)
		// Emission叠加颜色，加法运算
		_AddColor("Additive Color", Color) = (0, 0, 0, 1)
		// 溶解贴图，RGB为颜色，A为溶解开始数值
		_DissolveTex ("Dissolve Tex", 2D) = "white" {}
		// 部分溶解的渐变区域值
		_DissolveFade ("Dissolve Fade", Range(0, 1)) = 0.1
		// 完全溶解的Alpha数值
		_DissolveEnd ("Dissolve End", Range(0, 1)) = 0.5
	}

	SubShader
	{
		Tags
		{
			"IgnoreProjector"="True"
	        "Queue"="AlphaTest+20"
			// 仍然认为这个是普通NPC的Type
	        "RenderType"="Opaque"
		}

		// 第一个通道为溶解未开始部分写入ZBuffer
		Pass
		{
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			#include "UnityCG.cginc"
			struct appdata_t
			{
				float4 vertex : POSITION;
				float2 texcoord : TEXCOORD0;
			};
			struct v2f
			{
				float4 vertex : SV_POSITION;
				float2 dissolveCoord : TEXCOORD0;
			};
			uniform sampler2D _DissolveTex;
			uniform half4 _DissolveTex_ST;
			uniform half _DissolveFade;
			uniform half _DissolveEnd;
			v2f vert (appdata_t v)
			{
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				o.dissolveCoord = TRANSFORM_TEX(v.texcoord, _DissolveTex);
				return o;
			}
			fixed4 frag (v2f i) : SV_Target
			{
				fixed4 dissolve = tex2D(_DissolveTex, i.dissolveCoord);
				clip(dissolve.a - _DissolveEnd - _DissolveFade);
				return 0;
			}
			ENDCG
		}
		// 第二个通道写入RGBA值
		Pass
		{
			Blend SrcAlpha OneMinusSrcAlpha
			// 注：部分NPC会挡住自己，暂时将渲染次序改高防止遮挡其他透明物体
			ZWrite Off
			Offset 0, 0.01
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			#pragma multi_compile_fog
			#include "NpcBase.cginc"
			struct v2f {
				float4 pos : SV_POSITION;
				float2 texcoord : TEXCOORD0;
				float2 dissolveCoord : TEXCOORD01;
				half rim : TEXCOORD2;
				UNITY_FOG_COORDS(3)
			};
			uniform sampler2D _DissolveTex;
			uniform half4 _DissolveTex_ST;
			uniform half _DissolveFade;
			uniform half _DissolveEnd;
			v2f vert (appdata_tan v)
			{
				v2f o;
				UNITY_INITIALIZE_OUTPUT(v2f, o);
				NPC_VERT_COMMON(o);
				o.dissolveCoord = TRANSFORM_TEX(v.texcoord, _DissolveTex);
				UNITY_TRANSFER_FOG(o, o.pos);
				return o;
			}
			fixed4 frag(v2f i) : SV_TARGET
			{
				fixed4 col;
				NPC_FRAG_COMMON(col);
				fixed4 dissolve = tex2D(_DissolveTex, i.dissolveCoord);
				if (dissolve.a <= _DissolveEnd + _DissolveFade)
				{
					col.a = max(0.0, (dissolve.a - _DissolveEnd) / _DissolveFade);
					col.rgb = lerp(lerp(dissolve.rgb, col.rgb, col.a), dissolve.rgb, col.a * col.a);
				}
				else
					UNITY_OPAQUE_ALPHA(col.a);
				UNITY_APPLY_FOG(i.fogCoord, col);
				return col;
			}
			ENDCG
		}
		// 其实没有用的投影通道，但是Unity貌似会用这个通道做屏幕深度运算，所以保留一个
		// Shadow Caster
		// ---- shadow caster pass:
		Pass {
			Name "ShadowCaster"
			Tags { "LightMode" = "ShadowCaster" }
			
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			#pragma multi_compile_shadowcaster
			#pragma skip_variants FOG_LINEAR FOG_EXP FOG_EXP2
			#include "HLSLSupport.cginc"
			#include "UnityShaderVariables.cginc"
			#define UNITY_PASS_SHADOWCASTER
			#include "UnityCG.cginc"
			#include "Lighting.cginc"
			half _Cutoff;

			uniform sampler2D _DissolveTex;
			uniform float4 _DissolveTex_ST;
			uniform half _DissolveFade;
			uniform half _DissolveEnd;
			struct v2f {
				V2F_SHADOW_CASTER;
				float2 uv : TEXCOORD1; // _MainTex
				float3 worldPos : TEXCOORD2;
			};
			v2f vert (appdata_full v) {
				v2f o;
				UNITY_TRANSFER_INSTANCE_ID(v,o);
				o.uv = TRANSFORM_TEX(v.texcoord, _DissolveTex);
				float3 worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
				fixed3 worldNormal = UnityObjectToWorldNormal(v.normal);
				o.worldPos = worldPos;
				TRANSFER_SHADOW_CASTER_NORMALOFFSET(o)
				return o;
			}
			fixed4 frag (v2f i) : SV_Target {
				fixed4 c = tex2D(_DissolveTex, i.uv);
				clip(c.a - _DissolveEnd - _DissolveFade);
				SHADOW_CASTER_FRAGMENT(i)
			}
			ENDCG
		}
	}
	Fallback "Zhanyou/Character/NPCAlpha"
}