// Author：Blastom
// 这个Shader只用于Non-Directional烘培的物体，动态物体使用光照会不正常
// 支持GLES 2.0，包括Shader Level 2.0的机器；T4MBase
// 特别减少Vert传输到Frag的参数数目，因此无法使用surface。
// 升级Unity版本如果有算法改变，需要特殊处理。
Shader "Zhanyou/Scene/T3M 3 Textures" {
	Properties {
		_Splat0 ("Layer 1", 2D) = "white" {}
		_Splat1 ("Layer 2", 2D) = "white" {}
		_Splat2 ("Layer 3", 2D) = "white" {}
		[NoScaleOffset]_Control ("Control (RGBA)", 2D) = "white" {}
		_Emission("Emission", Float) = 1.0
	}
	CGINCLUDE
	#include "T3MBase.cginc"
	ENDCG

	SubShader {
		Tags {
			// 最后绘制，以最大限度剔除高消耗像素
			"Queue"="AlphaTest+1"
			"SplatCount" = "4"
			"RenderType" = "Opaque"
		}
		// Forward Base
		Pass
		{
			Name "FORWARD"
			Tags { "LightMode" = "ForwardBase" }

			CGPROGRAM
			#define UNITY_PASS_FORWARDBASE
			#pragma multi_compile_fwdbase
			#pragma multi_compile_fog
			#pragma vertex vert_Base
			#pragma fragment frag
            #pragma multi_compile __ PLAYER_HALO_ON

			fixed4 frag(v2f_Base i) : SV_TARGET
			{
				COLOR_FRAG;
				// 世界法线
				fixed3 worldNormal = fixed3(i.tSpace0.z, i.tSpace1.z, i.tSpace2.z);
				GET_UNITY_GI_COLOR;
				// 自发光功能
                c.rgb = giColor + c.rgb * _Emission;
				#if PLAYER_HALO_ON
				    c.rgb += _DirectionalLightColor * LightColorFromWorld(worldPos);
				#endif
				UNITY_APPLY_FOG(i.fogCoord, c);
				UNITY_OPAQUE_ALPHA(c.a);
				return c;
			}
			ENDCG
		}

		// Forward Add
		// 注：实际光照贴图只通过meta通道实现，Forward Add仅用于编辑器无光照贴图时预览
		// 简单处理，Forward Add也使用顶点计算光照和视野方向，真实光照参数
		// 该通道可以省去镜面高光等所需参数，因此按常规算法做
		Pass
		{
			Name "FORWARD_ADD"
			Tags { "LightMode" = "ForwardAdd" }
			ZWrite Off
			Blend One One
			CGPROGRAM
			#define UNITY_PASS_FORWARDADD
			#include "UnityCG.cginc"
			#include "Lighting.cginc"
			#include "AutoLight.cginc"
			#include "Gles2Helper.cginc"
			#pragma multi_compile_fwdadd
			#pragma multi_compile_fog
			#pragma skip_variants INSTANCING_ON
			#pragma vertex vert_Add
			#pragma fragment frag
			
			fixed4 frag(v2f_Add i) : SV_TARGET
			{
				#ifdef LIGHTMAP_ON
					fixed4 c = fixed4(0.0, 0.0, 0.0, 0.0);
				#else
					COLOR_FRAG;
					UNITY_LIGHT_ATTENUATION(atten, i, i.worldPos);
					half NtoL = max(0.0, i.lightDir.z);
					c.rgb = c.rgb * atten * _LightColor0.rgb * NtoL;
				#endif
				UNITY_APPLY_FOG(i.fogCoord, c);
				UNITY_OPAQUE_ALPHA(c.a);
				return c;
			}
			ENDCG
		}

		// Meta
		Pass
		{
			Name "Meta"
			Tags { "LightMode" = "Meta" }
			Cull Off

			CGPROGRAM
			#define UNITY_PASS_META
			#include "UnityCG.cginc"
			#include "UnityMetaPass.cginc"
			#pragma vertex vert
			#pragma fragment frag
			#pragma skip_variants FOG_LINEAR FOG_EXP FOG_EXP2
			#pragma skip_variants INSTANCING_ON
			
			struct v2f {
				float4 pos : SV_POSITION;
				float4 uv : TEXCOORD0;
			};

			v2f vert(appdata_full v) {
				v2f o;
				UNITY_INITIALIZE_OUTPUT(v2f, o);
				o.pos = UnityObjectToClipPos(v.vertex);
				o.uv = v.texcoord;
				return o;
			}

			fixed4 frag(v2f i) : SV_TARGET
			{
				COLOR_FRAG;
				UnityMetaInput metaIN;
				UNITY_INITIALIZE_OUTPUT(UnityMetaInput, metaIN);
				metaIN.Albedo = c.rgb;
				metaIN.Emission = c.rgb * _Emission;
				return UnityMetaFragment(metaIN);
			}
			ENDCG
		}
	}
	Fallback "Diffuse"
}