// Author: Blastom
// 仅用于摄像机拍摄UI面板的RenderTexture
// 该材质会向颜色Buffer中写入Alpha值，因此不会在没有背景时被剔除
Shader "Zhanyou/Particles/AlphaBlendAlphaWrite" 
{
Properties {
	_TintColor ("Tint Color", Color) = (0.5,0.5,0.5,0.5)
	_MainTex ("Particle Texture", 2D) = "white" {}
	//_InvFade ("Soft Particles Factor", Range(0.01,3.0)) = 1.0
    _ClipRect("Clip Rect", Vector) = (0,0,0,0)
    _UseMask("UseMask",Float) = 0
}

Category {
	Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" "PreviewType"="Plane" }
	Blend One OneMinusSrcAlpha
    //Blend One One//, One One

	//ColorMask RGB
	Cull Off
	Lighting Off
	ZWrite Off

	SubShader {
		Pass {
		
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			#pragma target 2.0
			#pragma multi_compile_fog
			
			#include "UnityCG.cginc"
            #include "UnityUI.cginc"


            float _UseMask;
            float4 _ClipRect;

			sampler2D _MainTex;
			fixed4 _TintColor;
			
			struct appdata_t {
				float4 vertex : POSITION;
				fixed4 color : COLOR;
				float2 texcoord : TEXCOORD0;
			};

			struct v2f {
				float4 vertex : SV_POSITION;
				fixed4 color : COLOR;
				float2 texcoord : TEXCOORD0;
                float3 vpos : TEXCOORD2;
				UNITY_FOG_COORDS(1)
			};
			
			float4 _MainTex_ST;

			v2f vert (appdata_t v)
			{
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
                o.vpos = mul(unity_ObjectToWorld, v.vertex).xyz;
				o.color = v.color;
				o.texcoord = TRANSFORM_TEX(v.texcoord,_MainTex);
				UNITY_TRANSFER_FOG(o,o.vertex);
				return o;
			}

			fixed4 frag (v2f i) : SV_Target
			{
				fixed4 col = i.color * _TintColor * tex2D(_MainTex, i.texcoord);
				col.a = clamp(col.a, 0, 1);
				UNITY_APPLY_FOG(i.fogCoord, col);
				col.rgb *= col.a;
                if (_UseMask >= 1)
                    col *= UnityGet2DClipping(i.vpos.xy, _ClipRect);

				return col;
			}
			ENDCG 
		}
	}	
}
}