// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

//  Copyright(c) 2016, Michal Skalsky
//  All rights reserved.
//
//  Redistribution and use in source and binary forms, with or without modification,
//  are permitted provided that the following conditions are met:
//
//  1. Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//
//  2. Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//
//  3. Neither the name of the copyright holder nor the names of its contributors
//     may be used to endorse or promote products derived from this software without
//     specific prior written permission.
//
//  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
//  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
//  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.IN NO EVENT
//  SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
//  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
//  OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
//  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
//  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
//  EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.



Shader "Hidden/BlitAdd" 
{
	Properties{ _MainTex("Texture", any) = "" {} }
	SubShader
	{
		Pass
		{
			ZTest Always Cull Off ZWrite Off
			Blend One Zero

			CGPROGRAM
	#pragma vertex vert
	#pragma fragment frag

	#include "UnityCG.cginc"

			sampler2D _MainTex;
			sampler2D _Source;
			uniform float4 _MainTex_ST;
			float4 _Source_TexelSize;

			struct appdata_t 
			{
				float4 vertex : POSITION;
				float2 texcoord : TEXCOORD0;
			};

			struct v2f 
			{
				float4 vertex : SV_POSITION;
				float2 texcoord : TEXCOORD0;
			};

			v2f vert(appdata_t v)
			{
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				o.texcoord = TRANSFORM_TEX(v.texcoord.xy, _MainTex);

				return o;
			}

			fixed4 frag(v2f i) : SV_Target
			{
				float4 main = tex2D(_MainTex, i.texcoord);

#if UNITY_UV_STARTS_AT_TOP
				if (_Source_TexelSize.y < 0)
					i.texcoord.y = 1 - i.texcoord.y;
#endif
				float4 source = tex2D(_Source, i.texcoord);

				source *= main.w;
				source.xyz += main.xyz;
				return source;
			}
			ENDCG
		}
	}
	Fallback Off
}