﻿Shader "Oculus/Alpha Premultiply" {
    Properties{
        _MainTex("Base (RGB) Trans (A)", 2D) = "white" {}
    }
    SubShader{
        Tags{ "Queue" = "Transparent" "IgnoreProjector" = "True" "RenderType" = "Transparent" }

        Pass{
            ZWrite Off
            ColorMask RGBA

			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;
					half2 texcoord : TEXCOORD0;
				};

				sampler2D _MainTex;
				float4 _MainTex_ST;

				v2f vert (appdata_t v)
				{
					v2f o;
					o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
					o.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
					return o;
				}
				
				fixed4 frag (v2f i) : COLOR
				{
					fixed4 col = tex2D(_MainTex, i.texcoord);
					col.rgb *= col.a; // Premultiply alpha.
					//return fixed4(1,0,0,1);
					return col;
				}
			ENDCG
		}
    }
}
