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

Shader "Custom/ChromakeyTransparent" {
    Properties {
        _MainTex ("Base (RGB)", 2D) = "white" {}
        _TransparentColourKey ("Transparent Colour Key", Color) = (0,0,0,1)
        _TransparencyTolerance ("Transparency Tolerance", Float) = 0.01 
    }
    SubShader {
        Pass {
            Tags { "RenderType" = "Opaque" }
LOD 200
         
            CGPROGRAM
 
            #pragma vertex vert
            #pragma fragment frag
#include "UnityCG.cginc"
 
struct a2v
{
    float4 pos : POSITION;
    float2 uv : TEXCOORD0;
};
 
struct v2f
{
    float4 pos : SV_POSITION;
    float2 uv : TEXCOORD0;
};
 
v2f vert(a2v input)
{
    v2f output;
    output.pos = UnityObjectToClipPos (input.pos);
    output.uv = input.uv;
    return output;
}
         
sampler2D _MainTex;
float3 _TransparentColourKey;
float _TransparencyTolerance;
 
float4 frag(v2f input) : SV_Target
{
                // What is the colour that *would* be rendered here?
    float4 colour = tex2D(_MainTex, input.uv);
             
                // Calculate the different in each component from the chosen transparency colour
    float deltaR = abs(colour.r - _TransparentColourKey.r);
    float deltaG = abs(colour.g - _TransparentColourKey.g);
    float deltaB = abs(colour.b - _TransparentColourKey.b);
 
                // If colour is within tolerance, write a transparent pixel
    if (deltaR < _TransparencyTolerance && deltaG < _TransparencyTolerance && deltaB < _TransparencyTolerance)
    {
        return float4(0.0f, 0.0f, 0.0f, 0.0f);
    }
 
                // Otherwise, return the regular colour
    return colour;
}
            ENDCG
        }
    }
}