Unlit-AlphaWithHoles.shader

// Unlit alpha-blended shader with MainColor
// - no lighting
// - no lightmap support
// - with holes

Shader "Unlit/Transparent With Holes" {
Properties {
	_MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
	_Radius ("Hole Radius", Float) = 50.0
	_CutOff1 ("Cut Off Ratio, ranges from [0, 1", Float) = 0.6
	_Hole1 ("Hole 1 World Pos, set .w to 1 to use", Vector) = (0, 0, 0, 0)
	_CutOff2 ("Cut Off Ratio, ranges from [0, 1", Float) = 0.6
	_Hole2 ("Hole 1 World Pos, set .w to 1 to use", Vector) = (0, 0, 0, 0)
	_CutOff3 ("Cut Off Ratio, ranges from [0, 1", Float) = 0.6
	_Hole3 ("Hole 1 World Pos, set .w to 1 to use", Vector) = (0, 0, 0, 0)
	_CutOff4 ("Cut Off Ratio, ranges from [0, 1", Float) = 0.6
	_Hole4 ("Hole 1 World Pos, set .w to 1 to use", Vector) = (0, 0, 0, 0)
	_CutOff5 ("Cut Off Ratio, ranges from [0, 1", Float) = 0.6
	_Hole5 ("Hole 1 World Pos, set .w to 1 to use", Vector) = (0, 0, 0, 0)
	_CutOff6 ("Cut Off Ratio, ranges from [0, 1", Float) = 0.6
	_Hole6 ("Hole 1 World Pos, set .w to 1 to use", Vector) = (0, 0, 0, 0)
	_CutOff7 ("Cut Off Ratio, ranges from [0, 1", Float) = 0.6
	_Hole7 ("Hole 1 World Pos, set .w to 1 to use", Vector) = (0, 0, 0, 0)
	_CutOff8 ("Cut Off Ratio, ranges from [0, 1", Float) = 0.6
	_Hole8 ("Hole 1 World Pos, set .w to 1 to use", Vector) = (0, 0, 0, 0)
}

SubShader {
	Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent"}
	LOD 1
	
	ZWrite Off
	Blend SrcAlpha OneMinusSrcAlpha 
	
	Pass {  
		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;
	float4 posWorld : TEXCOORD1;
};

sampler2D _MainTex;
float4 _MainTex_ST;
uniform float _Radius;

uniform float _CutOff1;
uniform float4 _Hole1;
uniform float _CutOff2;
uniform float4 _Hole2;
uniform float _CutOff3;
uniform float4 _Hole3;
uniform float _CutOff4;
uniform float4 _Hole4;
uniform float _CutOff5;
uniform float4 _Hole5;
uniform float _CutOff6;
uniform float4 _Hole6;
uniform float _CutOff7;
uniform float4 _Hole7;
uniform float _CutOff8;
uniform float4 _Hole8;

v2f vert (appdata_t v)
{
	v2f o;
	o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
	o.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
	o.posWorld = mul(_Object2World, v.vertex);
	return o;
}

void calc_alpha(in float4 posWorld, in float4 hole, in float cutoff, inout fixed4 col)
{
	float dist = distance(posWorld.xy, hole.xy);
	float cutoffDist = _Radius * cutoff;
	float calcAlpha;

	if (hole.w == 0 || dist > _Radius) calcAlpha = 1.0;
	else if (dist < cutoffDist) calcAlpha = 0.0;
	else calcAlpha = lerp(0, 1, (dist - cutoffDist)/(_Radius - cutoffDist));

	if (calcAlpha < col.a)
	{
		col.a = calcAlpha;
	}

	return;
}


fixed4 frag (v2f i) : COLOR
{
	fixed4 col = tex2D(_MainTex, i.texcoord);
	
	calc_alpha(i.posWorld, _Hole1, _CutOff1, col);
	calc_alpha(i.posWorld, _Hole2, _CutOff2, col);

	return col;
}
		ENDCG
	}
}

}