world_map.shader

Shader "Unlit/WorldMapHighlight"
{
    Properties{
		_Color ("Tint", Color) = (0, 0, 0, 1)
		_FullColor ("Full Color", Color) = (0, 0, 0, 1)
		_MainTex ("Texture", 2D) = "white" {}
		// _HighlightUV ("highlightUV", Vector) = (0, 0, 0, 1)
		_HighlightUV ("Highlight", Color) = (0, 0, 0, 1)
	}

	SubShader{
		Tags{
			"RenderType"="Transparent"
			"Queue"="Transparent"
		}

		Blend SrcAlpha OneMinusSrcAlpha

		ZWrite off
		Cull off

		Pass{

			CGPROGRAM

			#include "UnityCG.cginc"

			#pragma vertex vert
			#pragma fragment frag

			sampler2D _MainTex;
			float4 _MainTex_ST;

			fixed4 _Color;
			fixed4 _HighlightUV;
			fixed4 _FullColor;

			struct appdata{
				float4 vertex : POSITION;
				float2 uv : TEXCOORD0;
				fixed4 color : COLOR;
			};

			struct v2f{
				float4 position : SV_POSITION;
				float2 uv : TEXCOORD0;
				fixed4 color : COLOR;
			};

			v2f vert(appdata v){
				v2f o;
				o.position = UnityObjectToClipPos(v.vertex);
				o.uv = TRANSFORM_TEX(v.uv, _MainTex);
				o.color = v.color;
				return o;
			}

			fixed4 frag(v2f i) : SV_TARGET{
				fixed4 col = tex2D(_MainTex, i.uv);

				if (_HighlightUV.r == col.r && _HighlightUV.g == col.g  && _HighlightUV.b == col.b) {
					col *= _HighlightUV;
				} else {
					col *= _Color;
				}
				col *= i.color;

				return col;
			}

			ENDCG
		}
	}
}