FX ThermalColors.shader

Shader "FX/ThermalColors"
{
    Properties
    {
        _Matcap("Matcap", 2D) = "white" {}
        _Mask("Mask", 2D) = "white" {}
        _Strength("Tinting Strength", Range(-2,2)) = 0.4
    }

    SubShader
    {
        Tags
        {
            "Queue" = "Geometry"
            "RenderType" = "Transparent"
            "ThermalVision" = "ThermalColors"
        }

        Pass
        {
            CGPROGRAM

            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                float4 uv : TEXCOORD0;
                float3 normal : NORMAL;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
                float2 cap : TEXCOORD2;
            };

            sampler2D _Mask, _Matcap;
            float _Strength;

            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;

                float3 vertexN = normalize(v.vertex);
                    // get vector perpendicular to both vertex and normal
                float3 viewCross = cross(vertexN, v.normal);

                o.cap = viewCross.xy * 0.5 + 0.5;
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                // Mask
                fixed4 m = tex2D(_Mask, i.uv);

                // take out masked area
                i.cap *= (1 - (m.g* _Strength));
                // color texture over cap
                fixed4 color = tex2D(_Matcap, i.cap);
                return color;

            }

            ENDCG
        }
    }
}