简单粗暴的技能冷却Shader

Shader "Unlit/NewUnlitShader"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _Angle("Angle", Range(0, 6.28318530718)) = 0
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100

        Blend SrcAlpha OneMinusSrcAlpha

        Pass
        {
            CGPROGRAM
#pragma vertex vert
#pragma fragment frag
            // make fog work
#pragma multi_compile_fog

#include "UnityCG.cginc"

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

            struct v2f
            {
float2 uv :
                TEXCOORD0;
                UNITY_FOG_COORDS(1)
float4 vertex :
                SV_POSITION;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;

            float _Angle;

            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                UNITY_TRANSFER_FOG(o,o.vertex);
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                // sample the texture
                fixed4 col = tex2D(_MainTex, i.uv);
                // apply fog
                UNITY_APPLY_FOG(i.fogCoord, col);

                float k = tan(_Angle);

                fixed x = i.uv.x - 0.5;
                fixed y = i.uv.y - 0.5;

                if (_Angle < UNITY_PI / 2)
                {
                    if (y < k * x || y > 0)
                        col.a = 0;
                }
                else if (_Angle < UNITY_PI)
                {
                    if (y > k * x || y > 0)
                        col.a = 0;
                }
                else if (_Angle < UNITY_PI / 2 * 3)
                {
                    if (y > k * x && y > 0)
                        col.a = 0;
                }
                else
                {
                    if (y < k * x && y > 0)
                        col.a = 0;
                }

                return col;
            }
            ENDCG
        }
    }
}