1.设置
sprite 动效的贴图与背景图设置成一致的

2.代码

Shader "Custom/SpriteWave2"{
    Properties{
        _Color ("Tint", Color) = (0, 0, 0, 1)
        _MainTex ("Texture", 2D) = "white" {}
    }

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

        Blend SrcAlpha OneMinusSrcAlpha

        ZWrite off
        Cull off

        Pass{

            CGPROGRAM

            #include "UnityCG.cginc"

            #pragma vertex vert
            #pragma fragment frag

            #define PI 3.1415926

            sampler2D _MainTex;
            fixed4 _Color;

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

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

            float func(float x){
                float xx = x * 0.5 * PI + _Time * 5.0;
                //xx = (1 - floor(xx)) * PI / 4 + PI / 4;
                //裁剪波谷
                float sx = abs(sin(xx));
                return sx / 20 + 0.9;
            }

            float plotFunc(float2 uv){
                float f = func(uv.x);
                return 1 - step(f,uv.y);
            }

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

            fixed4 frag(v2f i) : SV_TARGET{
                i.uv -= float2(-0.5,-0.5);

                float a = plotFunc(i.uv);
                fixed4 col = fixed4(0,0,a,0);
                if(a <= 0){
                    col.a = 0;
                }else{
                    col.a = 1;
                }
                return col;
            }

            ENDCG
        }
    }
}

3.效果: