Need to know the background knowledge:

Example of fluctuation:y=asin (ωx + φ)

φ:Determine the positional relationship or lateral movement distance between the waveform and the x-axis (left plus right minus)

ω:Determine the period (minimum positive period t=2Π/| ω |)

a:Determine the peak value (multiple of longitudinal stretching and compression)

The main calculation of the vertex shader:

1. Vertex position

2. Matrix conversion

Fragment shader

1. Texture Addressing

2. Light effect

_time represents the time period float4 (t/20, t, t * 2, t * 3)

shader "custom/wave" {
 properties {
 _maintex ("texture", 2d)="white" {} //Texture
 _arange ("amplitute", float)=1
 _frequency ("frequency", float)=2 //fluctuation frequency
 _speed ("speed", float)=0.5 //Control the speed of texture movement
 }
 subshader
 {
 pass
 {
 cgprogram
 #pragma vertex vert
 #pragma fragment frag
 #include "unitycg.cginc"
 struct appdata
 {
 float4 vertex:position;
 float2 uv:texcoord0;
 };
 struct v2f
 {
 float2 uv:texcoord0;
 float4 vertex:sv_position;
 };
 float _frequency;
 float _arange;
 float _speed;
 v2f vert (appdata v)
 {
 v2f o;
 float timer=_time.y * _speed;
 //Make a fluctuation before the change y=asin (ωx + φ)
 float waver=_arange * sin (timer + v.vertex.x * _frequency);
 v.vertex.y=v.vertex.y + waver;
 o.vertex=mul (unity_matrix_mvp, v.vertex);
 o.uv=v.uv ;;
 return o;
 }
 sampler2d _maintex;
 fixed4 frag (v2f i):sv_target
 {
 fixed4 col=tex2d (_maintex, i.uv);
 return col;
 }
 endcg
 }
 }
 fallback "diffuse"
}