Shader "Custom/Wave" {
 Properties {
 
 _MainTex("Texture", 2D) = "white"{} //紋理
 _Arange("Amplitute", float) = 1
 _Frequency("Frequency", float) = 2//波動頻率
 _Speed("Speed",float) = 0.5//控制紋理移動的速度
 
 }
 
 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;
 //變化之前做一個波動 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"
}