一、Shader基础：4、顶点Shader，模拟水波

参考别人的代码，实现的一个水流波动效果。
原理是实时改变纹理贴图的坐标

// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "Custom/SinShader"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100

        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 : POSITION;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;

            v2f vert (appdata v)
            {
                v2f o;
                float dist = distance(v.vertex.xyz, float3(0, 0, 0));
                float h = sin(dist * 2 + _Time.z) / 5;//高度随时间做正弦波变化
                
                o.vertex = mul(unity_ObjectToWorld, v.vertex);
                o.vertex.y = h;
                o.vertex = mul(unity_WorldToObject, o.vertex);

                o.vertex = UnityObjectToClipPos(o.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);

                return o;
            }
            
            fixed4 frag (v2f i) : SV_Target
            {
                fixed4 col = tex2D(_MainTex, i.uv);
                return col;
            }
            ENDCG
        }
    }
}

或者改变一下写法也可以

// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "Custom/SinShader"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100

        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 : POSITION;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;

            v2f vert (appdata v)
            {
                v2f o;
                float dist = distance(v.vertex.xyz, float3(0, 0, 0));
                float h = sin(dist * 2 + _Time.z) / 5;
                
                //o.vertex = mul(unity_ObjectToWorld, v.vertex);
                o.vertex.x = v.vertex.x;
                o.vertex.w = v.vertex.w;
                o.vertex.z = v.vertex.z;
                o.vertex.y = h;
                //o.vertex = mul(unity_WorldToObject, o.vertex);

                o.vertex = UnityObjectToClipPos(o.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);

                return o;
            }
            
            fixed4 frag (v2f i) : SV_Target
            {
                fixed4 col = tex2D(_MainTex, i.uv);
                return col;
            }
            ENDCG
        }
    }
}