Unreal中的水

public float height;
[Range(0, 1f)]
public float sharp = 0.5f;//尖锐
[Range(0.5f, 10f)]
public float speed = 2f;//初相
[Range(1, 50)]
public int waveT;//周期
public Vector2 WaveDir = Vector2.left;
private Vector3[] baseVertices;

private void OnEnable()
{
        mesh = GetComponent<MeshFilter>().mesh;
        baseVertices = mesh.vertices;
}

void Update()
{
            Vector3[] vertices = this.mesh.vertices;
            for (int i = 0; i < vertices.Length; i++)
            {
                Vector3 vertice = this.baseVertices[i];
                float A = this.height;
                float w = (float)(2 * Math.PI / waveT);
                float Qi = sharp / w * A;
                float cosNum = Mathf.Cos(Time.time * speed + w * Vector2.Dot(WaveDir, new Vector2(vertices[i].x, vertices[i].z)));
                float sinNum = Mathf.Sin(Time.time * speed + w * Vector2.Dot(WaveDir, new Vector2(vertices[i].x, vertices[i].z)));
 
                vertice.x += Qi * A * WaveDir.x * cosNum;
                vertice.z += Qi * A * WaveDir.y * cosNum;
                vertice.y = sinNum * A;
 
                vertices[i] = vertice;
            }
            this.mesh.vertices = vertices;
            this.mesh.RecalculateNormals();//重新计算法线
}

Shader "Unlit/GerstnerWave"
{
    Properties
    {
		_Color("Color", Color) = (1,1,1,1)
		_WaveLength("WaveLength", float) = 4//水波长度，世界空间中波之间的波峰到波峰的距离
		_WaveAmplitude("WaveAmplitude", float) = 0.4//振幅，从水平面到波峰的高度
		_WindDirection("WindDirection", Range(0, 360)) = 70//风方向
		_WindSpeed("WindSpeed", float) = 0.4//风速系数
    }
    SubShader
    {
        Tags { "RenderType"="Transparent" "Queue"="Transparent" }
        LOD 100
		ZWrite On
		ZTest On
		Blend SrcAlpha OneMinusSrcAlpha
        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"
			#include "Lighting.cginc"

			fixed4 _Color;
			float _WaveLength;
			float _WaveAmplitude;
			float _WindDirection;
			float _WindSpeed;

			struct Wave {
				float3 vertex;
				float3 normal;
			};
			struct appdata
			{
				float4 vertex : POSITION;
			};

			struct v2f
			{
				float4 vertex : SV_POSITION;
				float3 normal : NORMAL;
			};

			Wave GerstnerWave(half2 pos, float waveCount, half waveLen, half amplitude, half direction, half windSpeed) {
				Wave waveOut;
				float time = _Time.y;
				direction = radians(direction);
				half2 D = normalize(half2(sin(direction), cos(direction)));//方向（D）：垂直于波峰传播的波阵面的水平矢量。
				half w = 6.28318 / waveLen;
				half L = waveLen;//波长（L）：世界空间中波之间的波峰到波峰的距离。
				half A = amplitude;//振幅（A）：从水平面到波峰的高度。
				half S = windSpeed * sqrt(9.8 * w);//速度（S）：波峰每秒向前移动的距离。
				half Q = 1 / (A * w * waveCount);//陡度 (Q) : 控制水波的陡度。

				half commonCalc = w * dot(D, pos) + time * S;
		
				half cosC = cos(commonCalc);
				half sinC = sin(commonCalc);
				waveOut.vertex.xz = Q * A * D.xy * cosC;
				waveOut.vertex.y = (A * sinC) / waveCount;
				half WA = w * A;
				waveOut.normal = half3(-(D.xy * WA * cosC), 1 - (Q * WA * sinC));
				waveOut.normal = waveOut.normal/waveCount;
				return waveOut;
			}
			Wave GenWave(float3 vertex) {
				half2 pos = vertex.xz;
				Wave waveOut;
				uint count = 4;
				for (uint i = 0; i < count; i++) {
					Wave wave = GerstnerWave(pos, count, _WaveLength, _WaveAmplitude, _WindDirection, _WindSpeed);
					waveOut.vertex += wave.vertex;
					waveOut.normal += wave.normal;
				}
				return waveOut;
			}

            v2f vert (appdata v)
            {
                v2f o;
				Wave wave = GenWave(v.vertex.xyz);
				v.vertex.xyz += wave.vertex;//叠加偏移
				o.vertex = UnityObjectToClipPos(v.vertex);
				o.normal = mul(wave.normal, (float3x3)unity_WorldToObject);
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
				//漫反射公式
				fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.rgb;
				fixed3 worldNormal = normalize(i.normal);
				fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz);
				fixed3 diffuse = _LightColor0.rgb * _Color.rgb * saturate(dot(worldNormal,worldLightDir));
				fixed3 color = ambient + diffuse;
                return fixed4(color, _Color.a);
            }
            ENDCG
        }
    }
}