水模拟

Shader "MyShader/flag"

{

    Properties

    {

        _MainTex ("Main Tex", 2D) = "white" {}

        _Color ("Color Tint", Color) = (1,1,1,1)

        _Magnitude ("Distortion Magnitude", Float) = 1

        _Frequency ("Distortion Frequency", Float) = 1

        _InvWaveLength ("Distortion Inverse Wave Length", Float) = 10

        _Speed ("Speed", Float) = 0.5

        _Diffuse ("Diffuse", Color) = (1.0,1.0,1.0,1.0)

    }

    SubShader

    {

        Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" "DisableBatching"="True"}

        Pass

        {

            Tags {"LightMode"="ForwardBase"}

            ZWrite Off

            Blend SrcAlpha OneMinusSrcAlpha

            Cull Off

            CGPROGRAM

            #pragma vertex vert

            #pragma fragment frag

            #include "Lighting.cginc"

            sampler2D _MainTex;

            float4 _MainTex_ST;

            fixed4 _Color;

            float _Magnitude;

            float _Frequency;

            float _InvWaveLength;

            float _Speed;

            fixed4 _Diffuse;

            struct a2v {

                float4 vertex : POSITION;

                float3 normal : NORMAL;

                float4 texcoord : TEXCOORD0;

            };

            struct v2f {

                float4 pos : SV_POSITION;

                float2 uv : TEXCOORD0;

                fixed3 worldNormal : TEXCOORD1;

            };

            float calPositionRate(float2 uv) {

                float t = 0;

                if(uv.x >= 0.5f)

                    t += (1 - uv.x);

                else

                    t += uv.x;

                if(uv.y >= 0.5f)

                    t += (1 - uv.y);

                else

                    t += uv.y;

                return t;

            }

            v2f vert(a2v v) {

                v2f o;

//                offset.x = sin(_Frequency * _Time.y + v.vertex.x * _InvWaveLength + v.vertex.y * _InvWaveLength + v.vertex.z * _InvWaveLength) * _Magnitude;

//                offset.x = sin(v.vertex.x * _InvWaveLength);

//                offset.x = sin((_Time.y * _Frequency + v.vertex.z * _InvWaveLength) * 5) * _Magnitude;

                o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);

//                o.uv += float2(0.0, _Time.y * _Speed);

                float4 offset;

                offset.xyw = float3(0.0,0.0,0.0);

                offset.z = 1 * sin((_Time.y * _Frequency + v.vertex.x * _InvWaveLength) * 5) * _Magnitude * clamp(sin(_Time.y * 0.2) , 0.25, 0.75);

                o.pos = UnityObjectToClipPos(v.vertex + offset);

                // cal v.normal

                float t = 1 * cos((_Time.y * _Frequency + v.vertex.x * _InvWaveLength) * 5) * _Magnitude * clamp(sin(_Time.y * 0.2) , 0.25, 0.75) * 5 * _InvWaveLength;

                float3 nor = normalize(cross(float4(v.vertex.x, 0, t,0), float4(0,1.0,0,0)));

//                if(nor.z < 0) {

//                    nor.z *= -1;

//                    nor.x *= -1;

//                    nor.y *= -1;

//                }

//                float3 nor3 = float3(0, 0, nor.z);

                o.worldNormal = mul(nor , (float3x3)unity_WorldToObject);

//                o.pos = UnityObjectToClipPos(v.vertex);

                return o;

            }

            fixed4 frag(v2f i) : SV_Target {

                fixed3 albedo = tex2D(_MainTex, i.uv).rgb * _Color.rgb;

                fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz * albedo;

                fixed3 worldNormal = normalize(i.worldNormal);

                fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz);

                fixed3 diffuse = _LightColor0.rgb * _Diffuse.rgb * pow(saturate(dot(worldNormal, worldLightDir)),8);;

                fixed3 color = ambient + diffuse;

                return fixed4(color, 1.0);

            }

            ENDCG

        }

    }

    FallBack "VertexLit"

}

1.表面网格的几何波动

2.网格上的法线扰动

水的高度由简单的周期波叠加而成，通过正弦函数叠加后得到的连续函数，描述水面上所有点的高度和方向。

对于2d水平面的任何点（x,y）副法线B和切线T分别是x和y方向的偏导数 由副法线和切线的叉积获取出该点的法线方向

遗留问题：1.我想在片段函数中计算法线 这样的话发现计算的就更精确 但是没有计算出来
2.在片段函数中我想弱化光照边缘的强度 使用了pow进行n次方操作 为什么整体强度变暗了