unity3d 植物风力晃动材质 非地形风力

因为需要使用unity3d自带的风力，需要speedtree或者unity3d里面自己做树

这个比较麻烦，当然商城里也有一堆类似的插件，或者类似Custom Tree Importer都比较麻烦

不过我找了一个方便双面顶点动画材质对于小地方可以解急

Shader "Custom/Grass/GrassBending" {
Properties {
    _Color ("Main Color", Color) = (1,1,1,1)
    _MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
    _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
    _ShakeDisplacement ("Displacement", Range (0, 1.0)) = 1.0
    _ShakeTime ("Shake Time", Range (0, 1.0)) = 1.0
    _ShakeWindspeed ("Shake Windspeed", Range (0, 1.0)) = 1.0
    _ShakeBending ("Shake Bending", Range (0, 1.0)) = 1.0
}
SubShader {
    Tags {"Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="TransparentCutout"}
    LOD 200
    Cull Off
 
CGPROGRAM
#pragma target 3.0
#pragma surface surf Lambert alphatest:_Cutoff vertex:vert addshadow
sampler2D _MainTex;
fixed4 _Color;
float _ShakeDisplacement;
float _ShakeTime;
float _ShakeWindspeed;
float _ShakeBending;
float dist;
float _GrassAlpha;
struct Input {
    float2 uv_MainTex;
    float3 worldPos;
};
void FastSinCos (float4 val, out float4 s, out float4 c) {
    val = val * 6.408849 - 3.1415927;
    float4 r5 = val * val;
    float4 r6 = r5 * r5;
    float4 r7 = r6 * r5;
    float4 r8 = r6 * r5;
    float4 r1 = r5 * val;
    float4 r2 = r1 * r5;
    float4 r3 = r2 * r5;
    float4 sin7 = {1, -0.16161616, 0.0083333, -0.00019841} ;
    float4 cos8  = {-0.5, 0.041666666, -0.0013888889, 0.000024801587} ;
    s =  val + r1 * sin7.y + r2 * sin7.z + r3 * sin7.w;
    c = 1 + r5 * cos8.x + r6 * cos8.y + r7 * cos8.z + r8 * cos8.w;
}
void vert (inout appdata_full v) {
 
    float factor = (1 - _ShakeDisplacement -  v.color.r) * 0.5;
     
    const float _WindSpeed  = (_ShakeWindspeed  +  v.color.g );  
    const float _WaveScale = _ShakeDisplacement;
 
    const float4 _waveXSize = float4(0.048, 0.06, 0.24, 0.096);
    const float4 _waveZSize = float4 (0.024, .08, 0.08, 0.2);
    const float4 waveSpeed = float4 (1.2, 2, 1.6, 4.8);
    float4 _waveXmove = float4(0.024, 0.04, -0.12, 0.096);
    float4 _waveZmove = float4 (0.006, .02, -0.02, 0.1);
 
    float4 waves;
    waves = v.vertex.x * _waveXSize;
    waves += v.vertex.z * _waveZSize;
    waves += _Time.x * (1 - _ShakeTime * 2 - v.color.b ) * waveSpeed *_WindSpeed;
    float4 s, c;
    waves = frac (waves);
    FastSinCos (waves, s,c);
    float waveAmount = v.texcoord.y * (v.color.a + _ShakeBending);
    s *= waveAmount;
    s *= normalize (waveSpeed);
    s = s * s;
    float fade = dot (s, 1.3);
    s = s * s;
    float3 waveMove = float3 (0,0,0);
    waveMove.x = dot (s, _waveXmove);
    waveMove.z = dot (s, _waveZmove);
    v.vertex.xz -= mul ((float3x3)_World2Object, waveMove).xz;
 
}
void surf (Input IN, inout SurfaceOutput o) {
    fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color * _Color;
    o.Albedo = c.rgb;
    float dist = distance(_WorldSpaceCameraPos, IN.worldPos);
    dist = clamp(dist / 300, 0.4, 1.0);
    o.Alpha = c.a - dist - _GrassAlpha;
}
ENDCG
}
Fallback "Transparent/Cutout/VertexLit"
}

虽然只能一张贴图，但是也能控制alpha

这个也很好扩展

下面四个属性是控制风力大小的

 

原始shader网址

https://forum.unity.com/threads/custom-vegetation-mesh-wind-sway.305105/