Unity Shader - 板砖日志 - 简单的树、草 等植物的 随风飘扬 动画

目的

便于后续自己的 CTRL+C,V的面向复制、粘贴编程

思路

非常简单：可以使用 perlin noise，simple noise 或是其他的 noise 函数，又或是 noise tex 来提取顶点 xyz 的偏移

然后 vs 里便宜就好了，需要阴影跟随飘动的投影就加上 “LightMode”=“ShadowCaster” 的 pass

Script include cginc

#ifndef __WIND_COMMON_H__
#define __WIND_COMMON_H__

// jave.lin 2021/04/13

#include "UnityCG.cginc"

#if defined(_WIND_ON)

half	_WindSpeed;
half	_WindWavesScale;
half	_WindForce;
half4	_WindDir;
half	_MoveHeight;
half	_MoveHeightPow;

float3 mod3D289(float3 x) { return x - floor(x / 289.0) * 289.0; }

float4 mod3D289(float4 x) { return x - floor(x / 289.0) * 289.0; }

float4 permute(float4 x) { return mod3D289((x * 34.0 + 1.0) * x); }

float4 taylorInvSqrt(float4 r) { return 1.79284291400159 - r * 0.85373472095314; }

float snoise(float3 v)
{
	const float2 C = float2(1.0 / 6.0, 1.0 / 3.0);
	float3 i = floor(v + dot(v, C.yyy));
	float3 x0 = v - i + dot(i, C.xxx);
	float3 g = step(x0.yzx, x0.xyz);
	float3 l = 1.0 - g;
	float3 i1 = min(g.xyz, l.zxy);
	float3 i2 = max(g.xyz, l.zxy);
	float3 x1 = x0 - i1 + C.xxx;
	float3 x2 = x0 - i2 + C.yyy;
	float3 x3 = x0 - 0.5;
	i = mod3D289(i);
	float4 p = permute(permute(permute(i.z + float4(0.0, i1.z, i2.z, 1.0)) + i.y + float4(0.0, i1.y, i2.y, 1.0)) + i.x + float4(0.0, i1.x, i2.x, 1.0));
	float4 j = p - 49.0 * floor(p / 49.0);  // mod(p,7*7)
	float4 x_ = floor(j / 7.0);
	float4 y_ = floor(j - 7.0 * x_);  // mod(j,N)
	float4 x = (x_ * 2.0 + 0.5) / 7.0 - 1.0;
	float4 y = (y_ * 2.0 + 0.5) / 7.0 - 1.0;
	float4 h = 1.0 - abs(x) - abs(y);
	float4 b0 = float4(x.xy, y.xy);
	float4 b1 = float4(x.zw, y.zw);
	float4 s0 = floor(b0) * 2.0 + 1.0;
	float4 s1 = floor(b1) * 2.0 + 1.0;
	float4 sh = -step(h, 0.0);
	float4 a0 = b0.xzyw + s0.xzyw * sh.xxyy;
	float4 a1 = b1.xzyw + s1.xzyw * sh.zzww;
	float3 g0 = float3(a0.xy, h.x);
	float3 g1 = float3(a0.zw, h.y);
	float3 g2 = float3(a1.xy, h.z);
	float3 g3 = float3(a1.zw, h.w);
	float4 norm = taylorInvSqrt(float4(dot(g0, g0), dot(g1, g1), dot(g2, g2), dot(g3, g3)));
	g0 *= norm.x;
	g1 *= norm.y;
	g2 *= norm.z;
	g3 *= norm.w;
	float4 m = max(0.6 - float4(dot(x0, x0), dot(x1, x1), dot(x2, x2), dot(x3, x3)), 0.0);
	m = m * m;
	m = m * m;
	float4 px = float4(dot(x0, g0), dot(x1, g1), dot(x2, g2), dot(x3, g3));
	return 42.0 * dot(m, px);
}

void windNoiseHandle(inout float4 posOS, float modelY, float uv_v)
{
	if (_MoveHeight