Try this shader… It does windy grass… Just make a bunch of planes that are scattered randomly and intersects each other… Then put a grass texture on it.
Shader "Nature/Windy Grass" {
Properties {
_Color ("Main Color", Color) = (.5, .5, .5, 0)
_Color2 ("Fade Color", Color) = (1, .9, .8, 0)
_MainTex ("Base (RGB) Alpha (A)", 2D) = "white" {}
_Cutoff ("Base Alpha cutoff", Range (0,1)) = .5
}
SubShader {
Tags { "Queue" = "Transparent" }
BindChannels {
Bind "Color", color
Bind "Vertex", vertex
Bind "TexCoord", texcoord
}
Pass {
CGPROGRAM
// vertex Vertex
#include "waves.cginc" // Get in the helper wave functions
#include "UnityCG.cginc" // Get standard Unity constants
struct Appdata {
float4 vertex;
float3 normal;
float4 texcoord;
float4 color;
};
struct v2f {
float4 pos : POSITION;
float4 color : COLOR0;
float4 uv : TEXCOORD0;
float fog : FOGC;
};
uniform float4 _Color, _Color2;
v2f Vertex(Appdata v) {
v2f o;
const float4 _waveXSize = float4(0.012, 0.02, -0.06, 0.048) * 2;
const float4 _waveZSize = float4 (0.006, .02, -0.02, 0.1) * 2;
const float4 waveSpeed = float4 (0.3, .3, .08, .07) * 4;
float4 _waveXmove = _waveXSize * waveSpeed * 25;
float4 _waveZmove = _waveZSize * waveSpeed * 25;
// We model the wind as basic waves...
// Calculate the wind input to leaves from their vertex positions....
// for now, we transform them into world-space x/z positions...
// Later on, we should actually be able to do the whole calc's in post-projective space
float3 worldPos = mul ((float3x4)_Object2World, v.vertex);
// This is the input to the sinusiodal warp
float4 waves;
waves = worldPos.x * _waveXSize;
waves += worldPos.z * _waveZSize;
// Add in time to model them over time
waves += _Time.x * waveSpeed;
float4 s, c;
waves = frac (waves);
FastSinCos (waves, s,c);
float waveAmount = v.texcoord.y;
s *= waveAmount;
// Faste winds move the grass more than slow winds
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;
o.pos = mul(glstate.matrix.mvp, v.vertex);
o.fog = o.pos.w;
o.uv = v.texcoord;
o.color = lerp (_Color, _Color2, fade.xxxx);
return o;
}
ENDCG
AlphaTest Greater [_Cutoff]
Cull Off
SetTexture [_MainTex] { combine texture * primary double, texture}
}
}
SubShader {
Tags { "Queue" = "Transparent" }
Pass {
Blend SrcAlpha oneMinusSrcAlpha
AlphaTest Greater [_Cutoff]
Cull Off
color [_Color]
ZTest Less
SetTexture [_MainTex] { combine texture * primary DOUBLE, texture}
}
}
}
Bit stressed prior to GDC…