"the vanishing of ethan carter" grass movement

Hi all,
I'm trying to create a grass shader with realistic wind movement like in this clip:

I can't get the movement to flow like that. Any help would be appreciated!

 

The base for something like that is this:

Code (csharp):

1.  
2. position.xz += 0.1 * sin(position.zx + time);
3.  

You will need add that it only affects the top and you might need to scale some things.

 

Thanks but that gives a very unnatural wave, the movement in the clip is much more complex. I have tried mixing a few sin waves with different frequencies but it looks... meh.

 

have a peek in TerrainEngine.cginc - you can find unity's sources here: http://unity3d.com/unity/download/archive

It contains many interesting sources you can pull apart such as:

Code (CSharp):

1.  
2. fixed4 TerrainWaveGrass (inout float4 vertex, float waveAmount, fixed4 color)
3. {
4.     float4 _waveXSize = float4(0.012, 0.02, 0.06, 0.024) * _WaveAndDistance.y;
5.     float4 _waveZSize = float4 (0.006, .02, 0.02, 0.05) * _WaveAndDistance.y;
6.     float4 waveSpeed = float4 (0.3, .5, .4, 1.2) * 4;
7.  
8.     float4 _waveXmove = float4(0.012, 0.02, -0.06, 0.048) * 2;
9.     float4 _waveZmove = float4 (0.006, .02, -0.02, 0.1);
10.  
11.     float4 waves;
12.     waves = vertex.x * _waveXSize;
13.     waves += vertex.z * _waveZSize;
14.  
15.     // Add in time to model them over time
16.     waves += _WaveAndDistance.x * waveSpeed;
17.  
18.     float4 s, c;
19.     waves = frac (waves);
20.     FastSinCos (waves, s,c);
21.  
22.     s = s * s;
23.    
24.     s = s * s;
25.  
26.     float lighting = dot (s, normalize (float4 (1,1,.4,.2))) * .7;
27.  
28.     s = s * waveAmount;
29.  
30.     float3 waveMove = float3 (0,0,0);
31.     waveMove.x = dot (s, _waveXmove);
32.     waveMove.z = dot (s, _waveZmove);
33.  
34.     vertex.xz -= waveMove.xz * _WaveAndDistance.z;
35.    
36.     // apply color animation
37.    
38.     // fix for dx11/etc warning
39.     fixed3 waveColor = lerp (fixed3(0.5,0.5,0.5), _WavingTint.rgb, fixed3(lighting,lighting,lighting));
40.    
41.     // Fade the grass out before detail distance.
42.     // Saturate because Radeon HD drivers on OS X 10.4.10 don't saturate vertex colors properly.
43.     float3 offset = vertex.xyz - _CameraPosition.xyz;
44.     color.a = saturate (2 * (_WaveAndDistance.w - dot (offset, offset)) * _CameraPosition.w);
45.    
46.     return fixed4(2 * waveColor * color.rgb, color.a);
47. }

You'll need to refer to the above include to get that code to run though.

 

@hippocoder Looks interesting, I will check it out. Thanks!