🌬️ A tiny shader for wind

Wind is one of those effects that sells a scene instantly. Here's the smallest version I keep reaching for.

The idea

Offset each vertex by a sine wave, scaled by how high up the vertex sits — so the trunk stays put and the tips move most.

float sway = sin(time + worldPos.x) * heightMask;
position.xz += sway * strength;

Written out, the horizontal offset for a vertex is $o = A \sin(\omega t + \phi)\, m_h$, where $m_h$ is the height mask and $A$, $\omega$, $\phi$ are amplitude, frequency and phase:

$$o = A \sin(\omega t + \phi)\, m_h$$

Add a second wave at a different frequency and you get something that reads as natural motion rather than a metronome.