Tech Art - umbrella fabric

We needed an umbrella for our VR puzzle game Kaisuo ( https://corphamy.artstation.com/projects/AN9V5 ), that supports opening and closing, and some basic physics-ish reactions.

The base open and close animation is a legacy asset from a year ago. It is very low poly, and is Maya cloth simulation baked into blend shapes. It is okay for just open and closing, but there was no physics reaction on the fabric when you wave it around, and breaks the immersion.

I revisited the old implementation a year later, using a vertex shader to rotate vertices according to the umbrella movement. The movement speed is sampled on a single point near the center of the umbrella. The direction of rotation is based on the position of the "petal" the vertex is on and the velocity the whole umbrella is moving. I used a bitmask texture to separate the petals, as vertices in one petal always wave towards the same direction.