HairyMess is a R&D project exploring the capabilities of Compute Shaders within OpenGL.

Developed with openFrameworks, it uses the Position-Based-Dynamics algorithm (PBD) combined with a volumetric method
for hair simulation (Paper).
Inextensibility of hair strands can be computationally expensive because it takes a couple of iterations to satisfy the length constraint. This is where the Dynamic-Follow-the-Leader approach (DFTL) comes into play.

Algorithm steps:

Voxel grid:
–Clear voxel grid
–Fill voxel grid with density and velocity
–3D convolution (lowpass filter) of density and velocity
–Normalise voxel velocity and calculate density gradient

Strand Simulation:
–calculate velocity depending on friction and repulsion
–calculate new position
–calculate constraints
–collision detection

Checkout source code on Github.