Description

Perly Burly is a particle system driven by Perlin noise that produces images reminiscent of wood burl grain patterns -- or perhaps hair, water, mineral deposits, or other such things, depending on the palette used and scale of the grain patterns produced.

Applet

Perly Burly 300 x 300

Algorithm

The particle system acquires its velocity impulses from a field of layered Perlin noise generators. At each step of the particle's motion, it queries the noise field for a velocity vector from its current location. The particle's velocity is then adjusted and reduced by some amount of friction.

The particle's position is also squashed a bit each frame towards the center to 1) keep particles near the edge of the screen from flying off to nether regions, and 2) to produce a more interesting core of the pattern (as if a burl or tree limb had been cross-sectioned).

The various forces (velocity, friction and squashing) are all randomly assigned, but are kept within relatively narrow ranges. Too much friction and not enough velocity leads to lazy particles, too much squash would lead to to central collapse, et cetera. So the ranges were carefully chosen to balance each other out and maintain the desired activity in the system.

Each particle is randomly assigned a color that gradually fades in as the particle moves along its path. (this fading plus the squashing is responsible for the vignetting effect at the edges) Once completely visible, the particle is then reset to a new location and color and continues as before.

Gallery

Burls:

Walnut 600x600 127k Poplar 600x600 126k Golden Oak 600x600 123k

Maple 600x600 120k Teak 600x600 133k Redwood 600x600 112k

Weathered Cedar 600x600 105k Mahogony 600x600 122k Cherry 600x600 136k

Miscellaneous:

Water 600x600 152k Alien Fur 600x600 123k Plasma 600x600 126k

High Resolution Wallpaper 1600x1200 587k