# Snooker

> A full frame of snooker played in the browser in 3D, on a table built at the WPBSA's real
> dimensions, with a physical model of cue-ball spin and the complete rules of the game.

https://snooker.skillsafe.ai/

## What it is

An independent reimplementation of snooker — the 12-foot-table cue sport with 15 reds, six
colours that respot, and one of the most exhaustively codified rule sets in any sport. It is a
single self-contained web page: hand-written WebGL2, no libraries, no network requests after load,
no account, no data collection, and no AI model. It costs nothing and spends no credits.

## The rules

Built to the WPBSA "Official Rules of the Games of Snooker and English Billiards", Official World
Rules revised September 2024. Every rule is cited in the app by section, rule and paragraph.
Implemented: values and the order of play (S3 R1, R3); fouls and their values including the
four-point floor and the higher-of-the-two rule (S3 R11, R10(g)); free ball (S3 R12); snookered,
computed exactly from the extreme-edge tangent lines, including that a cushion cannot snooker you
(S2 R17); spotting a colour with the full precedence order and the all-spots-occupied case
(S3 R7(e)-(j)); the touching ball (S3 R8); the miss (S3 R14); and the endgame including the
re-spotted black (S2 R1, S3 R4). Not implemented: the stalemate re-rack, four-handed snooker and
six-red snooker.

## The physics

The player sets the aim, the strength, where the tip strikes the cue ball, and the elevation.
Everything else follows: a tip offset of b radii gives angular velocity (5/2)bv/R, so a ball
struck two fifths of a radius above centre rolls immediately; a sliding ball reaches rolling at
exactly 5/7 of its striking speed; friction at the ball-ball contact throws the object ball off
the line of centres by up to 3.4 degrees, which the aiming line compensates for; and a cushion
touches the ball 0.4 radii above its centre, which is why it puts topspin on a ball.

Ball-cloth and ball-cushion coefficients are measured on real snooker equipment (Mathavan, Jackson
and Parkin, 2009 and 2010). Ball-ball coefficients are Alciatore's published billiard figures; the
impact model reproduces his published table for the 90-degree rule to three decimal places.

## The pockets

No governing body publishes snooker pocket dimensions. The 2024 rulebook's entire pocket clause
says there shall be a pocket at each corner and one at the middle of each long side; earlier
editions referred to proprietary physical templates whose numbers have never been printed. This
app uses the WPBSA's 2005/6 rationalised template drawings: a 3 5/16 in corner opening with a
3.000 in jaw arc, a 3.906 in middle opening with a 3.125 in jaw arc. The middle pockets are wider
than the corners, and the jaws are pure arcs with no cut angle.

## Attribution

Snooker was created in 1875 by Sir Neville Chamberlain at Jabalpur, India. The rules are owned and
published by the World Professional Billiards and Snooker Association. This app is not affiliated
with, endorsed by or connected to the WPBSA, World Snooker Tour or any other body, and reproduces
none of their text, artwork or branding. Full sources: https://snooker.skillsafe.ai/CREDITS.txt