Balls(3)

NAME

Balls - MicroEmacs bouncing ball playground

SYNOPSIS

Balls

DESCRIPTION

A playground rather than a game - there is nothing to win. Balls fall, bounce off the walls and floor, roll, come to rest, and optionally bounce off each other. Up to 100 balls may be in the air at once.

Almost everything about the simulation can be changed while it is running: the strength and direction of gravity, how much speed a ball keeps when it bounces, whether balls collide with one another, and whether there is a bat to knock them about with. The current settings are shown along the status line, together with the frame rate.

Balls may be picked up and thrown by hand. Hold button 1 over a ball to grab it, move the pointer, and let go - the ball leaves with the speed of the throw. Button 3 drops a new ball wherever the pointer is.

The pointer may also be turned into a lump of gravity of its own with a, either pulling the balls towards it or pushing them away.

KEYS

The keys used to control Balls are:

? or h


Show or hide the key help.

space


Cycle the bat: off, across, upright, off.

n or x


Add or remove a ball.

s


Change the size of the next ball added: any size, tiny, small, medium, large.

r


Reset, back to the starting set of balls.

p


Pause.

.


Run a single frame, for watching a collision resolve.

a


The pointer as a lump of gravity: off, pull, push, off.

- or =


Weaken or strengthen that pull. + does the same as =.

g


Cycle gravity: normal, moon, none, upside down.

wheel


Trim gravity, one unit a click.

[ or ]


Less or more bounce.

c


Ball to ball collisions on or off.

button 1


Drag a ball to pick it up, let go to throw it.

button 3


Drop a new ball under the pointer.

q, esc or C-g


Quit.

NOTES

Balls is a macro defined in balls.emf.

The simulation runs in whatever room the window gives it and adjusts if the window is resized. Adding a great many balls with collisions turned on will lower the frame rate.

SEE ALSO

Games, Arkanoid(3).

Ref: Balls(3) File: m3mac111.3 Date: 2026/08/25

(c) Copyright JASSPA 2026