Celebrating 30 Years of Color Robot Battle

Color Robot Battle is one of the earliest commercial programming games, published 30 years ago for the TRS-80 Color Computer by The Image Producers.

The game is played by writing programs to control a robot's movement, sensors and weapons. Programs are written in a hybrid of the BASIC / Logo programming languages. Two robots enter an arena with the survivor being declared the winner.

I asked the designer and programmer of Color Robot Battle what inspired the game:

“Well, the Apple II program did along with the feeling I could do it better. All of these were initially inspired by Core Wars, I believe. I did want to make the language complete enough to have quite a bit of control and flexibility over the robots.”

-- Glenn Sogge

“The robot controlling programming language was based on BASIC. Prior to working on CRB, I'd written a simple BASIC interpreter for the PDP-11, so it was a natural choice.”

-- Del Ogren

Color Robot Battle is a fantastic example of compact code. The game, compiler and full screen editor are all written in 6809 assembly language and somehow manage to fit on a 4K ROM.

Although the language of CRB only takes a few minutes to learn, a whole range of strategies are possible. There are four types of command available:

• movement: followed by a number. Movement commands are F(orwards), B(ackwards), L(eft), R(ight), H(alt), T(urn), D(irection).
• conditional: detect what the robot is facing. =(true) or #(false) followed by R(obot), W(all), M(issile), L(aser), S(omething - any direction), ?(random).
• flow control: C(all) or G(oto) a label. Labels are defined at the beginning of a line and terminated by a >.
• attack: XL to fire the laser or XM to fire a missile.

The program starts at the label START>. Multiple commands on one line are separated by a colon :. If a condition fails the rest of the line is skipped.

Here's a simple example that manages to win a few battles:

*SIGMA               ; robot name
START>               ; start here
F5                   ; move forward 5
=W:T1                ; if facing a wall, turn 45°                
=?:T1                ; randomly turn 45°
=R:XL                ; if facing a robot, fire laser
GSTART               ; repeat from start

Thanks to the simplicity of the language, CRB makes the perfect introduction to programming games. So, does anyone fancy a tournament? ;-)

• Color Robot Battle on the Programming Games Wiki
• Color Robot Battle: Adventures in Programming
• Tandy/TRS-80 Color Computer Robot Battle

A History of Programming Games 1961-1989

In a programming game players write a program to complete a specific task, usually to wipe out all opponents. The contest takes place between either programs in the memory of a virtual computer or robots in an arena.

Darwin

In August 1961, Douglas McIlroy, Robert Morris and Victor Vyssotsky invented Darwin and the programming game genre. Programs written using IBM 7090 machine code competed to destroy all opponents and be the most prolific replicator. An Umpire provided three functions to probe memory for an opponent, to claim memory or kill an opponent.

RobotWar

RobotWar was written in the 1970s by Silas Warner for the PLATO computer system and published commercially for the Apple II by MUSE Software in 1981. Programs written in a proprietary high level language control robots which battle to eliminate all opponents in a virtual arena. In the early 1980s a society was formed and an annual tournament organised by Computer Gaming World.

Color Robot Battle

The Image Producers released Color Robot Battle in 1981 for the TRS-80 Color Computer. The game was played by writing programs in a simple hybrid of BASIC and Logo to control a battle robot. Programs faced each other in a one-on-one battle with the last robot standing being declared winner.

Core War

Alexander Dewdney described Core War in the May 1984 issue of Scientific American, introducing programming games to a wide audience for the first time. Core War became popular overnight. A society was formed, a newsletter published and regular tournaments held. Core War is played between assembly languages programs in the memory of a virtual computer. Each program attempts to eradicate all opponents. Core War can be played by email at KOTH.org or KOTH@SAL.

DROID

Inspired by RobotWar, DROID was developed at Reichhold Chemicals as a teaching aid in December 1984. Programs to control robots are written in the D-code assembly language and attempt to exterminate all adversaries in the virtual arena. DROID can be played by Telnet on the Empire HPe3000 server.

CROBOTS

Tom Poindexter published CROBOTS as shareware in December 1985 after being inspired by RobotWar. A subset of C is used to control battle robots. As usual, the aim of the game is to destroy all opponents in a virtual arena. A king of the hill tournament is organised by Maurizio Camangi.

P-Robots

In 1988 David Malmberg released P-Robots, a robot battle game based on a subset of the Pascal programming language and inspired by CROBOTS. Later versions introduced a variety of optional extras for robots, teams and obstacles.

OMEGA

OMEGA is a programming game written by Stuart Marks and published by Origin Systems in 1989. The object of the game is to program a tank to defeat a series of increasingly more powerful enemies. Each opponent defeated unlocks a higher security clearance and increased budget.

Unfortunately there's very little information about some of these games online. Do you remember playing any of the above? Which is your favourite programming game and why?

RobotWar and the Army of Clones

Back in 1981 Silas Warner created a game for MUSE Software which would go on to spawn an entire army of clones. Silas is probably better know as the author of the legendary Castle Wolfenstein. However it was RobotWar which went on to inspire a whole new genre.

Silas developed RobotWar for the PLATO computer system and later ported it to the Apple II for release by MUSE. The game is set at a time in the distant future when war has been declared hazardous to human health. Wars still rage, but the combatants are robots programmed to battle to the death.

RobotWar is played by writing the control program for one of these battle robots. The program controls the movement, radar and gun of the robot. Here's one of the example robots:

;     ROBOT  'SCANNER'
; SEND RADAR PULSE AND FIRE IF AN
; ENEMY IS SPOTTED

SCAN
AIM + 7 TO AIM

CHECK
AIM TO RADAR
IF RADAR > 0 GOTO SCAN
0 - RADAR TO SHOT
GOTO CHECK

Scanner is a simple stationary warrior. The first instruction (at scan) turns the gun 7° clockwise. The next instruction (at check) lines up the radar with the gun. The radar returns a positive number if it detects nothing, otherwise it returns minus the distance to the opponent.

The next line jumps back to scan if the radar returns positive. Otherwise a shell is fired by the penultimate instruction and the next line jumps back to check.

RobotWar earned a strong following in the early 1980's. Computer Gaming World organised annual tournaments and a group of enthusiasts formed the Postal RobotWar Club of America.

RobotWar has inspired a huge number of clones, I'll just mention a select few here:

• CROBOTS by Tom Poindexter (1985) uses a subset of C
• P-Robots by David Malmberg (1988) uses a Pascal subset
• AT-Robots by Ed T Toten (1992) uses assembly language
• Robocode by Mathew Nelson (2001) uses Java

Robocode is currently the most active. More information is available on the RoboWiki.

Please let me know if you think I've missed an important robot programming game or one of historical note. Also I'd love to hear from you if you have any memories of the above.