Home of Defender of the World


The following products are covered here:

1. GS Invaders (freeware)
2mg format now available!

2. DOTW's Sprite Compiler (freeware)

3. Defender Of The World (freeware)
2mg format now available!

Released Freeware 

-- GS Invaders --

GS Invaders title screen

GS Invaders (Apple IIGS Version)
Copyright (C) 1993,94 by DOTW Productions
All rights are reserved

DOTW Productions presents GS Invaders:

A Space Invaders clone exclusively for the Apple IIGS. GS Invaders comes with everything the original arcade version of Space Invaders (Copyright (C) 1978 Atari Corp.) has and more! Play with keyboard/joystick, set number of laser shots from 1 to 3, set normal or zig-zag alien missiles for a more challenging game, enjoy the cool soundtracks and awesome sound effects, and marvel at the nice 16-colour graphics.

GS Invaders is released as freeware to the Apple IIGS community, a symbol of my labour of love for the Apple IIGS. :)

An actual game of GS Invaders

GS Invaders Credits:

David Ong Tat-Wee

Music/Sound Effects
Using Ian Schmidt's (irsman on #appleiigs) megatracker library MTLib routines

Title Screen Graphics
Joseph T. Lee (orionpax on #appleiigs)

Beta Testers
No one in particular: The game was too easy to write anyway. In fact, it was finished in less than a week. 8-)

Download GS Invaders 
Download GS Invaders (in 2mg format) 

-- DOTW's Sprite Compiler -- 

DOTW's Sprite Compiler (DSC)
Copyright (C) 1995 by DOTW Productions
All rights are reserved

DSC is a command-line based sprite compiler. It is executable under the GNO/ME shell (and maybe ORCA/M shell, though I've never tried that). DSC provides an alternative to Mr. Sprite (from those cool folks in France) and vsc (by Joseph T. Lee aka OrionPax). It was written to aid my software development as both Mr. Sprite and vsc have their own quirks and do not meet my needs. Mr. Sprite's desktop metaphor slows my productivity when I have to compile some 50+ sprites and it does not generate optimized codes. vsc accepts rIcons as input but I store my graphics in Apple Preferred Format ($c0) files. I do not have the means to convert them to rIcons nor do I really want to go through all that trouble. So DSC was born. :)

DSC Features:
- command-line interface for easy compilation via shell scripts
- accepts the very common Apple Preferred Format ($c0) graphics files generated by almost everything painting program
- Version 1.2 now supports both $c0 and screen dump $c1 files, and it autodetects them without requiring any external flags
- generates stack-based (PEA/etc) codes for solid block sprites without mask (cf. Mr. Sprite does not support this)
- supports register-caching for the above by using the X, Y and D registers for the 3 most commonly occuring pixel patterns (idea "stolen" from vsc, thanks OrionPax! :)
- Version 1.2 will use the A register for caching in block sprites only if it generates even more optimized code
- generates load/store direct-page (LDA/STA) codes for sprites with mask or "holes" in them. This may generate the same codes as Mr. Sprite, although DSC attempts to optimize them whenever possible
- supports register-caching for the above too, by using the X and Y registers for the 2 most commonly occuring pixel patterns (cf. Mr. Sprite does not support this as well)
- provides cycle-counting feature in verbose mode, so that you can know how long it takes to draw your sprite. Great for programmers writing timing critical codes in programs like demos
- outputs ORCA/M compatible 65816 assembly source codes. DSC also uses ENTRY to define a global label vs ANOP (used by Mr. Sprite) which only defines a local label, and DSC returns via RTL instead of RTS for more practical long subroutine calls, especially in a large >64k program

DSC has been put to practical use in my software development of the arcade game DOTW (see below). A 280x160 full scrolling background improves from 15 fps (via Mr. Sprite's codes) to 18-20 fps (via DSC's codes). Not a bad speed improvement, IMHO.

DOTW's Sprite Compiler Credits:

David Ong Tat-Wee

Download DOTW's Sprite Compiler 

-- Defender Of The World -- 

Defender Of The World title screen

Defender Of The World (Apple IIGS Version)
Copyright (C) 1994,95,96 by DOTW Productions
All rights are reserved

Beta release date: 16 Sept 1996
to celebrate the 10th birthday of the Apple IIGS
Actual release date: ??/??/????

DOTW Productions presents Defender Of The World:

Defender Of The World (DOTW) is a Nintendo/Sega style fast pace action-packed arcade shoot-'em-up exclusively for the Apple IIGS computer.

DOTW boasts of beautiful 16-colour graphics, large playing screen, full background with multi-layer parallax scrolling, plenty of large animated sprites, cool and rave soundtrack, digitized speech, mind-boggling sound effects, tonnes of weapon power-up and a ferocious non-stop action.

The animation never slows down, not even when there are lots of sprites on screen. Just a momentary lapse in concentration and your space battle cruiser will be blasted into oblivion by the fiercest alien fighters in any Apple IIGS arcade game.

Level 1 is currently completed. Work is now in progress on levels 2 and 3 simultaneously. There are no plans for DOTW to support Second Sight VGA graphics currently as DOTW's scrolling is too fast for Second Sight to handle. If this technological barrier can be overcome, DOTW may be upgraded to take advantage of Second Sight's graphics capbilities.

The following are some screen snapshots from DOTW levels 1, 2 and 3:

Defender penetrating asteriods field in level 1

Defender taking on a wave of alien fighters in level 1

Defender armed with magma, missiles and side shots, fighting a level 1 enemy boss

Defender cruising past a scrolling background of snowscape covered mountains in level 2, firing a shot at the dangerous ice dragon lurking ahead

Defender engaging a group of sine-wave alien fighters in the volcanic fire caves in level 3

Defender Of The World Credits:

David Ong Tat-Wee

Sprite Graphics/Background Design/Animation
David Ong Tat-Wee

Music/Sound Effects
Using Ian Schmidt's (irsman on #appleiigs) megatracker library MTLib routines 

Beta Testers (mostly on IRC #appleiigs)
Alvin Corey Tan (corey),
Dave Roberts (daver),
Ian Schmidt (irsman),
James Brookes (abaddon),
James Sanford (jsanford),
Lim Thye Chean (ltchean),
Murray Ong Chong Lay,
Mitchell Spector (appleReb),
Nathan Mates (gshacker),
Peter Handel (zelix),
Quek Meng Kiat (jie),
Richard Wifall (theJazz)

Programming Environment
Full 65816 native assembly language using ORCA/M compiler
running in GNO Multitasking Environment version 2.04
(currently comprises 22,000 lines of program code and 120,000 lines of compiled sprite code)

Download Defender Of The World (in .shk format) 
Download Defender Of The World (in .2mg format) 
Updated 1 June 2010 

(RC) Recovered From Original Site -- Updated May 2010