Magic Serpent WHDLoad Pack

README
Short : HD Installer for Magic Serpent
Author: DJ Mike (djmike@crystalmike.com)
Version: 1.0
Type: game/patch
Requires: WHDLoad 18, 320k chip mem, 4k any mem

This patch applies to "Magic Serpent" © 1991 Software 2000.

Two versions are supported:
- Standalone disk release
- CDTV compilation release (with Cubulus)

REQUIREMENTS

- Original disk or compatible disk image
  (Cracks have not been tested and are not supported)
- Slave requires WHDLoad 18+
- Game requires 320k chip memory, plus 4k any memory
  (+ approx 700k other memory for preload option)

FEATURES

- Game loads fully from HD
- Uses real files, which can be compressed with Propack, CrunchMania or FImp
- Quit game at any time (default key F10), including on 68000 machines
- Control with either Joystick or Mouse in both versions
  * Set CUSTOM3=0 for Joystick (the default), or 1 for Mouse
- Press fire to start a 1-player game from title screen instead of using F1
- OS calls removed (no Kickstart ROM required)
- Filenames with '\' fixed for emulators, PC filesystems etc.
- Gfx corruption due to game writing copperlist during interrupt fixed
- Highscores loaded and saved to disk
- Disk drive accesses removed
- Missing blitter wait fixed
- CPU-dependent (empty DBF) loops fixed x15
- Trainer/other options added - set CUSTOM1 with any of the following:
  + 1 for infinite lives
  + 2 for infinite time
  + 4 to stop snake speeding up (including from items)
  + 8 to enable in-game cheat keys (screen flashes blue for on, red for off):
    * HELP to skip level
    * L to toggle infinite lives
    * T to toggle infinite time
    * S to toggle stopping snake speeding up
- Set CUSTOM2=1-60 to select starting level
- Color/New/Rom Icons included
- Source code included

HISTORY

Version 1.0 (2024-08-02)
- Initial release

WORDS FROM THE AUTHOR

Quite a fun game, this one! Although it has some issues on fast hardware and
emulators, the code was nice and easy to work through to see what was what.
A lot of work was needed to support both versions, as the changes between them
meant the offsets into the code for all the various fixes and features were
subtly different enough that each one had to be rechecked!

There were a LOT of empty loops that just don't work on any CPU higher than a
68000, and some file loading routines that were loading data in lots of little
bits that I've reworked to load all at once and relocate. But that means all
the files can now be packed if you wish to save disk space/preload memory.

The game also has a quirky race condition that can result in corrupt graphics,
due to the copperlist being rewritten during the vblank interrupt just as the
copper is already starting to execute it (and with no wait in the list to give
the CPU some time). This 'works' on real hardware but is not ideal - and most
definitely breaks WinUAE if cycle exact is switched off. A simple vpos wait in
the copperlist solves it.

When I got to supporting the CDTV version, I discovered it uses the mouse for
controlling the snake instead of the joystick, so I cross-supported both in
either version! You can specify which control you'd like with CUSTOM2=0 for
joystick (the default), or 1 for mouse (or just use the splash screen).
The default is joystick, even for CDTV, as it is less confusing that way.

Enjoy! :-)

--- DJ Mike (2nd August 2024)

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