Author Topic: Metal Slug port from Atari STE to MegaDrive / Genesis  (Read 1256 times)

Offline masteries

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Metal Slug port from Atari STE to MegaDrive / Genesis
« on: December 12, 2021, 01:59:27 pm »

Greetings mates,

I am Masteries, from Madrid, Spain

 Some years ago I acquired a never used, a brand new (non opened box), Atari STE computer.
 That is really a great machine, heavily underrated machine.
 Quickly I update it with 4 MB SIMM RAM modules... and I started on the search about how to program for it using C language...
 some time after I reached this state:
 This demonstration illustrates many of AGT libraries features, such fast sprite drawing routines, frame slipping, smooth scrolling and dualfield colouring technique, in order to increase the number of colours far beyond 16 usual ones.
 It is designed and running on a standard 8 MHz Atari STE with 4 MB RAM at 50 frames per second. Loading from diskette is granted, but hard drive or new sd card reader for extended joystick port is easier and recommended. Due to games developed on this way requires plenty disk space; this demo loads up to 3.1 MB of data, 512 KB of them are used for music and fx effects, other 512 KB are needed to store the extremely detailed NeoGeo quality level map graphics; the rest of them are for sprites; where many animations are not yet programmed, but these frames are being loaded.
 Sound is completely based on digital sound samples, mixed in a Real-Time manner; 3 voices at 12,5 KHz, arcade sound quality. The Yamaha YM2149 is not used in this example.
 Please, excuse me for the usage of english; I have little to no knowledge of Francais
 Original game code is not used here. Game code is programmed on C language using STE oriented libraries, the digital audio mixer is written on 68k assembly.

Now I am porting this Metal Slug conversion from Atari STE
to SEGA MegaDrive / Genesis console,
A video of the work in progress MegaDrive / Genesis version:

Mainly all the game engine is being ported from Atari STE to MegaDrive / Genesis.

 Audio playback is 100% based on digital samples, using a custom made sound driver that provides 3 channels mixed at 16 KHz. Samples are compressed, in order to save ROM space, and Real-Time decompressed using the Z80 processor.

 Currently, the same samples and graphics from the Atari STE version takes only 1 MB of MegaDrive / Genesis ROM space, while the STE version takes 3.6 MB

There is a high detailed background composed of up to 8600 tiles, and a parallax background.
Background uses up to 61 different colours.

Custom MegaDrive / Genesis tools are made to create map graphics data, and to provide colouring to the map tiles.

Many things are still pending to be ported to MegaDrive / Genesis,

Stay tuned!

Offline Berto

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Re: Metal Slug port from Atari STE to MegaDrive / Genesis
« Reply #1 on: December 12, 2021, 08:54:23 pm »
Hi Masteries, welcome to the forum.
That looks cool already, wish you best for your project.
I'll add it to the List for SEGA Homebrew Games.
Thank you for sharing.

Offline masteries

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Re: Metal Slug port from Atari STE to MegaDrive / Genesis
« Reply #2 on: December 16, 2021, 10:55:27 am »

​  Following the port of Metal Slug from Atari STE,
 This time, a brute force sprite test,
 in order to evaluate the limits of MegaDrive / Genesis hardware
 The scene of this video is insane from a gameplay perspective,

 But it illustrates the near arcade capabilities of MegaDrive / Genesis hardware