C64 Games memories Mega Apocalpyse

In this video we look at Mega Apocalypse. How it uses bitmap mode, draws stars with a large lookup table, and plays sample sound effects using a timed non-maskable interrupt.
github.com/mar...

[@v-for-victory]

🎯 Key points for quick navigation:
00:00 *🕹️ Game Technical Details*
- Overview of Mega Apocalypse game details.
- Analysis of cyberload and tape turbo loader used.
- Exploration of obfuscated code before game execution.
02:01 *🧩 Code Execution Understanding*
- Examination of trapping code execution before game starts.
- Detailed look at memory loading and screen initialization.
- Compression and packing analysis of game data.
10:59 *🎮 Game Graphics Rendering*
- Analysis of bitmap display in the game.
- Identifying the rendering elements like sprites and bitmaps.
- Examination of the Starfield routine and memory access patterns.
25:14 *🌌 Starfield Plotting Routine Overview*
- Starfield plotting routine in the game explained,
- Individual stars are removed and drawn in new positions using a small number of instructions,
- The game's optimization of Starfield draw into a single buffered bitmap screen is highlighted.
30:17 *🔊 Sound Samples Playback Process Analysis*
- Examination of the nmi routine in the game for sample playback,
- Sample data layout and optimization for efficient memory usage discussed,
- Utilization of zero page registers for faster updates and efficient sample play explained.

[@Gansteeth]

I always admired the starfield in this game. Very interesting to see how it was done!

[@gfdggdfgdgf]

"Hey boss do you want me to cleanup and optimize the code?" "Ah don't bother, it's not like anyone is going to analyze the code 40 years from now"

[@MartinPiper6502]

lol

[@JamesGood]

Explaining the wonders of my youth, amazing. These modern tools, and your analysis, wonderful!

[@MartinPiper6502]

Glad you enjoyed it!

[@daniellomblock6216]

Fantastic video as usual, Martin! Always wondered how Simon made the starfield in this game. Same thing for games like Dropzone, Polar Bear in space and Wizball. Excellent description!!

[@rwxdesigns]

If you press C= key and Q together you can enter Insomniac mode, which just displays the starfield alone. Saves you having to clear the screen. 🙂

[@OlivierSimpleLife]

Thank so much for this deep dive into the starfield code. It's really impressive from a tech perspective, i would never have thought it's possible to do this using the bitmap mode. Mega Apocalypse is to me one of the most impressive game from a tech perspective (because of this starfield), the other one being "Bandits" and its super impressive soft sprites engine (even if i'm pretty sure its going for double buffering and however can't keep up with the amount of stuff which is displayed ... pretty sure it could be optimized also). Anyway great stuff as usual !

[@MartinPiper6502]

Thank you for the kind feedback and the membership. :) I think I'll look at Bandits next.

[@FREEZE64UK]

Fantastic video 👏 I love how much you were able to compress the file.

[@MartinPiper6502]

Thank you! Cheers! I'm rather surprised at how well it compressed too :)

[@GuybrushThreepwoodNZ]

Nice analysis of a cool effect! Thanks Martin

[@MartinPiper6502]

Cool user name :)

[@GuybrushThreepwoodNZ]

@@MartinPiper6502 I always wondered if a port of monkey island might be possible some how on the C64... After playing maniac mansion and Zak McKraken... Should be doable?

[@MartinPiper6502]

There was a point and click version, almost like a text plus graphics adventure, but I think it would be possible to have a more animated version. Like Prince of Persia. It might have to be on a large cartridge though.

[@JamesGood]

Thanks!

[@MartinPiper6502]

Wow thank you for the super thanks :)