MAMEWorld Forums - Programming - Re: MegaPlay Programming

Sega System C... why haven't you mentioned it early? just gave a little check, and wow, seems like a much cleaner approach, actually :P.

I may try to look up both in the driver code and in one of available ROMs in C2, to see how different the address map is or anything necessary. How much research has been done to it though? As in, does it have less "guess" work than the MegaPlay?

My only concern is now the sound driver for my game... I have worked a lot since my first post, and I got a very processor-intensive task for a game settings screen with a fine-timing visual distortion code running at Horizontal Interrupt (4th). The original first game of Sonic the Hedgehog had indeed a 68k-based sound driver (with the Z80 to handle the DAC), but not too long ago I replaced with a fully Z80-based version of it... and honestly.. I'm not really sure if 8.94Mhz would be enough to overcome the situation.
If I recall correctly, the 68k version of this sound driver may take up to 40% of the processing time. And both drivers handle the music tempos differently too. But I don't want lag!...

How differently does the V-Int work on this system? In STH, the "main" code section stays waiting for a flag that the V-Int should set in RAM, and only then follows with the rest of the execution (processing objects, the scroll engine..). V-Int is triggered at either 60 or 50 times per second (or more clearly, when it's about to work on a frame), and it requires a special flag to be set within VDP, and the SR register set to a specific value...

And finally, how different the color system is? Graphics keep being 4bpp but supporting more color tones? Or is it improved the "good" way and maybe give more color depth? segac2.cpp seems a bit confusing to me yet :P

I haven't gone much further with the MegaPlay yet; I don't know the Z80 instruction set too well yet, I have merely edited the description ROM with a hex editor so the strings look appealing to my game, and I only got to build my custom ROM just yesterday before going to sleep.
But, overall, the specially the C2, seems like a much better approach than the MegaPlay, but the lack of Z80 is my only drawback. I don't know if keeping everything at 68k side is going to make my game a bit slower, but everything else seems like great improvements. Anybody has a different opinion in this regard? What are your reasons?

Edited by CrazyMonkey (02/15/16 02:12 PM)