I'm currently having problems emulating audio for Comix Zone. Samples (DAC) playback appears to be really slow and the music is all kinds of off tempo. Does anyone know what drives the music for this game as far as timings/interrupts etc?
cheers,
Steve.
Search found 29 matches
- Mon Aug 23, 2010 2:16 am
- Forum: Megadrive/Genesis
- Topic: Audio problems with Comix Zone
- Replies: 1
- Views: 2392
- Thu Apr 08, 2010 4:13 am
- Forum: Video Display Processor
- Topic: How does Sonic2 handle sprites for interlace mode?
- Replies: 7
- Views: 9828
- Wed Apr 07, 2010 8:13 pm
- Forum: Video Display Processor
- Topic: How does Sonic2 handle sprites for interlace mode?
- Replies: 7
- Views: 9828
Thanks for the help guys. Since I only have to display either the top or bottom half of the interlace display (stretched to full screen), my solution was to parse and save off the sprite table at the beginning of the frame for top half, or at end of line 112 for the bottom half. I then render this s...
- Wed Apr 07, 2010 5:05 am
- Forum: Video Display Processor
- Topic: How does Sonic2 handle sprites for interlace mode?
- Replies: 7
- Views: 9828
Re: How does Sonic2 handle sprites for interlace mode?
With this method for Sonic2 I'm only able to see sprites if I subtract 224 from their y position - and I mainly see the sprites of the bottom half of the interlace display (Tails' screen). For the normal and single density interlace modes bits 8-0 of the sprite Y coordinate are used. In the double ...
- Wed Apr 07, 2010 4:38 am
- Forum: Video Display Processor
- Topic: How does Sonic2 handle sprites for interlace mode?
- Replies: 7
- Views: 9828
How does Sonic2 handle sprites for interlace mode?
I'm currently working on Sonic2 double resolution interlace mode emulation, and I'm seeing some weirdness with sprite rendering. My current emulation does not perform per scan line sprite table query rendering, but rather at the end of the frame just parses the current sprite table and renders each ...
- Fri Apr 03, 2009 11:33 pm
- Forum: Megadrive/Genesis
- Topic: What are the 68K/Z80 clock spes for NTSC v PAL machines?
- Replies: 9
- Views: 7563
- Fri Apr 03, 2009 8:55 pm
- Forum: Megadrive/Genesis
- Topic: What are the 68K/Z80 clock spes for NTSC v PAL machines?
- Replies: 9
- Views: 7563
Ok - I think I'm going crazy. Extra lines or no extra lines 50hz is 50hz. So if a game ROM is for both NTSC and PAL, sample play back for PAL will be lower pitched unless the z80 code compensates for it. I might be missing reporting my genesis emulator is in PAL mode correctly (what does the z80 rea...
- Fri Apr 03, 2009 8:46 pm
- Forum: Megadrive/Genesis
- Topic: What are the 68K/Z80 clock spes for NTSC v PAL machines?
- Replies: 9
- Views: 7563
- Fri Apr 03, 2009 8:32 pm
- Forum: Megadrive/Genesis
- Topic: What are the 68K/Z80 clock spes for NTSC v PAL machines?
- Replies: 9
- Views: 7563
Okay I think I might know what my issue is then. I'm not taking into account that PAL has more scan lines than NTSC. My current emulation main loop grabs a DAC sample once per NTSC scan line (224 active, 38 vblank = 262). I assume my main loop will need updating to take into account the extra PAL sc...
- Fri Apr 03, 2009 8:07 pm
- Forum: Megadrive/Genesis
- Topic: What are the 68K/Z80 clock spes for NTSC v PAL machines?
- Replies: 9
- Views: 7563
What are the 68K/Z80 clock spes for NTSC v PAL machines?
I'm looking into an issue where I've setup the emulated IO system VMOD and MODE into I'm running a PAL rom: PSG/YM2612 music tempo and frequency is playing at the correct speed, but YM2612 DAC sample playback is pitched down. The DAC is being driven by the Z80 which for my current PAL implementation...
- Wed Apr 01, 2009 5:36 am
- Forum: Megadrive/Genesis
- Topic: GoldenAxe missing magic blue bottle and palette corruption
- Replies: 11
- Views: 7999
Okay - so after looking over my int code very closely I found the real problem (ignore my last posts) and your info confirms this Eke. My previous 68k frame execute loop only checked for handling ints at the beginning of every scan line. I updated the code so that a check for ints is handled immedia...
- Wed Apr 01, 2009 3:35 am
- Forum: Megadrive/Genesis
- Topic: GoldenAxe missing magic blue bottle and palette corruption
- Replies: 11
- Views: 7999
thanks guys - yes that was a typo, but (luckily) it didn't caused any problems. anyway, now that I've fixed that, I think I've cracked the golden axe problems: 1) I do not trigger 68k vbl interrupts when the vdp display is disabled (happens when the screen is black just before a level starts in gold...
- Tue Mar 31, 2009 10:11 pm
- Forum: Megadrive/Genesis
- Topic: GoldenAxe missing magic blue bottle and palette corruption
- Replies: 11
- Views: 7999
Okay so I've found a solution and was wondering if anyone else is doing the same: Basically golden axe turns off the display during level initialization (when the bottle graphic is written to vram). Disabling vbl triggering when the display is turned off fixes the problem. I also implemented (what I...
- Tue Mar 31, 2009 8:14 pm
- Forum: Megadrive/Genesis
- Topic: GoldenAxe missing magic blue bottle and palette corruption
- Replies: 11
- Views: 7999
thanks for pointing out the small errors. they didn't actually solve the problem but that's because that was not the cause. I tracked down the issue to the main loop performing vram writes (for the bottle graphic), but it gets interrupted by a 68k vbl which performs a mem->cram dma. this trashes the...
- Tue Mar 31, 2009 10:12 am
- Forum: Megadrive/Genesis
- Topic: GoldenAxe missing magic blue bottle and palette corruption
- Replies: 11
- Views: 7999
A bit more info: From debugging I can see the bottle graphics being downloaded into cram instead of vram. (this would explain the missing bottle, and the corrupt palette). Can you spot anything wrong with my code register update? This is the only function where I update it: cheers, Steve void VDP::W...