Search found 152 matches
- Sat Nov 18, 2017 4:44 pm
- Forum: Megadrive/Genesis
- Topic: DMA transfer to CRAM visible however the screen is off.
- Replies: 28
- Views: 32859
Re: DMA transfer to CRAM visible however the screen is off.
There's a ROM release over at gamehut.com if anyone wants to inspect their technique and compare it to the modern one.
- Thu Oct 12, 2017 7:08 am
- Forum: Megadrive/Genesis
- Topic: DMA transfer to CRAM visible however the screen is off.
- Replies: 28
- Views: 32859
Re: DMA transfer to CRAM visible however the screen is off.
Bumping to make sure everyone knows that apparently, Traveller's Tales almost had direct color DMA in 1993, they just couldn't figure out how to sync to the VDP. Check this video.
- Wed Dec 09, 2015 8:55 am
- Forum: Megadrive/Genesis
- Topic: DMA transfer to CRAM visible however the screen is off.
- Replies: 28
- Views: 32859
Re: DMA transfer to CRAM visible however the screen is off.
It's my understanding that it is, as long as the additional RAM is wired up properly. Here's a thread about it.
- Wed Dec 09, 2015 8:22 am
- Forum: Megadrive/Genesis
- Topic: DMA transfer to CRAM visible however the screen is off.
- Replies: 28
- Views: 32859
Re: DMA transfer to CRAM visible however the screen is off.
Concerning the first: wouldn't it produce a lot of flickering?
Concerning the second: the architecture just doesn't allow it. Just impossible. Of course it would be good but if we would like just to dream about something then it's more reasonable to dream about some kind of modern GPU support for ...
Concerning the second: the architecture just doesn't allow it. Just impossible. Of course it would be good but if we would like just to dream about something then it's more reasonable to dream about some kind of modern GPU support for ...
- Wed Dec 09, 2015 7:47 am
- Forum: Megadrive/Genesis
- Topic: DMA transfer to CRAM visible however the screen is off.
- Replies: 28
- Views: 32859
Re: DMA transfer to CRAM visible however the screen is off.
Direct color DMA is a clever hack (discovered by Oerg866 IIRC) that effectively gives you a low-res bitmap mode by abusing DMA to CRAM. The DMA engine can copy one word to CRAM for every 2 pixels (except for during VRAM refresh, which is why you see some weird doubling). So if you sync the 68K to ...
- Tue Dec 08, 2015 5:26 pm
- Forum: Megadrive/Genesis
- Topic: DMA transfer to CRAM visible however the screen is off.
- Replies: 28
- Views: 32859
Re: DMA transfer to CRAM visible however the screen is off.
I have yet to find an image that looks better with direct color DMA than with 8 static colors + 8 colors replaced per scanline. I mean, it's easy enough to generate such an image I suppose, but if you just take a random photograph, the resolution loss looks way worse than the color loss.
The best ...
The best ...
- Mon Dec 07, 2015 2:08 am
- Forum: Megadrive/Genesis
- Topic: DMA transfer to CRAM visible however the screen is off.
- Replies: 28
- Views: 32859
Re: DMA transfer to CRAM visible however the screen is off.
A possible idea I had one time (but never implemented) was to "overlap" color changes. What I mean is, group together each set of two scanlines, and change half the colors per line (8 per line should be fairly easy from what I understand, although I'm a little rusty and my knoledge is a bit outdated ...
- Mon Dec 15, 2014 11:17 pm
- Forum: Exodus
- Topic: Simplified release of Exodus 1.1 coming soon
- Replies: 34
- Views: 74551
- Tue Dec 02, 2014 6:55 am
- Forum: Tools
- Topic: Linux Genesis Dev Setup
- Replies: 125
- Views: 156777
I'm interested in exploring whether this toolchain can be ported to jailbroken iOS - I already have several non-standard (in iOS land) tools installed (gcc, etc) but I'm not sure if I have the full complement. I would love to be able to take my iPad around and code for the Genesis when I have some ...
- Wed Nov 26, 2014 5:05 pm
- Forum: Announcement
- Topic: Don't forget what SpritesMind is
- Replies: 17
- Views: 65697
- Fri Aug 29, 2014 3:42 am
- Forum: Demos
- Topic: Rom dumping over audio
- Replies: 5
- Views: 8369
- Wed Mar 12, 2014 8:12 am
- Forum: Exodus
- Topic: Removable test or visual artifact?
- Replies: 4
- Views: 23472
Those are bus conflicts resulting from writing to CRAM midframe. They're unavoidable on hardware, and also why commercial games generally wait until VInt to write to CRAM (or if they do write to CRAM mid-frame, they either limit the amount of data they write, or attempt to make the shitpixels less ...
- Fri Feb 28, 2014 4:38 am
- Forum: Demos
- Topic: Ocean Melody
- Replies: 6
- Views: 10221
- Fri Feb 28, 2014 4:38 am
- Forum: Demos
- Topic: Ocean Melody
- Replies: 6
- Views: 10221
- Sat Feb 15, 2014 7:49 pm
- Forum: Sound
- Topic: z80 clocks
- Replies: 32
- Views: 37143
Speaking from NTSC land here. The half-line causes the TV's raster to "fill in the spaces" between the lines of the first field with those of the second field, generating a 525-line interlaced display. Literally the only difference between 240p and 480i is that half-line. Technically, in 240p, you ...