chjmartin2, on Thu Mar 8, 2012 2:28 PM, said:
Intellivision has a screen that is 159x96 bitmap. The processor being 800 kHz may be a problem...
I'm not sure. No idea. The Aquarius Z80 is at 3.5 MHz, but it isn't 16 bit...
I am sure something could definitely be done!
Well, it's not actually a bitmapped display, but rather character oriented like the Aquarius. It does allow you to define 64 character tiles with whatever you like, though, which would let you do an arbitrary bitmap.
The Intellivision's character grid has half as many characters across and vertically as compared to the Aquarius. It has a similar foreground/background color scheme, but is slightly more restrictive. So, color is definitely a challenge, and Intellivision's huge, chunky fonts probably won't work very well pretending to be hunks of video. That leads to using the GRAM in a bitmap-like way.
If you didn't mind having the video in a tiny window, you could probably do something that looks acceptable in black-and-white in a, say, 64 x 48 region of the screen at something less than 60fps. 64 x 48 would take up 48 of the GRAM cards. If you're super aggressive, you can update half of the GRAM cards every frame, so you could support a full bitmap refresh at 30fps. (You may
be able to update as many as 29 GRAM cards per frame, although you'd have to unroll the code 100%. If your bitmaps have repeated pairs of rows, you may be able to update even more cards, but the required ISR gets trickier.)
Probably the most straightforward way to get B&W in that scheme would be to set background cards to either "black & grey" or "grey & white" or "black & white". You can maybe use MOBs to clean up places where you need a lot of black, grey and white simultaneously.
None of this considers the audio. The STIC cycle-steals from the CPU, so doing PCM playback via the PSG's volume registers (something both Arnauld and I have experimented with over the years) sounds pretty crummy unless you also blank the display. And if you're really soaking the GRAM to get the bitmap updates, that doesn't leave much, if anything, left for playing PCM data. You'd probably just want to stick to tracker-driven music like the C64 Dallas video.