4 ms·

> Sound blaster (8 bit sound card) and VGA (only 256 colors at once at low resolution, and no sprites) The color depth of the OCS and VGA are not directly comp

> Sound blaster (8 bit sound card) and VGA (only 256 colors at once at low resolution, and no sprites) The color depth of the OCS and VGA are not directly comparable. OCS and ECS allowed 32 out of 4096 colors at once. To reach the full 4096 you needed to use HAM, which while impressive, was not as flexible and required careful image design. VGA allowed 256 out of 262 144, to get something similar in the Amiga you needed AGA.

beagle3 6y ago
While true, VGA only did that at 320x200, HAM6 was 360x576 with sprites, and iirc split screen with other modes was already possible. It is not directly comparable, not being pixel addressable, but was incredibly useful for anything that wasn’t fast moving and had some time to optimize the displayed image. It also took a while for anything actually use 256 color VGA for more than mostly static pictures. I wrote a side scroller in 1993 for the PC. I had to resort to a weird mode whose name escapes me now, where you could only address every 4th pixel without a bank switch - without this. Scrolling was too slow and there was no double buffering on VGA. It became the norm around 1994-1995 but without it, screen updates were severely limited by CPU speed.
- pezezin 6y ago
  Mode X? With mode X you could reach weird resolutions like 320x480 with 256 colors, but it was planar.
- vardump 6y ago
  "While true, VGA only did that at 320x200" I remember being able to get VGA to run at 360x480 with 256 colors in mode-x. "I had to resort to a weird mode whose name escapes me now, where you could only address every 4th pixel without a bank switch" That's mode-x. You could also for example set all 4 pixels to same color with a single write, write mask was a 4-bit value. It was great for filling polygons.
vardump 6y ago
"OCS and ECS allowed 32 out of 4096 colors at once." Per horizontal line! Copper could swap out palettes between/during horizontal lines. There was also 64-color extra halfbrite mode. Another 32 colors were at 50% brightness.
- pezezin 6y ago
  Was it fast enough to replace the palette during horizontal blanking? A quick Google search took me to this forum: http://eab.abime.net/showthread.php?t=50518 http://eab.abime.net/showthread.php?t=50518 According to the information provided there, trying to do a 32-color full palette swap every scanline would starve the CPU.
  - vardump 6y ago
    Yeah, it would steal a lot of DMA time, and would starve a CPU not executing code & accessing data in the Fast RAM. But at least you can display pretty pictures without HAM fringing. :-)
    - pezezin 6y ago
      Fair enough. I'm always amazed at the kind of tricks expert programmers could pull off on those old 2D machines. Have you seen the Sega MegaColor demo? A crazy guy managed to play full color video at 30 fps in the Sega Megadrive. No graphics, no sprites, just change the background color for every pixel through DMA!
- ChainOfFools 6y ago
  to be fair these copper list tricks had their own performance tradeoffs and didn't see any use at all for years after the Amiga was introduced, and even then only really suited static image display. nonetheless I still fondly recall the thrill of seeing the all-stops-out pinnacle of this technique in a demo that ran at super hires, extended overscan PAL interlace, displaying a pin sharp image of portraits and wildlife in full 4096 color depth at something like 1510 x 602, on 1989 (!) consumer hardware (Amiga 3000).

beagle3 6y ago

While true, VGA only did that at 320x200, HAM6 was 360x576 with sprites, and iirc split screen with other modes was already possible. It is not directly comparable, not being pixel addressable, but was incredibly useful for anything that wasn’t fast moving and had some time to optimize the displayed image. It also took a while for anything actually use 256 color VGA for more than mostly static pictures. I wrote a side scroller in 1993 for the PC. I had to resort to a weird mode whose name escapes me now, where you could only address every 4th pixel without a bank switch - without this. Scrolling was too slow and there was no double buffering on VGA. It became the norm around 1994-1995 but without it, screen updates were severely limited by CPU speed.

pezezin 6y ago
Mode X? With mode X you could reach weird resolutions like 320x480 with 256 colors, but it was planar.
vardump 6y ago
"While true, VGA only did that at 320x200" I remember being able to get VGA to run at 360x480 with 256 colors in mode-x. "I had to resort to a weird mode whose name escapes me now, where you could only address every 4th pixel without a bank switch" That's mode-x. You could also for example set all 4 pixels to same color with a single write, write mask was a 4-bit value. It was great for filling polygons.

vardump 6y ago

"OCS and ECS allowed 32 out of 4096 colors at once." Per horizontal line! Copper could swap out palettes between/during horizontal lines. There was also 64-color extra halfbrite mode. Another 32 colors were at 50% brightness.

pezezin 6y ago
Was it fast enough to replace the palette during horizontal blanking? A quick Google search took me to this forum: http://eab.abime.net/showthread.php?t=50518 http://eab.abime.net/showthread.php?t=50518 According to the information provided there, trying to do a 32-color full palette swap every scanline would starve the CPU.
- vardump 6y ago
  Yeah, it would steal a lot of DMA time, and would starve a CPU not executing code & accessing data in the Fast RAM. But at least you can display pretty pictures without HAM fringing. :-)
  - pezezin 6y ago
    Fair enough. I'm always amazed at the kind of tricks expert programmers could pull off on those old 2D machines. Have you seen the Sega MegaColor demo? A crazy guy managed to play full color video at 30 fps in the Sega Megadrive. No graphics, no sprites, just change the background color for every pixel through DMA!
ChainOfFools 6y ago
to be fair these copper list tricks had their own performance tradeoffs and didn't see any use at all for years after the Amiga was introduced, and even then only really suited static image display. nonetheless I still fondly recall the thrill of seeing the all-stops-out pinnacle of this technique in a demo that ran at super hires, extended overscan PAL interlace, displaying a pin sharp image of portraits and wildlife in full 4096 color depth at something like 1510 x 602, on 1989 (!) consumer hardware (Amiga 3000).