Amiga 2000 Juiced Up Disk Testing - So Many Disks - The Disk Pile Grows - More Triage - Episode 1944
6More disks...some are good...some have checksum errors, some come up as bad, and some, well some seem ok, but are indeed a mystery...sigh...
Going through some more Amiga disks...these were in a boxed marked AGA Games...not sure what that means...but I will try to find out! So look below and you will see what AGA means...I had forgotten! Anyway, it is time to try to figure out what is what with some of these disks...much testing and sorting to be done!
I found this online...and it is starting to come back to me!
Amiga - Advanced Graphics Architecture (AGA) The later versions of Amiga computers, AGA (Advanced Graphics Architecture) used 8 bits per color channel (Red, Green and Blue), which meant that they could display a limited selection of colors (up to 256) from a total range of 16.7 million colors.
Amiga - Advanced Graphics Architecture (AGA)
The later versions of Amiga computers, AGA (Advanced Graphics Architecture) used 8 bits per color channel (Red, Green and Blue), which meant that they could display a limited selection of colors (up to 256) from a total range of 16.7 million colors.
In addition to supporting all the original Amiga (OCS and ECS Modes) modes, the AGA Amiga's allowed for two 16 color scrolling layers, each with their own 16 color palette. The front scrolling layer would use 15 visible colors because its first color index must be used for "transparent".
Though AGA Amigas could display 256 colors, it wasn't used much for games, due to the extra memory and drawing time required for the extra color data. In fact most fast action/arcade style games tended to use either 16 color or 32 color indexes. There are lots of ways to get more colors on screen though, and one of the most useful techniques is to avoid using the AGA Amiga's supported scrolling layers, and instead use sprites or "blitted" objects to create a back layer of scrolling.
On paper AGA Amigas seemed quite weak compared to 16 bit consoles like the MegaDrive and SNES, which could display drastically more sprites on-screen, as well as more colors per layer when using "dual playfield" scrolling where typically back layers scrolled more slowly than the foreground layer for a nice effect of depth.
The reason the Amiga's sprite capabilities were so limited is that the designers decided to use a different approach to handle the moving objects in games. Instead of powerful sprites, they gave the Amigas a custom "blitter" chip, which could blit (draw) nearly a million pixels per second, drawing directly into the background, capable of using some or all of the colors (indexes) used in the background. This could allow for a great many moving objects on screen, without the color limits, sprite-size, and number of sprite's per scan-line limits common to nearly all 16 bit consoles. Blitted objects also don't suffer the infamous "flicker" problem that sprites have when more than a specified amount end up occupying the same horizontal space on screen (scan-line).
When Amiga game creators wanted to add layered scrolling to their games using the standard methods they faced some severe limitations. For the AGA Amiga hardware to display 2 overlapping layers which could scroll individually, they had to break the available "bit-planes" into two layers of 4 bit planes each. This meant if you wanted to use true hardware based dual playfield scrolling on AGA Amiga's then the back layer was limited to 16 colors and the front layer was limited to 15 colors plus one index used to represent transparent pixels, so you could see the back layer behind it!
To make matters worse, the AGA Amiga couldn't rely on its weak sprite capabilities, (witch can have their own color indexes separate from the 32 used for the two layers) to make the front layer and moving objects more colorful like 16 bit consoles could. While the blitter could draw and move lots of objects on screen, it could only use those same 15 colors the front layer has at its disposal. What many Amiga developers did was use the few sprites the Amiga had to create a nice looking 16 color player character, but then would use the blitter for almost all other moving objects, effects and enemies. This typically meant a smoothly scrolling game with a noticeably duller and lower-colored foreground layer, enemy sprites and effects such as explosions than console games would have, because they would all have to share the same limited 15 color palette.
More sophisticated Amiga developers were able to use other methods, using the Amiga's custom chips in less straight forward ways to create much more impressive games which rivaled many console games including eventual ports of the same game.