Content deleted Content added
No edit summary |
No edit summary |
||
Line 5:
AGA is able to display graphics modes with a depth of up to {{nowrap|8 bit}} per pixel. This allows for {{nowrap|256 colors}} in indexed display modes and {{nowrap|262 144 colors}} (18-bit) in [[Hold And Modify|HAM]]-8 ([[Hold-And-Modify]]) modes. The palette for the AGA chipset has 256 entries from {{nowrap|16 777 216 colors}} (24-bit), whereas previous chip sets ([[Amiga Original chipset|OCS]] and [[Amiga Enhanced Chip Set|ECS]]) only allowed {{nowrap|32 colors}} out of 4096 (64 colors in [[Amiga Halfbrite mode|EHB mode]]). Other features added to AGA over [[Amiga Enhanced Chip Set|ECS]] were super hires smooth scrolling and 32-bit fast page memory fetches to supply the graphics data bandwidth for 8 bitplane graphics modes and wider [[Sprites (computer graphics)|sprites]].
AGA was an incremental upgrade, rather than the dramatic upgrade of the other chipset that Commodore had begun in 1988, [[AAA chipset|AAA]], lacking many features that would have made it competitive with other graphic chip sets of its time. Apart from the graphics data fetches, AGA still operates on 16-bit data only, meaning that a lot of bandwidth is wasted during register accesses and [[Amiga Original chipset#Copper|copper]] and [[blitter]] operations. Also the lack of a [[packed pixel|chunky]] graphics mode is a speed impediment to graphics operations not tailored for [[Planar (computer graphics)|planar]] modes, as well as resulting in ghost artifacts during the common productivity task of [[scrolling]]. In practice, the AGA HAM ([[Hold-And-Modify]]) mode is mainly useful in painting programs, picture viewers and for video playback. Workbench in 256 colors is much slower than [[Amiga Enhanced Chip Set|ECS]] operation modes for normal application use; a workaround is to use multiple screens with different color depths. AGA also lacks flicker free higher resolution modes, being only able to display {{nowrap|640 × 480}} at {{nowrap|72 Hz}} flicker-free operation. {{nowrap|800 × 600}} mode is rarely used as it could only operate at a flickering {{nowrap|60 Hz}} interlaced mode. In contrast, higher-end PC systems of this era could operate {{nowrap|1024 × 768}} at {{nowrap|72 Hz}} with a full 256-color display. AGA's highest resolution is {{nowrap|1440 × 580}} {{nowrap|(262 144 colors)}} in interlaced {{nowrap|50 Hz}} {{nowrap|PAL mode,}} when overscan was used.
These missed opportunities in the AGA upgrade contributed to the [[Amiga]] ultimately losing technical leadership in the [[multimedia]] area. AGA was to be succeeded by the [[Hombre chipset]], after the long delayed AAA was finally shelved, which was ultimately cancelled due to Commodore's [[bankruptcy]].
| |||