CompuServe Messages

Josh, The Amiga AGA system is very unlike VGA in the sense that the 8-bit / 256 color mode is a _bitplane_ system, not a chunky-pixel system. That means that the gfx techniques used for VGA aren't, in general, appropriate for AGA use. Individual pixels must be written to 8 locations in memory, while masking previous information so it isn't affected; the overal efficiency is over 15 times lower under the AGA architecture for pixel-level techniques. Whole bitmaps are (relatively) easily moved using the Amiga's blitter, but that's a whole different programming style – and emulation of VGA under AGA means that things get "corner turned" to amke them work… read slow, not simply "not ideal". CBM knew that this architectural dichotomy would result in this problem (and others) but elected not to include corner-turning hardware in the AGA design. –Ben …via AutoPilot