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Old 19 August 2011, 16:36   #171
Join Date: Jun 2010
Location: out in the wild
Posts: 1,250
Originally Posted by NovaCoder View Post
A little birdy told me that we might be getting true color Graffiti after all (fingers crossed).
Did that little birdy also tell something about data rates? 3 bytes per pixel is a lot, and the "Graffiti" principle uses chipmem for the framebuffer, so you're limited to 2Mbytes.

Yes, you have full datarate on chipmem because you're only enabling 4 bitplanes, but with 7MBytes/second (or less if you have the wrong CPU card), this framebuffer is not exactly "high-performance".

For a really well-performing high-resolution and "lots-of-colours" screen, I'd vote for a combination of the following:

- keep the framebuffer in fastmem of accelerator
- use MMU routines to check for changes
- clever protocol for transferring changes to Indivision AGA MK2 framebuffer
(where "clever" includes runlength-encoding and window-drawing with modulo-copies)

This requires a lot of development on both the hardware and the software side. Luckily, such updates can be added when the hardware is in the field and basic functionality (it's still a flickerfixer!) is ensured on all systems. Gives me time to actually finish the hardware and some coders to show up and implement stuff ;-)

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