Interesting, I need 50% (1 sample burst per scan line instead of 1 sample burst per 1.5 scan lines), so that would leave 25% lacking. On the other hand, bursting per scan line would get rid of the manual timing to get burst at half lines. To be continued.
Got the between, thanks – rereading the source I see that a maximum of 11 palette entries are adjusted between the lines. So there is room for a - cpu intensive – let’s follow the scan line ‘rainbow processor’ on the SAM. Get your act together Si! ;-) From: [email protected] [mailto:[email protected]] On Behalf Of Aleš Keprt Sent: woensdag 11 april 2012 23:59 To: [email protected] Subject: Re: SAM HAM viewer I expect approximately +25% speed gain in uncontended memory. And Simon Owen wrote that he changes palette only “between” lines. Aley From: Stefan Drissen <mailto:[email protected]> Sent: Wednesday, April 11, 2012 11:42 PM To: [email protected] Subject: Re: SAM HAM viewer Jumping in a bit late here, but the results are absolutely stunning! I had an attempt at reading the source on github, but my Z80 has gone a bit rusty. :-) Is the palette being adjusted multiple times while the line is being drawn (similar to the rainbow processor effects on the Spectrum) or is the palette being adjusted in the time between two lines? Please forgive me for talking potential nonsense - I have completely lost any notion of how many t-states are available between line end and next line start but the expensiveness of outs does ring a bell somewhere. On another note (to hijack the thread), RJ does have some interesting ideas between all his communication issues and his one meg 128k emulator 'pestering' got me thinking - if this is uncontended RAM - how much could I win in the SAM MOD player if I moved code and data to make use of the one meg. Obviously larger mods would be interesting, but I'm more interested in would I be able to increase the sample rate from 10.4 KHz to 15.6 KHz? Or is the gain from uncontended vs contended RAM much too small? Regards, Stefan On Sat, Mar 24, 2012 at 3:10 AM, Simon Owen <[email protected]> wrote: Hi all, I've been experimenting with HAM-style tricks on SAM, to try to improve the quality of converted images. I've aimed to modify as many colours as possible between lines, rather than using the traditional compromise static palette. Are there any viewers using that technique already? I've written a Python script to convert regular images to a new .sham format, and a SAM viewer program to display them. Demo: http://simonowen.com/sam/shamview/shamview.dsk Source code: https://github.com/simonowen/shamview You might recognise some of them as SAM or image processing favourites! It still needs work on the dynamic palette selection, which just uses the most-frequent colours, rather than doing proper quantisation. I left the crayons image as an example of this breaking down. Si ----------------------------------------- Mgr. Aleš Keprt, Ph.D. private: [email protected], www.keprt.cz office: Moravian College / Moravská vysoká škola Olomouc, [email protected]
