On Sun, Jan 12, 2003 at 01:46:52AM +0100, Thomas Harte wrote: > By the way, with respect to Elite, I once partially reverse engineered the ZX > Spectrum > version, which is visibly identical to the SAM version implying that all that > is running is the > Spectrum code and a mode 1 screen. In which case we are seeing the following > abuses > of the SAM hardware :
Did they use exactly the same file on the disk, just adding a BASIC program to switch into mode 1? If so, the SAM 'version' couldn't have taken longer than 5-10 minutes work, surely! This begs the question; how much did each version cost? > - mode 1 display, with obvious effects on running speed Presumably a good deal of work would be needed to slow the game back down to its original speed, after the framerate had been increased? > - software double buffering, even though in the SAM (and 128kb Spectrum, I > believe) > this can be achieved in hardware Yes, the SAM and Spectrum 128k do provide page flipping. If I remember correctly, you are limited to just two pages on the Spectrum 128k, but but on the SAM, any page in main memory may be used. I've not actually tried using page 31 in modes 3 and 4 yet, but I expect that this uses page 0 for the upper 8k of the video memory. I also wonder whether the extra memory would be of particular benefit. > If someone is planning on writing a new implementation of Elite for the SAM, > then it might > be worth noting that the original BBC Micro 6502 source has been released by > Ian Bell > but is nearly illegible. It has subsequently been converted into C using the > Allegro > graphics library by Christian Pinder, the source for which is available via > http://www.newkind.co.uk (see Elite : The New Kind, rather than the other). I > contributed the anti-aliased drawing routines, and a few other modifications > regarding > subpixel accuracy for that purpose! Somebody was showing me this at uni a while back, and my immediate thought was "hmm, this would make a SAM port a lot easier." I would need to read up on graphics before I could make a start on this though. I presume that there are no legal issues to worry about? Thanks, -- Stuart Brady
