paul@frcs.UUCP (Paul Nash) (03/26/91)
First off, many thanks to all those who responded to my plea about 320*200 256 colour BGI drivers for the VGA. Our mail system underwent some major changes (two trans-Atlantic links got cut off on the same day) around this time, so I am not sure that the replies got out. (If anyone wants the drivers, FTP them from SIMTEL (somewhere) or wuarchive.wustl.edu, in /mirrors/msdos/borland.) I am now trying (I think) to attempt the impossible. I am using a WD-based card (which is a clone of the Paradise chipset, I think), which has 512K of RAM onboard (far more than my first computer had!). I use the board exclusively in 640*400 mode, so I need less than 256K of RAM for my image. Does anyone, anywhere, know whether it is possible for me to write to one page of video RAM, and then swap pointers so that the screen just flips to a new image? I have no SVGA information, but know that this can be done on a vanilla IBM VGA card, if the image uses less than 32K of RAM (it has a 16-bit pointer to the start of the image). However, I have no idea whether _any_ of the SVGA cards allow you to do this. If I have to change cards to do this, so be it ... I am prepared to hack up some assembler to do this, and can undergo all sorts of indecencies to get it working IF it is possible. If not, I would like to know, so that I can stop trying to convince a customer that ``well, I have never heard of anyone doing this, and no, I don't think that it is actually possible'', and just tell him straight out that it definitely cannot be done. Many thanks in advance -- even a deathly silence will speak volumes! ---=---=---=---=---=---=---=---=---=---=---=---=---=---=---=---=---=--- Paul Nash Free Range Computer Systems cc paul@frcs.UUCP ...!uunet!m2xenix!frcs!paul