[hatari-devel] Extended video mode

Thomas Huth huth at users.berlios.de
Tue Mar 9 21:18:36 CET 2010


On Tue,  9 Mar 2010 15:08:30 +0100
ghst at ghstwlf.com wrote:

> Hello,
> I am looking in to extending the resolution of my atari st to
> someting like, 1280x1024 or even bigger. I want to do this by a small
> mod to the cardrige port by adding WE in some way. Now I am curios
> how Hatari does its extended grafics mode. I have tried to read the
> code but I can't make any sens of it. Please tell me. //Pär

 Hi!

IIRC we basically hook into the TRAP 2 vector to intercept the
v_openvwk() VDI call. When this call is made, we patch the new
resolution into the right entries of the intout array, and also
update some line-a variables. See vdi.c in the Hatari source code.

 Regards,
  Thomas


PS: I also got a small program (with source code!) called SCREENPLUS-2
on my harddisk, that extends the low GEM resolution of every real ST
from 320x200 to 320x240. If you like I can send that to you.



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