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Altirra 1.4 released

Since things have come to a bit of a pause, I've pushed out a new release of Altirra, which is available on the Altirra main page. This version contains some major improvements to disk and sound emulation, as well as further tweaks to graphics and DMA timing for higher emulation accuracy.

Now available at that page is also the first main release of the Altirra Technical Reference Manual, which is a document containing everything I've learned about the Atari 8-bit hardware so far. It's also the first time I've tried to write a large document in OpenOffice Writer, with which I've had mixed success. I'd say OO.o Writer is definitely at the point where you can write good-sized documents in it, but not yet at the point where you can do a full book or professional-level PDFs with it. There are just too many restrictions in areas like PDF bookmark handling and outlining to make completely polished output. Nevertheless, the manual hasn't turned out too bad, and I hope it's useful to anyone still working on an 8-bit Atari or is interested in the details of how the hardware works.

A few people have reported problems with graphics output in this version with low-end integrated graphics cards. One reason for this is that, unlike VirtualDub, Altirra defaults to having the Direct3D9 display path enabled in order to gain hardware accelerated display of 8-bit data. Unfortunately, this path can be too demanding for really low-end GPUs. I need to figure out what's going on here because D3D9 is necessary for hardware accelerated display on Windows Vista and Windows 7 and I eventually want to switch the default in VirtualDub on those operating systems. In the meantime, if this happens to you, specify /ddraw or /gdi on the command line to force a lower display mode.


This blog was originally open for comments when this entry was first posted, but was later closed and then removed due to spam and after a migration away from the original blog software. Unfortunately, it would have been a lot of work to reformat the comments to republish them. The author thanks everyone who posted comments and added to the discussion.