Further PERQ Emulator progress (and a download!)
ray at arachelian.com
Thu Jul 3 18:30:12 CDT 2008
Jim Battle wrote:
> Have a look at Qt. Have a look at wxWidgets (which is what I use).
> There is no need to write separate interfaces; in my experience, 98%
> of the code is the same across windows and osx (I haven't attempted to
> get a linux port running)
Indeed, I'm hearing very good things about Qt, and getting a bit of
pressure to rewrite LisaEm using that instead of wxWidgets, but I find
wxWidgets to be robust and perfectly fine for LisaEm. I'm not sure
what wxWidgets 3.0 will bring, but I'm looking forward to it. There
are of course licensing issues with Qt, but if you're not going to
produce anything commercial, it's perfectly fine to use Qt. Otherwise
wx seems a better choice.
wx has a hidden interface for directly manipulating wxBitmaps. wx is
very fast at blitting these to the display, but slow at drawing inside
wxBitmaps. I've managed to use the hidden rawbitmap interface very
nicely for both OS X and win32, however, under Linux it doesn't work too
well, so I've instead uses the wxImage classes and convert the image to
a wxBitmap before blitting. It's a little bit slower, but works just fine.
The only serious problem I've see with wx is the lack of proper sound.
It'll play WAV files just fine, but that's the problem - they must be
files. There is a way to load them in memory and play them back, but
I've found it doesn't always work, and I've had to compose a WAV file in
memory, write it to /tmp and then tell wx to play the file. I'm sure I
could use some other library such as Allegro for this, but meh, it
really should be properly handled under wx. (I've no idea if this is
handled properly in Qt or not.)
For sound emulation you want to be able to compose a sound buffer
containing the wave and play it back on the fly and also you should be
able to add more data to the sound buffer or somehow work with it like a
circular buffer... Lisa's sounds are very limited (just square waves
produced by a VIA's shift register, so it's not too bad.)
Ideally you should be able to play MIDI files (or play them from
memory), work with multiple voices, and be able to handle envelopes for
notes, etc. it would be really cool for example to be able to build a
C64 SID emulator using wxWidgets for example.
Of course the real problem is that since it was written in .NET it will
have to be a whole rewrite into C or C++ or something that either Qt or
wx supports. I'd opt for pure C for all the low level stuff and C++ or
something else for the UI. mono and .Net are nice and all, but I'd say
they're far from an ideal platform for an emulator. Yes, I know,
there's a PC emulator written in JAVA, today's machines are capable of
running an emulator inside a virtual machine (ok, with JIT compilation),
but why put up with all the overhead?
wxWidgets works beautifully under Linux with GTK. I've had issues
providing binaries that would work under multiple distros (it's hard to
compile statically with GTK), so perhaps it's best to just provide
source and contact the ports managers for the distros you're interested
There's also a pure X11 version of wxWidgets that can be used, but I've
found it clunky and slow compared to the GTK one - and also some stuff
that worked under GTK didn't work under X11 there. But GTK is fairly
universal. (Ok, it would be nice if a wxQT existed too, but that's less
critical.) I haven't been able to get LisaEm to work under Solaris,
although it should, it's probably some sort of endian issue or
something, but there is a wxMotif as well - certainly would work on any
platform that still uses Motif, though it might run better if GTK+ was
installed on Solaris... :-)
One idea I'ved toyed with but haven't done anything with is using wxLua
as the UI and C for the core emulation. It might be worth looking at,
well providing you allow the C code to do all the heavy work of
refreshing the display as well. The benefit here is that it makes it
easier to edit the UI.
Anyway, I'm very happy to see a PERQ emulator, in any form.
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