A.D.A. Amiga Demoscene Archive

After discussing OS4 in another thread, and coming to the conclusion that not a lot of demos still use the custom chip set that much (so it seems at least), wouldn't it be cool to make them OS4/MorphOS compatible, while still being 68k demos ofcourse (hell, i still want to watch them) :)

So what is needed to make demos compatible with those systems? And would it be possible to make them compatible with both morphos and OS4. And is it worth the effort?

Now that i have written the first lines here, i'll leave it up to ppl who actually know what they are talking about :)

Its pretty easy... you can just download Cyborgs startup code from Aminet if you want to save yourself the effort... ;-)

Really, if you ONLY want 256 colour chunky effects, and want it to work on AGA, CGX, OS4 & MorphOS, you just open a 256 colour intuition screen and have an option of either using C2P on it (for AGA users), or WritePixelArray (for RTG, or BlazeWCP users). You have to time your effects and music through timer.device instead of CIAs or VBL interrupts.

You also need a system friendly replayer, which is probably the trickiest part.

On morphos the lowlevel.library is broken which was a very nice library for simple keystrokes and input controllers such as mice and joysticks. Stay away from that library too.

AHI (atleast my version) had a function that didn't work AHI_Play? When I switched to an older "obsolete" version of the function it worked... Can't remember exactly which function really, but it took some time to find that bug. On normal 68k amiga you don't really want to use AHI though as it is slow so stick to the paula on that platform.

So basically, you would need to detect which platform you run your demo on, and then either use a 68k sound replayer (theplayer61?) or AHI? Is that possible or too much work?

Load, aren't you using Cyborg's startup code since a long time (the credits in J'_ seem to hint at that)?

Yes I am, but because of The Player 6.1 and lowlevel.library you can't see all our demos since then on the new amigas.. THeres also some checking of left mousebutton in there and such, but no big deal to fix.. If someone made a source with the same functionality and interface as p61 I could port all the eph demos to the new machines easily.

anyone know of a good AHI protracker player with free source?

/me is also looking for one :D

IS NEEDED:

;; baaad:
jsr.l mysystemfunc(a6)
bne.s .no

; goood:
jsr.l mysystemfunc(a6)
tst.l d0
bne.s .no


...TO TEST THE FUCKING D0, THAT'S WHAT NEEDED.

@rload: ptplay I think.

@rload: ptplay I think

Can ptplay be used and integrated in demos, just like The Player?

I think it would actually be nice to have some of the classic (read: ephidrena :) ) demos on OS4.

ptplay is probably nice. I tried for half an hour once, but I mostly got annoyed with stuff not working right away even if they are boring.. does it report the e8x command?

-Use timer.device instead of CIAs
-Use AHI (I think digibooster can use AHI but I don't know if it requires CIAs to work...)
-Use Picasso96/CGX. Although WritePixelArray() is the easiest way to do it, it's damn slow, it's much faster to lock the screen bitmap, get the pointer to the screen and write directly to gfx memory, then you unlock the bitmap and continue. You can easily double the speed of your effect (depending on the effect, of course). Instead of writing to the chunky buffer, write directly to gfx ram :-)

One thing that is nice for ultimate cross-platform compatibility: Simple DirectMedia Layer (SDL).

For example, even if you have drawing stuff written in ASM for 68K Amigas, it would be nice to have an alternative rendering backend. That would allow demos to be ran on almost any platform. Of course, this means that you should use mostly C/C++.

Examples: Fit's demos, http://www.kameli.net/fit/productions/productions.html