From: jerry AT eteklabs DOT nospam DOT com (Scott "Jerry" Lawrence) Newsgroups: comp.os.msdos.djgpp Subject: Re: Allegro: Adding background music to old DOS game Date: Tue, 10 Feb 1998 10:29:58 -0500 Message-ID: References: <6bphi4$8r6$1 AT fu-berlin DOT de> Organization: e-TEK Labs NNTP-Posting-Host: dial-q-14.netacc.net Lines: 32 To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Precedence: bulk In the past, brenner AT biochem DOT mpg DOT de thusly spoke... > [ ... ] > > Now I'm a beginner in coding DOS system functions (though I did quite some > extensive Assembler programming on the Amiga some years ago) and after trying > to grasp the basic concepts of the Allegro library I concluded it would be a > wise idea to ask the professionals if this is possible using Allegro/djgpp at > all :) From what I learned so far it's pretty tricky to do complex tasks like > changing the running song in the MIDI routines *from out of an interrupt*, can > you give me some suggestions as how to do this? (Can I call the play_midi() > function from out of an interrupt handler? I'm pretty sure, I can't ;) Is > there an easy way to do this anyway?) How about the 0x21/open interrupt. Do I > use Allegro's _install_irq() routine to install my own handler? Now i'm not positive about any of this, but chances are that Ultima grabs all the hardware it can - including the timer interrupt (IRQ 0 i believe) which is also mirrored at int 1ch. My guess is that Ultima mucks with these, disabling any previously installed handlers. another thing to look out for is if you're using a soundblaster, there's a possibility that allegro will lock the hardware, so ultima will have no sound whatsoever. you might want to try making a simple TSR using allegro (which will end up taking a large chunk of conventional memory i would think.) that just plays a note every half second or so... then run ultima. you'd know right away if it would work. THere are docs on the net about making TSRs in DJGPP. or i could be wrong... -jerr