Date: Thu, 30 Apr 1998 18:19:20 +0200 (CEST)
From: Archee/CoNTRACT <01dsolt AT gondolat DOT vpg DOT hu>
To: Shadow Seeker <werewolf AT stad DOT dsl DOT nl>
cc: djgpp AT delorie DOT com
Subject: Re: sound
In-Reply-To: <6i9oth$o17$1@news.tudelft.nl>
Message-ID: <Pine.LNX.3.96.980430181147.448C-100000@Vpg02.vpg.hu>
MIME-Version: 1.0
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hi !

On Thu, 30 Apr 1998, Shadow Seeker wrote:

> >I'm diving further into sound programming and just got the wav part
> >to work.. Now i've been looking for info about sound mixing for
> >hours without finding anything comprehensible.. Is there someone out
> >there who holds the secret or know where it is?
> 
> 
> I solved this by creating four streaming buffers, four would be the number
> of channels you wish to use. And, you then take the average of the four
> buffers. And output that to the sound port like you would the data of a
> normal Wav file. Then when you wish to play a sound all you need to do is
> copy it to one of the channels.
> 
>  This is very basic, things get more complex when you wish to mix different
> frequencies, but it is mixing..
> 
> \/\/outer
> 
> 

Your algorithm is too slow !

Leave the samples in memory.
Make 4 struct for channels:

typedef struct {
 char *sample;
 long bytesleft;
 char volume;
 } CHANNEL;
CHANNELS chans[4];

sample=NULL, if no sound on that channel.
When you want to hear a sound, you put the address of the sound to
chan[x]. you have to find an x, when the chan[x].sample=NULL.
You put the len of the sample in chan[x].bytesleft and the volume to
chan[x].volume;

I think you dont need the volume, but you can code that too.
The maximum volume for chan[].volume is 64. (if there are four channels)

You have to multiple the sample with volume, than >>8 ofcoz in asm.

Copying is too slow.

I tell you, my engine after mixing does some FILTERING.

But my engine is not in DJGPP, and it only supports Sound Blaster.
It is not enought !

-- Archee/CoNTRACT  CODER   ( 01dsolt AT vpg DOT hu  )
oldnikk:stonee,sutyi
web: http://gondolat.vpg.hu/~01dsolt