bB help requested for new tool atari-riff-machine

[kisrael]

Hi there!

 

I spent the last few weeks making https://alienbill.com/2600/atari-riff-machine/ - a simple browser-based looper/tracker for making Atari music.

 

 

It generates batari Basic code for the Atari - though I'm worried there's some glitch and the two tracks get out of synch in some circumstances - help appreciated with that. I couldn't reproduce the problem with small tracks, and the number of frames seems right... so either it's a weird page boundary thing? or maybe some glitch like if there's rests at the begining or end? Anyway the engine for the two voices is a hacked up version I made from @Random Terrain's sdata version (his had two voices but assumed they'd be moving indepdently)


 

[RevEng]

Better late than never?

 

The bug appears to be when you have two loops of differing length - say one is 16 beats and the other is 8. The current version of your code skips one frame when an EOF marker is found, so the 8 beat loop will drift 2 frames per song loop, and the 16 beat version will drift 1. Neither actually remains on beat, but the difference in EOFs encountered per song loop is what's causing the drift. Here's a quickly hacked version that immediately grabs new data on EOF. 

 

    rem  *****************************************************
    rem  *  Music Starter using sdata
    rem  *  Based on code posted in the Ballblazer thread at AtariAge:
    rem  *  http://www.atariage.com/forums/index.php?s=&showtopic=130990&view=findpost&p=1615280
    rem  *  Code adapted by Duane Alan Hahn (Random Terrain)
    rem  *  Code further modified by Kirk Israel
    rem  *  Explanation:
    rem  *  The 256-byte limitation is removed when using sdata.
    rem  *  You can fill a whole 4k bank with music if you want.
    rem  *****************************************************
 
    set smartbranching on
 
    rem  *****************************************************
    rem  *  Create aliases for variables
    rem  *****************************************************
    dim duration0=a
    dim duration1=b
 
    dim wastefulInitCheck=c
 
    dim datareader0=w ; just a reminder
    dim datareader1=x ; just a reminder
    dim datareader2=y ; just a reminder
    dim datareader3=z ; just a reminder
 
 
    rem  *  Volume off
    AUDV0=0
    AUDV1=0
 
    rem  *  Initialize duration and set up music
    duration0 = 1
    gosub MusicSetup0
 
    rem  *****************************************************
    rem  *  Main game loop starts here.
    rem  *****************************************************
MainLoop
 
    goto GetMusic0
GotMusic0
 
     if wastefulInitCheck = 1 then goto skipCheck
     wastefulInitCheck = 1
     duration1 = 1
     gosub MusicSetup1
skipCheck
 
    goto GetMusic1
GotMusic1
 
 
    drawscreen
 
    goto MainLoop
 
 
 
 
    rem  *****************************************************
    rem  *  Music
    rem  *****************************************************
GetMusic0
 
    rem  *  Check for end of current note
    duration0 = duration0 - 1
    if duration0>0 then GotMusic0
 
 
    rem  *  Retrieve channel 0 data
ReadMusic0
    temp4 = sread(musicData0)
    temp5 = sread(musicData0)
    temp6 = sread(musicData0)
 
 
    rem  *  Check for end of data
    if temp4=255 then duration0 = 1 : gosub MusicSetup0 : goto ReadMusic0
 
 
    rem  *  Play channel 0
    AUDV0 = temp4
    AUDC0 = temp5
    AUDF0 = temp6
 
    rem  *  Set duration
    duration0 = sread(musicData0)
    goto GotMusic0
 
 
MusicSetup0
    sdata musicData0 = y
   8, 4, 21, 15
   8, 4, 20, 15
   8, 4, 15, 15
   8, 4, 18, 15
   8, 4, 16, 15
   8, 4, 12, 15
   8, 4, 15, 15
   8, 4, 20, 15
   8, 4, 10, 15
   8, 4, 9, 15
   8, 4, 12, 15
   8, 4, 11, 15
     255
end
    return
 
 
GetMusic1
 
    rem  *  Check for end of current note
    duration1 = duration1 - 1
    if duration1>0 then GotMusic1
 
    rem  *  Retrieve channel 1 data
ReadMusic1
    temp4 = sread(musicData1)
    temp5 = sread(musicData1)
    temp6 = sread(musicData1)
 
 
    rem  *  Check for end of data
    if temp4=255 then duration1 = 1 : gosub MusicSetup1 : goto ReadMusic1
 
 
    rem  *  Play channel 0
    AUDV1 = temp4
    AUDC1 = temp5
    AUDF1 = temp6
 
    rem  *  Set duration
    duration1 = sread(musicData1)
    goto GotMusic1
 
MusicSetup1
    sdata musicData1 = w
   15, 4, 27, 2
   14, 4, 27, 2
   13, 4, 27, 2
   12, 4, 27, 2
   11, 4, 27, 2
   10, 4, 27, 2
   9, 4, 27, 2
   8, 4, 27, 2
   7, 4, 27, 2
   6, 4, 27, 2
   5, 4, 27, 2
   4, 4, 27, 2
   3, 4, 27, 2
   2, 4, 27, 2
   1, 4, 27, 2
   0, 0, 0, 60
     255
end
    return

 

Your tool actually served a very good use for me. I slowed down a sound effect 5x in audacity (with time stretch, so the pitches don't shift) and then played it and transcribed the pitches I heard into your tool. The playback in your tool allowed me to A:B compare the pitches to the sample. Then I hand-transcribed the data into the 7800basic sample format. The result was perfection. It's an unintended use for your tool, but an excellent one. So thanks for that, Kirk!

 

This works best when used with musical-like sound effects, no doubt, the kind we've discussed before.

 

[edit - just ran across a nasty bug in riff machine. If you accidentally type 0 into the beats field, the javascript code crashes and the app goes away. If you refresh it doesn't come back. Session data, I guess.]

[kisrael]

thanks for the assist!!!

I will look into updating that and finding the zero beats bug soon

[kisrael]

Fixed the 0-length bug, now going to look into upgrading the BASIC engine!