Re: apple II 8bit sound programmers

["Michael J. Mahon" <mjmahon@aol.com>]

aiiadict@gmail.com wrote:
> hi,
>
> the level sequencer of my game allows you to specify:
> 0)time enemy appears
> 1)type of enemy
> 2)speed of enemy
> 3)location of enemy
>
> the code would work perfect for adding a sound routine
> (1bit speaker sound)...
>
> I would need 1) a song ---in  a format similar to this:
>
> time=0  note = 4
> time=1  note = 3
> time=2  note = 2
> time=3  note = 3
> time=4  note = 4
> time=5  note = 4
> time=6  note = 4
>
> can anyone name that tune?  :-)

Mer-ri-ly we roll a-long...  ;-)

> and a small routine to play the note
>
> ldy duration          ;duration is fixed in this example
>   loop0
>     lda speaker
>
>     ldx note,time        ;  note = frequency of sound to play
>     loop
>     dex                      ;
>     bne loop              ;
>
> dey
> bne loop0
>
>
> anyone interested in writing a simple tune for an
> arcade game?
>
> would be neat to have "I shot the sherrif" playing through
> the speaker as you shoot enemies :-)

In order to fit within your graphics time constraints, you'll
need to limit the durations of the notes--that may make them
pretty short.  In theory, the graphical manipulations could
be timed and fit into the delay loop, for simultaneous sound
and graphics updates--but that's quite a job!

RT.SYNTH saves music in a format <note #> <dur lo> <dur hi>
where:

note # is 0-127 (same note codes as MIDI)
       >127 = command (e.g. 128 = end, 129 = rest)

dur lo,dur hi = duration of note in 92 cycle units

It is easy to pick out tunes, record them, and save them.
An Applesoft program can then easily transform the music
file into any form you need, including assembler source.  ;-)

-michael

Music synthesis for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

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