Ä Area: [FIDO] PSION echo ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
  Msg#: 8487                                         Date: 20 Feb 95  19:27
  From: Faye Pearson                                 Read: Yes    Replied: No 
    To: Paul Hargreaves                              Mark:                     
  Subj: SND: guide Pt 2/2
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
This is Part 2/2 of my SND: driver lecture <g>

These are some OPL hints and they are all mine (Faye) they are
untested and I provide no warranty should they reduce your Psion to
a smoldering heap of ashes or otherwise decrease your happiness
you are free to use them with no strings whatsoever. :-)

This said I have used most of them myself and not had any problems...

-!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!-

This is an array of note values for use with the following formula

  f%(3)=3 :f%(4)=5 :f%(5)=7 :f%(6)=8 :f%(7)=10 :f%(1)=12 :f%(2)=14
  f%(11)=4 :f%(12)=6 :f%(14)=9 :f%(15)=11 :f%(9)=13

  freq%=INT(440*2**(f%(n%-64+s%)/12.0+o%-2.0))

This formula calculates a note frequency where:
  n% is the ASCII value of the note (ABCDEFG)
  s% is 0 if a natural and 8 if a sharp note
  o% is the octave number

In the following code these variables are used:
  shan%  : handle of the opened SND: device
  C1St%,
  C2St%  : Status variables for music (should be GLOBAL for safety)
  C1Buf%,
  C2Buf% : Pointer to buffer containing note information.
  C1Siz%,
  C2Siz% : Number of notes in buffer.
  ret%   : Variable for receiving return codes from IOW
  Play%  : Flag showing if music is/was playing

Playing music in foreground

  IOC(Shan%,1,C1St%,#C1Buf%,C1Siz%)
  ret%=IOW(Shan%,2,#C2Buf%,C2Siz%)
  IF ret%<0
    REM ERROR - music probably unplayed
  ENDIF
  IOWAITSTAT C1St%
  IF C1St%<0
    REM ERROR - music probably unplayed
  ENDIF

  Will play the music and the program will continue when the music is
  complete

Playing music in background

  IF Play%=0
    Play%=1
    IOC(Shan%,1,C1St%,#C1Buf%,C1Siz%)
    IOC(Shan%,2,C2St%,#C2Buf%,C2Siz%)
  ENDIF

If your program is IO driven (best)

  IOWAIT
  IF C1St%<>-46 AND C2St%<>-46 AND Play%=1
    REM music has just finished
    IF C1St%<0 OR C2St%<0
      REM ERROR - music probably unplayed
    ENDIF
    Play%=0
  ENDIF
  ...
  REM Your other async handling routines here
  REM like keyboard and timer...
  REM you don't need another IOWAIT
  ...

Otherwise...

  IF C1St%<>-46 AND C2St%<>-46 AND Play%=1
    IOWAITSTAT C1St%
    IOWAITSTAT C2St%
    REM music has finished!
    IF C1St%<0 OR C2St%<0
      REM ERROR - music probably unplayed
    ENDIF
    Play%=0
  ENDIF

Should be placed wherever you want to check if music has finished.

Remember the speaker can only do one thing at once.

I hope that is useful to you,
Faye.


ž P3aOLR 2.2 ž There's one reborn every minute

-!- Olms 2.0 [PCTDH49H]
 ! Origin: From The Crystal Tower : London (081-4478244) (2:254/220)