Posted By
Luca
on 2025-03-29
11:16:43
 |  Re: Sound / Music
Oh well yes, that's like music: any sfx has its own little table of values, which get called every X times per frame and read by a tiny driver code which assigns the useful values to the right addresses ($FF0E/0F/10/11/12).
In BASIC, it would be something like:
100 VOL8
110 READ A,B:IF B=-1 THEN END
120 SOUND2,A,B:GOTO 110
130 DATA 700,1,800,1,900,1,950,1,965,1,967,1
140 DATA 960,2,878,2,700,3,440,3,200,4,,-1
Alternative sfx player can be envelope-based: the player considers a specified formula which uses a starting value only, or e.g. a starting value and a coefficient.
In BASIC, it would be something like:
100 VOL8:TT=0
110 INPUT "STARTING VALUE (0-1023)";VA
120 INPUT "COEFFICIENT (0-63)";CO
130 SOUND1,(VA*CO/(256-VA))AND255*4,1
140 SOUND2,ABS(VA-TT*CO),1
150 TT=TT+1:IF TT=21 THEN STOP
160 GOTO 130
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