aUCBLogo Demos and Tests / makewav_sines

to makewav_sines
   rate=44100
   ntones=13
   size=Int rate*ntones/8
   wavHeaderType=(list
      [ChunkID word RIFF]
      [wavfilesize int]
      [RIFFtype word 4]   ;the last item is the string length

      [formatChunkID word fmt\ ]
      [formatChunkSize int 16]
      [compressionCode int16 1]
      [NumberOfChannels int16 1]
      (list "SampleRate "int rate)
      (list "BytesPerSecond "int rate*2)
      [BlockAlign int16 2]
      [BitsPerSample int16 16]

      [DataChunkID word data]
      (list "DataChunkSize "int size*2)
   )
   wavHeader=struct wavHeaderType
   wavHeaderSize=SizeOf wavHeader
   wavHeaderSizeHalf=int wavHeaderSize/2
   wavsize=wavHeaderSize+size*2
   wavHeader'RIFFtype=[WAVE]   ;example for setting a string
   wavHeader'wavfilesize=wavsize
;   pr wavHeader
   wav=Int16Array int wavsize/2
   setWriter wav
   typeBin wavHeader
   setWriter []
;   setReader wav
;   wh=readStructBin wavHeaderType
;   pr wh
;   setReader []
   ssize=Int size/ntones-1
   phi=0
   t=0
   t0=0
   dt=1/rate
   k=wavHeaderSizeHalf+1
   for [i 0 ntones-1]
   [   f=440*2^(i/12)
      for [j 0 ssize]
      [   t=t+dt
         phi=phi+f*(t-t0)
         t0=t
         wav.k=Int16 30000*(sin 360*phi)
         k=k+1
      ]
   ]
;   drawPlot
   playWave wav 0
end

to drawPlot
   WindowMode
   hideTurtle
   clearScreen
   PenUp
   setXY -400 0
   PenDown
   setXY rseqfa -400 400 Int wavsize/2 FloatArray wav
   updateGraph
end