Audio buffer processing functions

gistfile1.coffee

# Returns a reversed copy of the supplied sample buffer
reverse = (buffer) ->
  data = buffer.getChannelData 0
  ret = audioContext.createBuffer 1, data.length, 44100
  retData = ret.getChannelData 0
  i = 0
  j = data.length
  retData[i++] = data[j] while j--
  ret

# Returns a copy of the supplied sample buffer where the first chunk of
# the original buffer is copied repeatedly into the return buffer.
glitch = (buffer, size) ->
  data = buffer.getChannelData 0
  len = Math.floor(data.length / size)
  slice = data.subarray 0, len
  newBuffer = audioContext.createBuffer 1, data.length, 44100
  newData = newBuffer.getChannelData 0
  newData.set slice, (len * i) for i in [0..(size - 1)]
  newBuffer