How to create destroyable wheels: Difference between revisions

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==File Format==


{| border="1"
!Offset
!Datatype
!Content
!Description
|-
|0
|char[4]
|"WSS0"
|file signature
|-
|4
|ulong
|<compression>
|if <compression> == 8 the PCM data is compressed, otherwise <compression> == 0
|-
|8
|ushort
|<format tag>
|defines in which format the data is saved. Always 0x0001 in WSS files
|-
|10
|ushort
|<channels>
|number of channels: 1=mono, 2=stereo
|-
|12
|ulong
|<sample rate>
|sample rate in Hz (e.g. 44100Hz)
|-
|16
|ulong
|<bytes/second>
|<sample rate> * <block align>
|-
|20
|ushort
|<block align>
|<channels> * (<bits/sample> / 8)
|-
|22
|ushort
|<bits/sample>
|usually 0x0010 in WSS files
|-
|24
|ushort
|<unknown>
|unknown value
|-
|26
|byte[fileSize-26]
|<soundData>
|here the PCM data of the sound is stored
|-
|}
==Decompression==
If the <soundData> is compressed the following (C#) code can be used for decompression:
PCMData = new Int16[soundData.Length];
for (int j = 0; j < PCMData.Length; j++)
{
  SByte srcSample = (SByte)soundData[j];
  if (srcSample != 0)
  {
    double asFloat = Math.Abs(srcSample) / 28.12574042515172;
    asFloat *= 2.3025850929940456840; //ln(10)
    asFloat *= 1.4426950408889634070; //log2(e)
    double rnd = Math.Round(asFloat);
    double mantisse = Math.Pow(2.0, asFloat - rnd);
    asFloat = mantisse * Math.Pow(2, rnd);
    if (srcSample < 0) asFloat *= -1;
    Int32 asInt = (int)Math.Round(asFloat);
    asInt = (j == 0) ? asInt : (asInt + PCMData[j - 1]);
    if (asInt > short.MaxValue) asInt = short.MaxValue;
    if (asInt < short.MinValue) asInt = short.MinValue;
    PCMData[j] = (Int16)asInt;
  }
  else PCMData[j] = (j == 0) ? (Int16)0 : PCMData[j - 1];
}

Revision as of 01:45, 25 January 2010

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