T
Das hier ist zwar Delphi, lässt sich aber ganz leicht auf C++ umschreiben, ist nicht alleine von mir, vieles aus dem Internet.
procedure MakeSound(Frequency, Duration : integer);
var
WaveFormatEx : TWaveFormatEx;
MS : TMemoryStream;
i, TempInt,
DataCount,
RiffCount : integer;
SoundValue : byte;
w : double; // omega ( 2 * pi * f)
const
Mono : Word = $0001;
SampleRate : integer = 11025; // 8000, 11025, 22050, or 44100
RiffId : string = 'RIFF';
WaveId : string = 'WAVE';
FmtId : string = 'fmt ';
DataId : string = 'data';
begin
with WaveFormatEx do begin
wFormatTag := WAVE_FORMAT_PCM;
nChannels := Mono;
nSamplesPerSec := SampleRate;
wBitsPerSample := $0008;
nAvgBytesPerSec := nSamplesPerSec * nBlockAlign;
nBlockAlign := (nChannels * wBitsPerSample) div 8;
cbSize := 0;
end;
MS := TMemoryStream.Create;
with MS do
begin
//Länge des Tones bestimmen
DataCount := (Duration * SampleRate) div 1000;
RiffCount := Length(WaveId)
+ Length(FmtId) + SizeOf(DWord)
+ SizeOf(TWaveFormatEx)
+ Length(DataId) + SizeOf(DWord)
+ DataCount;
Write(RiffId[1], 4); // 'RIFF'
Write(RiffCount, SizeOf(DWord)); // Dateigröße
Write(WaveId[1], Length(WaveId)); // 'WAVE'
Write(FmtId[1], Length(FmtId)); // 'fmt '
TempInt := SizeOf(TWaveFormatEx);
Write(TempInt, SizeOf(DWord)); // TWaveFormat größe
Write(WaveFormatEx, SizeOf(TWaveFormatEx)); // WaveFormatEx record
Write(DataId[1], Length(DataId)); // 'data'
Write(DataCount, SizeOf(DWord)); // soundgröße
//tonsignal beschreiben // Datenwerte
w := 2 * Pi * Frequency; // omega
for i := 0 to DataCount - 1 do begin
// wt = w *i / SampleRate
SoundValue := 127 + trunc(127 * sin(i * w / SampleRate));
Write(SoundValue, SizeOf(Byte));
end;
//Sound aus Speicher abspielen
sndPlaySound(MS.Memory, SND_MEMORY or SND_SYNC);
MS.Free;
end;
end;
