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stk/doc/doxygen/realtime.txt
Gary Scavone 6e0d1955a8 Version 4.1.1
2013-09-29 23:05:09 +02:00

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/*! \page realtime Realtime Audio
In this section, we modify the <TT>sineosc.cpp</TT> program in order to send the output to the default audio playback device on your system.
\code
// rtsine.cpp
#include "WaveLoop.h"
#include "RtWvOut.h"
int main()
{
// Set the global sample rate before creating class instances.
Stk::setSampleRate( 44100.0 );
WaveLoop *input = 0;
RtWvOut *output = 0;
try {
// Define and load the sine wave file
input = new WaveLoop( "rawwaves/sinewave.raw", TRUE );
// Define and open the default realtime output device for one-channel playback
output = new RtWvOut(1);
}
catch (StkError &) {
goto cleanup;
}
input->setFrequency(440.0);
// Play the oscillator for 40000 samples
int i;
for ( i=0; i<40000; i++ ) {
try {
output->tick(input->tick());
}
catch (StkError &) {
goto cleanup;
}
}
cleanup:
delete input;
delete output;
return 0;
}
\endcode
The class RtWvOut is a protected subclass of WvOut. A number of optional constructor arguments can be used to fine tune its performance for a given system.
Though not used here, an RtWvIn class exists as well which can be used to read realtime audio data from an input device. See the <TT>record.cpp</TT> example program in the <TT>examples</TT> project for more information.
It is possible to use an instance of RtWvOut and an instance of RtWvIn to simultaneously read and write realtime audio to and from a hardware device or devices. However, it is recommended to instead use a single instance of RtDuplex to achieve this behavior, in that it guarantees better synchronization between the input and output data. See the <TT>effects</TT> project or the <TT>io.cpp</TT> example program in the <TT>examples</TT> project for more information.
When using any realtime STK class (RtAudio, RtWvOut, RtWvIn, RtDuplex, RtMidi, TcpWvIn, TcpWvOut, Socket, and Thread), it is necessary to specify an audio/MIDI API preprocessor definition and link with the appropriate libraries or frameworks. For example, the above program could be compiled on a Linux system using the GNU g++ compiler and the ALSA audio/MIDI API as follows (assuming all necessary files exist in the project directory):
\code
g++ -Wall -D__LINUX_ALSA__ -D__LITTLE_ENDIAN__ -o rtsine Stk.cpp WvIn.cpp WaveLoop.cpp WvOut.cpp \
RtWvOut.cpp RtAudio.cpp rtsine.cpp -lpthread -lasound -lstk
\endcode
On a Macintosh OS X system, the syntax would be:
\code
CC -D__MACOSX_CORE__ -o rtsine Stk.cpp WvIn.cpp WaveLoop.cpp WvOut.cpp RtWvOut.cpp RtAudio.cpp \
rtsine.cpp -lpthread -lstdc++ -lstk -framework CoreAudio -framework CoreMIDI -framework CoreFoundation
\endcode
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*/