#include "sl.h" #include "sm.h" #include /* Construct a sound scheduler and a mixer. */ slScheduler sched ( 8000 ) ; smMixer mixer ; int main () { mixer . setMasterVolume ( 30 ) ; sched . setSafetyMargin ( 0.128 ) ; /* Just for fun, let's make a one second synthetic engine sample... */ Uchar buffer [ 8000 ] ; for ( int i = 0 ; i < 8000 ; i++ ) { /* Sum some sin waves and convert to range 0..1 */ float level = ( sin ( (double) i * 2.0 * M_PI / (8000.0/ 50.0) ) + sin ( (double) i * 2.0 * M_PI / (8000.0/149.0) ) + sin ( (double) i * 2.0 * M_PI / (8000.0/152.0) ) + sin ( (double) i * 2.0 * M_PI / (8000.0/192.0) ) ) / 8.0f + 0.5f ; /* Convert to unsigned byte */ buffer [ i ] = (Uchar) ( level * 255.0 ) ; } /* Set up four samples and a loop */ slSample *s = new slSample ( buffer, 8000 ) ; slSample *s1 = new slSample ( "scream.ub", & sched ) ; slSample *s2 = new slSample ( "zzap.wav" , & sched ) ; slSample *s3 = new slSample ( "cuckoo.au", & sched ) ; slSample *s4 = new slSample ( "wheeee.ub", & sched ) ; /* Mess about with some of the samples... */ s1 -> adjustVolume ( 2.2 ) ; s2 -> adjustVolume ( 0.5 ) ; s3 -> adjustVolume ( 0.2 ) ; /* Play the engine sample continuously. */ sched . loopSample ( s ) ; int tim = 0 ; /* My periodic event timer. */ slEnvelope pitch_envelope ( 3, SL_SAMPLE_LOOP ) ; slEnvelope p_envelope ( 1, SL_SAMPLE_ONE_SHOT ) ; slEnvelope volume_envelope ( 3, SL_SAMPLE_LOOP ) ; while ( SL_TRUE ) { tim++ ; /* Time passes */ if ( tim % 200 == 0 ) sched.playSample ( s1 ) ; if ( tim % 180 == 0 ) sched.playSample ( s2 ) ; if ( tim % 150 == 0 ) sched.playSample ( s3 ) ; if ( tim % 120 == 0 ) sched.playSample ( s4 ) ; if ( tim == 60 ) { // introduce an envelope for our engine noise after 10 seconds pitch_envelope.setStep ( 0, 0.0, 1.0 ) ; pitch_envelope.setStep ( 1, 5.0, 2.0 ) ; pitch_envelope.setStep ( 2, 10.0, 1.0 ) ; p_envelope.setStep ( 0, 5.0, 2.0 ) ; volume_envelope.setStep ( 0, 0.0, 1.0 ) ; volume_envelope.setStep ( 1, 5.0, 2.0 ) ; volume_envelope.setStep ( 2, 10.0, 1.0 ) ; // scheduler -> playSample ( my_sample ) ; sched.addSampleEnvelope( s, 0, 0, &p_envelope, SL_PITCH_ENVELOPE ); sched.addSampleEnvelope( s, 0, 1, &volume_envelope, SL_VOLUME_ENVELOPE); } /* For the sake of realism, I'll delay for 1/30th second to simulate a graphics update process. */ #ifdef WIN32 Sleep ( 1000 / 30 ) ; /* 30Hz */ #elif defined(sgi) sginap( 3 ); /* ARG */ #else usleep ( 1000000 / 30 ) ; /* 30Hz */ #endif /* This would normally be called just before the graphics buffer swap - but it could be anywhere where it's guaranteed to get called fairly often. */ sched . update () ; } }