8 Construct a sound scheduler and a mixer.
11 slScheduler sched ( 8000 ) ;
16 mixer . setMasterVolume ( 30 ) ;
17 sched . setSafetyMargin ( 0.128 ) ;
19 /* Just for fun, let's make a one second synthetic engine sample... */
21 Uchar buffer [ 8000 ] ;
23 for ( int i = 0 ; i < 8000 ; i++ )
25 /* Sum some sin waves and convert to range 0..1 */
27 float level = ( sin ( (double) i * 2.0 * M_PI / (8000.0/ 50.0) ) +
28 sin ( (double) i * 2.0 * M_PI / (8000.0/149.0) ) +
29 sin ( (double) i * 2.0 * M_PI / (8000.0/152.0) ) +
30 sin ( (double) i * 2.0 * M_PI / (8000.0/192.0) )
33 /* Convert to unsigned byte */
35 buffer [ i ] = (Uchar) ( level * 255.0 ) ;
38 /* Set up four samples and a loop */
40 slSample *s = new slSample ( buffer, 8000 ) ;
41 slSample *s1 = new slSample ( "scream.ub", & sched ) ;
42 slSample *s2 = new slSample ( "zzap.wav" , & sched ) ;
43 slSample *s3 = new slSample ( "cuckoo.au", & sched ) ;
44 slSample *s4 = new slSample ( "wheeee.ub", & sched ) ;
46 /* Mess about with some of the samples... */
48 s1 -> adjustVolume ( 2.2 ) ;
49 s2 -> adjustVolume ( 0.5 ) ;
50 s3 -> adjustVolume ( 0.2 ) ;
52 /* Play the engine sample continuously. */
54 sched . loopSample ( s ) ;
56 int tim = 0 ; /* My periodic event timer. */
60 tim++ ; /* Time passes */
62 if ( tim % 200 == 0 ) sched.playSample ( s1 ) ;
63 if ( tim % 180 == 0 ) sched.playSample ( s2 ) ;
64 if ( tim % 150 == 0 ) sched.playSample ( s3 ) ;
65 if ( tim % 120 == 0 ) sched.playSample ( s4 ) ;
68 // introduce an envelope for our engine noise after 10 seconds
70 slEnvelope my_envelope ( 2, SL_SAMPLE_LOOP ) ;
71 my_envelope.setStep ( 0, 0.0, 1.0 ) ;
72 my_envelope.setStep ( 1, 10.0, 2.0 ) ;
73 my_envelope.setStep ( 2, 20.0, 1.0 ) ;
75 // scheduler -> playSample ( my_sample ) ;
76 sched.addSampleEnvelope ( s, 0, 0, &my_envelope, SL_PITCH_ENVELOPE ) ;
81 For the sake of realism, I'll delay for 1/30th second to
82 simulate a graphics update process.
86 Sleep ( 1000 / 30 ) ; /* 30Hz */
88 sginap( 3 ); /* ARG */
90 usleep ( 1000000 / 30 ) ; /* 30Hz */
94 This would normally be called just before the graphics buffer swap
95 - but it could be anywhere where it's guaranteed to get called