/* how to build : gcc -lm r-sound1.c -o r-sound1 */ /* generate sound of the diffrential equation while solving the equation */ /* to modify the parameter value is possible by keyboard operation */ /* 微分方程式の解x,yを求めながら、 そのデータをステレオで音にして流すプログラム */ /* パラメータ値の変化がキーボード操作で可能 */ /* KITA Toshihiro http://t-kita.net */ /* license : public domain */ #include #include #include #include #include #include #include #define BUFSIZE 35280 double Time_step= 0.1; double a, b, c; /* PARAMETERS */ int ch; void RKutta(); void DefDxdt(); static int setup_dsp( int fd ); //// #include //#include // #include static struct termios initial_settings, new_settings; static int peek_character = -1; void init_keyboard(); void close_keyboard(); int kbhit(); int readch(); int main( int argc, char *argv[] ) { double total = 0.2; short BUF[ BUFSIZE ]; int fd, i, j, ii; int ct; double t,x,y,z,xx,yy,xxx; double m,n; double last_x=0.0, last_y=0.0, sect_x=0.0; char buf[80]; x= 1.495; y= 3.4824; z=5.1731; t= 0.0;/* 初期値を与える */ /* パラメータ設定 */ #if 0 a=0.14; b=2.0; c=4.0; #endif #if 0 a=0.173; /* 0.15: 4-period, 0.16: chaos, 0.168: full-band chaos */ b=0.2; c=5.7; #endif #if 1 a=0.3; b=2.0; c=4.0; #endif if ( ( fd = open( "/dev/dsp", O_WRONLY ) ) == -1 ) { perror( "open()" ); exit( 1 ); } /* /dev/dsp の設定*/ if ( setup_dsp( fd ) != 0 ) { fprintf( stderr, "Setup /dev/dsp failed.\n" ); close( fd ); exit( 1 ); } printf("Use key p or n to change parameter value. Key q to quit.\n"); init_keyboard(); for(j=0; j<=3000; j++){ // ------------------------------------ if (kbhit()){ ch = readch(); /* printf("%d ",ch); fflush(stdout); */ if (ch==113){ close_keyboard(); exit(1); } // q if (ch==112){ a+= 0.01; printf("a = %g\n",a); } // p if (ch==110){ a-= 0.01; printf("a = %g\n",a); } // n if (ch==111){ close_keyboard(); printf("a = "); scanf("%lf",&a); init_keyboard(); } // o } for ( i = 0; i < BUFSIZE; i=i+2 ){ t = ( total / BUFSIZE ) * i; /* yy = y; xx = x; */ RKutta(&t,&x,&y,&z); /* if( yy<=0 && y>=0 ){ ii++; m = (y-yy)/(x-xx); n = m * (-xx) + yy; xxx = -(n/m); printf("%g %g %d\n",xxx,a,ii); } */ BUF[i] = SHRT_MAX * x * 0.1; BUF[i+1] = SHRT_MAX * y * 0.1; if (BUF[i]>=(SHRT_MAX-1) || BUF[i]<=-(SHRT_MAX-1)){ fprintf(stderr,"distortion!!\n"); } } if ( write( fd, BUF, sizeof(short)*BUFSIZE ) == -1 ) { perror( "write()" ); close( fd ); exit( 1 ); } } // --------------- for (j= ..) ---------------------- close_keyboard(); close( fd ); return 0; } void RKutta(double *t, double *x, double *y, double *z) { double k11,k12,k13,k21,k22,k23,k31,k32,k33,k41,k42,k43; double xt,yt,zt; DefDxdt(*t,*x,*y,*z,&k11,&k12,&k13); *t=*t+Time_step/2.0; xt=*x+(Time_step/2.0)*k11; yt=*y+(Time_step/2.0)*k12; zt=*z+(Time_step/2.0)*k13; DefDxdt(*t,xt,yt,zt,&k21,&k22,&k23); xt=*x+(Time_step/2.0)*k21; yt=*y+(Time_step/2.0)*k22; zt=*z+(Time_step/2.0)*k23; DefDxdt(*t,xt,yt,zt,&k31,&k32,&k33); xt=*x+Time_step*k31; yt=*y+Time_step*k32; zt=*z+Time_step*k33; *t=*t+Time_step/2.0; DefDxdt(*t,xt,yt,zt,&k41,&k42,&k43); *x+=Time_step*((k11+k41)/6.0+(k21+k31)/3.0); *y+=Time_step*((k12+k42)/6.0+(k22+k32)/3.0); *z+=Time_step*((k13+k43)/6.0+(k23+k33)/3.0); } void DefDxdt(time, x, y, z, dxdt, dydt, dzdt) double time, x, y, z, *dxdt, *dydt, *dzdt; { *dxdt= -y -z; *dydt= x + a*y; *dzdt= b + z*(x - c); } /* From http://homepage3.nifty.com/rio_i/lab/oss/index.htm */ /* * /dev/dsp を以下の様に設定する。 * * 量子化ビット数 : 16 bits * サンプリング周波数 : 44.1 KHz * チャンネル数 : 2 * PCM データは符号付き、リトルエンディアン * */ static int setup_dsp( int fd ) { int fmt = AFMT_S16_LE; int freq = 44100; int channel = 2; /* サウンドフォーマットの設定 */ if ( ioctl( fd, SOUND_PCM_SETFMT, &fmt ) == -1 ) { perror( "ioctl( SOUND_PCM_SETFMT )" ); return -1; } /* チャンネル数の設定 */ if ( ioctl( fd, SOUND_PCM_WRITE_CHANNELS, &channel ) == -1 ) { perror( "iotcl( SOUND_PCM_WRITE_CHANNELS )" ); return -1; } /* サンプリング周波数の設定 */ if ( ioctl( fd, SOUND_PCM_WRITE_RATE, &freq ) == -1 ) { perror( "iotcl( SOUND_PCM_WRITE_RATE )" ); return -1; } return 0; } /* From http://www.h3.dion.ne.jp/~unisoft/progbase.html */ void init_keyboard() { tcgetattr(0, &initial_settings); new_settings = initial_settings; new_settings.c_lflag &= ~ICANON; new_settings.c_lflag &= ~ECHO; new_settings.c_lflag &= ~ISIG; new_settings.c_cc[VMIN] = 0; new_settings.c_cc[VTIME] = 0; tcsetattr(0, TCSANOW, &initial_settings); } void close_keyboard() { tcsetattr(0, TCSANOW, &initial_settings); } int kbhit() { char ch; int nread; if(peek_character != -1) return 1; new_settings.c_cc[VMIN]=0; tcsetattr(0, TCSANOW, &new_settings); nread = read(0, &ch, 1); new_settings.c_cc[VMIN]=1; tcsetattr(0, TCSANOW, &new_settings); if(nread == 1) { peek_character = ch; return 1; } return 0; } int readch() { char ch; if(peek_character != -1) { ch = peek_character; peek_character = -1; return ch; } read(0, &ch, 1); return ch; }