ref: 33dd40832cfa17d473edc20452a3158373dd6e5e
parent: 525191c99f034ed807d670fabf634e36d36937d6
author: glenda <glenda@9front.local>
date: Fri Nov 27 01:36:14 EST 2020
waveform generator
--- /dev/null
+++ b/waves.c
@@ -1,0 +1,222 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <event.h>
+#include <thread.h>
+
+#define ROOT2 1.05946309436
+#define RATE 44100;
+
+Image *back;
+int rate;
+double tones[16];
+double *buf[2];
+double ab = 0.0;
+
+void
+redraw(Image *screen)
+{+ Rectangle r, dot, b;
+ int dur = rate/4;
+ int w, h;
+ int i;
+
+ draw(screen, screen->r, back, nil, ZP);
+
+ // balance
+ r = screen->r;
+ r.max.y = r.min.y + 30;
+ draw(screen, insetrect(r, 3), display->white, nil, ZP);
+ r.min.x += Dx(screen->r) * (ab + 1.0)/2.0 - 1;
+ r.max.x = screen->r.min.x + Dx(screen->r) * (ab + 1.0)/2.0 + 1;
+ draw(screen, r, display->black, nil, ZP);
+
+ // A
+ r = screen->r;
+ r.min.y += 30;
+ r.max.y -= 30;
+ r.max.x -= Dx(screen->r)/2;
+ r = insetrect(r, 3);
+ w = Dx(r);
+ h = Dy(r);
+ draw(screen, r, display->white, nil, ZP);
+ for(i = 0; i < dur; i++){+ dot = rectaddpt(Rect((int)(((double)i/dur) * w),
+ (int)(((buf[0][i] + 1.0)/2.0) * h),
+ (int)(((double)(i+1)/dur) * w),
+ (int)(((buf[0][i] + 1.0)/2.0) * h) + 1),
+ r.min);
+ draw(screen, dot, display->black, nil, ZP);
+ }
+
+ for(i = 0; i < 3; i++){+ r = screen->r;
+ r.min.y = r.max.y - 30;
+ r.max.x = r.min.x + Dx(r)/6;
+ b = insetrect(rectaddpt(r, Pt(Dx(r)*i, 0)), 3);
+ draw(screen, b, display->white, nil, ZP);
+ }
+
+ // B
+ r = screen->r;
+ r.min.y += 30;
+ r.max.y -= 30;
+ r.min.x += Dx(screen->r)/2;
+ r = insetrect(r, 3);
+ w = Dx(r);
+ h = Dy(r);
+ draw(screen, r, display->white, nil, ZP);
+ for(i = 0; i < dur; i++){+ dot = rectaddpt(Rect((int)(((double)i/dur) * w),
+ (int)(((buf[1][i] + 1.0)/2.0) * h),
+ (int)(((double)(i+1)/dur) * w),
+ (int)(((buf[1][i] + 1.0)/2.0) * h) + 1),
+ r.min);
+ draw(screen, dot, display->black, nil, ZP);
+ }
+
+ for(i = 0; i < 3; i++){+ r = screen->r;
+ r.min.y = r.max.y - 30;
+ r.max.x = r.min.x + Dx(r)/6;
+ b = insetrect(rectaddpt(r, Pt(Dx(r)*(i+3), 0)), 3);
+ draw(screen, b, display->white, nil, ZP);
+ }
+
+ flushimage(display, 1);
+}
+
+void
+eresized(int new)
+{+ if(new && getwindow(display, Refnone) < 0)
+ fprint(2,"can't reattach to window");
+ redraw(screen);
+}
+
+void
+audioproc(void *unused)
+{+ int i, j, step, dur;
+ double tone, sum;
+ short out;
+ char *buffer;
+ char str[6*16+2];
+ int k;
+ int fd = open("/mnt/monome/buttons", OREAD);+
+ if (fd < 0)
+ sysfatal("open /mnt/monome/buttons: %r");+
+ dur = rate/4;
+ buffer = malloc(dur * 2);
+
+ for(;;){+ for(j = 0; j < 16; j++){+ if (readn(fd, str, 6*16+2) != (6*16+2))
+ sysfatal("readn /mnt/monome/buttons: %r");+ k = atoi(&str[j*6]);
+ for(step = 0; step < dur; step++){+ sum = 0.0;
+ for(i = 0; i < 16; i++){+ if(k & (1<<i)){+ tone = tones[16 - i - 1];
+ sum += buf[0][(int)(step*(tone/4)) % dur] * (ab - 1.0) * -0.5;
+ sum += buf[1][(int)(step*(tone/4)) % dur] * (ab + 1.0) * 0.5;
+ }
+ }
+
+ out = (short)(sum * 2047.0 * pow(0.9999, step/10.0));
+ buffer[step*2+0] = out & 0xFF;
+ buffer[step*2+1] = (out >> 8) & 0xFF;
+ }
+ write(1, buffer, dur*2);
+ }
+ }
+
+ free(buffer);
+}
+
+void
+threadmain(int argc, char **argv)
+{+ int i, j;
+ int dur;
+ Mouse m;
+ Point xy;
+ int dx;
+
+ rate = RATE;
+ if(argc > 1)
+ rate = atoi(argv[1]);
+
+ dur = rate/4;
+
+ if(initdraw(0, 0, "waves") < 0)
+ sysfatal("initdraw: %r");+ einit(Emouse);
+
+ back = allocimage(display, Rect(0,0,1,1), CMAP8, 1, 0x777777FF);
+ if(back == nil)
+ sysfatal("allocimage: %r");+
+ buf[0] = malloc(dur * sizeof(double));
+ buf[1] = malloc(dur * sizeof(double));
+
+ for(i = 0; i < dur; i++)
+ buf[0][i] = buf[1][i] = cos(((double)i/dur)*2*PI);
+
+ for(i = 0; i < 16; i++){+ tones[i] = 220.0;
+ for(j = 0; j < i; j++)
+ tones[i] *= ROOT2;
+ }
+
+ eresized(0);
+ proccreate(audioproc, nil, 8192*8);
+
+ for(;;m = emouse()){+ if(m.buttons & 1){+ xy = subpt(m.xy, screen->r.min);
+ if (xy.y < 30) {+ ab = (double)xy.x / Dx(screen->r);
+ ab -= 0.5;
+ ab *= 2.0;
+ }
+ if ((screen->r.max.y - m.xy.y) < 30){+ dx = Dx(screen->r)/6;
+ if (xy.x < dx)
+ for(i = 0; i < dur; i++)
+ buf[0][i] = cos(((double)i/dur)*2*PI);
+ else if (xy.x < 2*dx) {+ for(i = 0; i < dur; i++)
+ buf[0][i] = 1.0;
+ for(i = dur/4; i < 3*dur/4; i++)
+ buf[0][i] = -1.0;
+ }
+ else if (xy.x < 3*dx) {+ for(i = 0; i < dur/2; i++)
+ buf[0][i] = -((double)i/(dur/2)*2.0-1.0);
+ for(i = dur/2; i < dur; i++)
+ buf[0][i] = -(0.75-((double)i/dur))*4.0;
+ }
+ else if (xy.x < 4*dx)
+ for(i = 0; i < dur; i++)
+ buf[1][i] = cos(((double)i/dur)*2*PI);
+ else if (xy.x < 5*dx) {+ for(i = 0; i < dur; i++)
+ buf[1][i] = 1.0;
+ for(i = dur/4; i < 3*dur/4; i++)
+ buf[1][i] = -1.0;
+ }
+ else if (xy.x < 6*dx) {+ for(i = 0; i < dur/2; i++)
+ buf[1][i] = -((double)i/(dur/2)*2.0-1.0);
+ for(i = dur/2; i < dur; i++)
+ buf[1][i] = -(0.75-((double)i/dur))*4.0;
+ }
+ }
+ redraw(screen);
+ }
+ }
+}