ref: 1600d38f2374f2418c124feec565f50cf7c8f7c4
parent: 596bb7a2ddf8b005602fcb0f4db741333d5f0b30
author: rodri <rgl@antares-labs.eu>
date: Mon Jun 9 12:18:46 EDT 2025
new toy: beatlet
--- /dev/null
+++ b/beatlet.c
@@ -1,0 +1,204 @@
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include <draw.h>
+#include <mouse.h>
+#include <keyboard.h>
+#include <geometry.h>
+
+enum {+ NSAMP = 1323, /* 30ms */
+};
+
+static int debug;
+
+static Point2 ZP2 = {0,0,1};+RFrame beatrf;
+Image *screenb;
+Channel *drawc;
+
+Point2
+p2(Point p)
+{+ return Pt2(p.x, p.y, 1);
+}
+
+Point
+p2p(Point2 p)
+{+ return Pt(p.x, p.y);
+}
+
+Point
+toscreen(Point2 p)
+{+ return p2p(invrframexform(p, beatrf));
+}
+
+void
+redraw(void)
+{+ lockdisplay(display);
+ draw(screen, screen->r, screenb, nil, screenb->r.min);
+ flushimage(display, 1);
+ unlockdisplay(display);
+}
+
+void
+drawproc(void *arg)
+{+ Channel *c;
+
+ threadsetname("drawproc");+
+ c = arg;
+
+ for(;;){+ recv(c, nil);
+ redraw();
+ }
+}
+
+void
+beatproc(void *arg)
+{+ Point2 v;
+ Point poly[NSAMP];
+ u32int ss[NSAMP]; /* stereo samples */
+ s32int as[NSAMP], s; /* avg'd samples */
+ u16int min, max;
+ int fd, i, ns;
+ double θ;
+ uvlong frame, t0, t1;
+ char buf[32];
+
+ threadsetname("beatproc");+
+ fd = *(int*)arg;
+ ns = frame = 0;
+
+ t0 = nsec();
+ while(readn(fd, ss, 2*2*NSAMP) > 0){+ min = 1<<15 - 1;
+ max = 0;
+ for(i = 0; i < nelem(ss); i++){+ s = (s16int)(ss[i] & 0xFFFF) + (s16int)(ss[i]>>16 & 0xFFFF);
+ /* [-2¹⁶, 2¹⁶) → [0, 2¹⁵) */
+ s = (s/2 + (1<<15))/2;
+ min = s < min? s: min;
+ max = s > max? s: max;
+ as[i] = s;
+ }
+ lockdisplay(display);
+ for(i = 0; i < nelem(as); i++){+ θ = 2*PI * ((double)(ns++ % NSAMP)/NSAMP);
+ v = Vec2(cos(θ), sin(θ));
+ s = as[i];
+ poly[i] = toscreen(addpt2(ZP2, mulpt2(v, 4*(s-min)*100/max)));
+// line(screenb, toscreen(ZP2), toscreen(addpt2(ZP2, mulpt2(v, 400))), 0, 0, 0, display->black, ZP);
+// line(screenb, toscreen(ZP2), toscreen(addpt2(ZP2, mulpt2(v, 4*(s-min)*100/max))), 0, 0, 0, display->white, ZP);
+ }
+ draw(screenb, screenb->r, display->black, nil, ZP);
+ fillpoly(screenb, poly, nelem(poly), 1, display->white, ZP);
+
+ if(debug){+ t1 = nsec();
+ snprint(buf, sizeof(buf), "%llud (%3.0fHz)", ++frame, 1e9/(t1-t0));
+ t0 = t1;
+ stringbg(screenb, addpt(screen->r.min, Pt(20, 20)), display->white, ZP, font, buf, display->black, ZP);
+ }
+ unlockdisplay(display);
+ nbsend(drawc, nil);
+ }
+}
+
+void
+key(Rune r)
+{+ switch(r){+ case Kdel:
+ case 'q':
+ threadexitsall(nil);
+ }
+}
+
+void
+resized(void)
+{+ lockdisplay(display);
+ if(getwindow(display, Refnone) < 0)
+ sysfatal("resize failed");+ freeimage(screenb);
+ screenb = allocimage(display, screen->r, screen->chan, 0, DBlack);
+ beatrf.p = p2(divpt(addpt(screen->r.min, screen->r.max), 2));
+ unlockdisplay(display);
+ nbsend(drawc, nil);
+}
+
+void
+usage(void)
+{+ fprint(2, "usage: %s /dev/audio\n", argv0);
+ exits("usage");+}
+
+void
+threadmain(int argc, char *argv[])
+{+ Mousectl *mc;
+ Keyboardctl *kc;
+ Rune r;
+ int fd;
+
+ ARGBEGIN{+ case 'd': debug++; break;
+ default: usage();
+ }ARGEND;
+ if(argc != 1)
+ usage();
+
+ fd = open(argv[0], OREAD);
+ if(fd < 0)
+ sysfatal("open: %r");+
+ if(initdraw(nil, nil, nil) < 0)
+ sysfatal("initdraw: %r");+ if((mc = initmouse(nil, screen)) == nil)
+ sysfatal("initmouse: %r");+ if((kc = initkeyboard(nil)) == nil)
+ sysfatal("initkeyboard: %r");+
+ beatrf.p = p2(divpt(addpt(screen->r.min, screen->r.max), 2));
+ beatrf.bx = Vec2(1, 0);
+ beatrf.by = Vec2(0,-1);
+ screenb = allocimage(display, screen->r, screen->chan, 0, DBlack);
+ if(screenb == nil)
+ sysfatal("allocimage: %r");+
+ drawc = chancreate(sizeof(void*), 1);
+ proccreate(drawproc, drawc, 8*1024);
+ proccreate(beatproc, &fd, 32*1024);
+
+ display->locking = 1;
+ unlockdisplay(display);
+ nbsend(drawc, nil);
+
+ for(;;){+ enum { MOUSE, RESIZE, KEYBOARD };+ Alt a[] = {+ {mc->c, &mc->Mouse, CHANRCV},+ {mc->resizec, nil, CHANRCV},+ {kc->c, &r, CHANRCV},+ {nil, nil, CHANEND}+ };
+
+ switch(alt(a)){+ case RESIZE:
+ resized();
+ break;
+ case KEYBOARD:
+ key(r);
+ break;
+ }
+ }
+}
--- a/mkfile
+++ b/mkfile
@@ -16,5 +16,6 @@
barycentric\
lineXcircle\
linetiler\
+ beatlet\
</sys/src/cmd/mkmany
--
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