ref: 168a16b70a928ed64061bdac7fc9d52235c3f9fc
author: rodri <rgl@antares-labs.eu>
date: Thu Feb 20 17:02:08 EST 2020
git release.
--- /dev/null
+++ b/dat.h
@@ -1,0 +1,32 @@
+#define DEG 0.01745329251994330
+#define Eg 9.81
+#define PIX2M 0.001
+#define M2PIX (1.0/PIX2M)
+
+enum {+ STACK = 8192,
+ SEC = 1000,
+ FPS = 60,
+};
+
+enum {+ Stheta = 0,
+ Spos,
+ Svel,
+ Sdeltax,
+ Seta,
+ SLEN,
+};
+
+typedef struct Vector Vector;
+typedef double Matrix[3][3];
+typedef struct Projectile Projectile;
+
+struct Vector {+ double x, y, w;
+};
+
+struct Projectile {+ Vector p, v;
+ double mass;
+};
--- /dev/null
+++ b/fns.h
@@ -1,0 +1,15 @@
+void addm(Matrix, Matrix);
+void subm(Matrix, Matrix);
+void mulm(Matrix, Matrix);
+void transm(Matrix);
+double detm(Matrix);
+Vector mulvecm(Vector, Matrix);
+Vector Vec(double, double, double);
+Vector addvec(Vector, Vector);
+Vector subvec(Vector, Vector);
+Vector mulvec(Vector, double);
+double dotvec(Vector, Vector);
+Vector normvec(Vector);
+double round(double);
+double hypot3(double, double, double);
+void *emalloc(ulong);
--- /dev/null
+++ b/main.c
@@ -1,0 +1,244 @@
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include <draw.h>
+#include <mouse.h>
+#include <keyboard.h>
+#include "dat.h"
+#include "fns.h"
+
+Mousectl *mc;
+Keyboardctl *kc;
+Channel *scrsync;
+Point orig;
+Vector basis;
+Projectile ball;
+double t0, Δt;
+double v0;
+Vector target;
+
+char stats[SLEN][64];
+Image *statc;
+
+void *
+emalloc(ulong n)
+{+ void *p;
+
+ p = malloc(n);
+ if(p == nil)
+ sysfatal("malloc: %r");+ memset(p, 0, n);
+ setmalloctag(p, getcallerpc(&n));
+ return p;
+}
+
+Point
+toscreen(Vector p)
+{+ return addpt(orig, Pt(p.x*basis.x, p.y*basis.y));
+}
+
+Vector
+fromscreen(Point p)
+{+ return Vec((p.x-screen->r.min.x)*M2PIX, (screen->r.max.y-p.y)*M2PIX, 1);
+}
+
+void
+drawstats(void)
+{+ int i;
+
+ snprint(stats[Svel], sizeof(stats[Svel]), "v: %gm/s", hypot(ball.v.x, ball.v.y));
+ snprint(stats[Sdeltax], sizeof(stats[Sdeltax]), "Δx: %gm", target.x-ball.p.x);
+ for(i = 0; i < nelem(stats); i++)
+ stringn(screen, addpt(screen->r.min, Pt(10, font->height*i+1)), statc, ZP, font, stats[i], sizeof(stats[i]));
+}
+
+void
+redraw(void)
+{+ lockdisplay(display);
+ draw(screen, screen->r, display->black, nil, ZP);
+ fillellipse(screen, toscreen(ball.p), 2, 2, display->white, ZP);
+ line(screen, toscreen(Vec(ball.p.x, 0, 1)), toscreen(target), 0, 0, 1, statc, ZP);
+ drawstats();
+ flushimage(display, 1);
+ unlockdisplay(display);
+}
+
+void
+mmb(void)
+{+ enum {+ SETV0,
+ };
+ static char *items[] = {+ [SETV0] "set v0",
+ nil
+ };
+ static Menu menu = { .item = items };+ char buf[32];
+
+ snprint(buf, sizeof(buf), "%g", v0);
+ switch(menuhit(2, mc, &menu, nil)){+ case SETV0:
+ enter("v0(m/s):", buf, sizeof(buf), mc, kc, nil);+ v0 = strtod(buf, 0);
+ break;
+ }
+}
+
+void
+rmb(void)
+{+ enum {+ RST,
+ QUIT,
+ };
+ static char *items[] = {+ [RST] "reset",
+ [QUIT] "quit",
+ nil,
+ };
+ static Menu menu = { .item = items };+
+ switch(menuhit(3, mc, &menu, nil)){+ case RST:
+ ball.p = Vec((2+1)*M2PIX, (2+1)*M2PIX, 1);
+ ball.v = Vec(0, 0, 1);
+ break;
+ case QUIT:
+ threadexitsall(nil);
+ }
+}
+
+void
+mouse(void)
+{+ Vector p;
+ double θ, dist, eta;
+
+ if(ball.p.y <= (2+1)*M2PIX){+ p = subvec(fromscreen(mc->xy), ball.p);
+ θ = atan2(p.y, p.x);
+ snprint(stats[Stheta], sizeof(stats[Stheta]), "θ: %g°", θ*180/PI);
+ dist = v0*v0*sin(2*θ)/Eg;
+ target = Vec(ball.p.x+dist, 0, 1);
+ eta = 2*v0*sin(θ)/Eg;
+ snprint(stats[Seta], sizeof(stats[Seta]), "eta: %gs", eta);
+ if((mc->buttons & 1) != 0)
+ ball.v = Vec(v0*cos(θ), v0*sin(θ), 1);
+ }
+ if((mc->buttons & 2) != 0)
+ mmb();
+ if((mc->buttons & 4) != 0)
+ rmb();
+}
+
+void
+key(Rune r)
+{+ switch(r){+ case Kdel:
+ case 'q':
+ threadexitsall(nil);
+ }
+}
+
+void
+resized(void)
+{+ lockdisplay(display);
+ if(getwindow(display, Refnone) < 0)
+ fprint(2, "can't reattach to window\n");
+ orig = Pt(screen->r.min.x, screen->r.max.y);
+ unlockdisplay(display);
+ redraw();
+}
+
+void
+scrsyncproc(void *)
+{+ for(;;){+ send(scrsync, nil);
+ sleep(SEC/FPS);
+ }
+}
+
+#pragma varargck type "V" Vector;
+int
+Vfmt(Fmt *f)
+{+ Vector v;
+
+ v = va_arg(f->args, Vector);
+ return fmtprint(f, "(%g %g)", v.x, v.y);
+}
+
+void
+usage(void)
+{+ fprint(2, "usage: %s\n", argv0);
+ exits("usage");+}
+
+void
+threadmain(int argc, char *argv[])
+{+ Rune r;
+
+ fmtinstall('V', Vfmt);+ ARGBEGIN{+ default: usage();
+ }ARGEND;
+
+ if(initdraw(nil, nil, "ballistics") < 0)
+ sysfatal("initdraw: %r");+ mc = initmouse(nil, screen);
+ if(mc == nil)
+ sysfatal("initmouse: %r");+ kc = initkeyboard(nil);
+ if(kc == nil)
+ sysfatal("initkeyboard: %r");+ statc = allocimage(display, Rect(0, 0, 1, 1), screen->chan, 1, DYellow);
+ if(statc == nil)
+ sysfatal("allocimage: %r");+ orig = Pt(screen->r.min.x, screen->r.max.y);
+ basis = Vec(PIX2M, -PIX2M, 1);
+ ball.p = Vec((2+1)*M2PIX, (2+1)*M2PIX, 1);
+ ball.v = Vec(0, 0, 1);
+ ball.mass = 106000;
+ v0 = 1640; /* Paris Gun's specs */
+ scrsync = chancreate(1, 0);
+ display->locking = 1;
+ unlockdisplay(display);
+ proccreate(scrsyncproc, 0, STACK);
+ t0 = nsec();
+
+ for(;;){+ Alt a[] = {+ {mc->c, &mc->Mouse, CHANRCV},+ {mc->resizec, nil, CHANRCV},+ {kc->c, &r, CHANRCV},+ {scrsync, nil, CHANRCV},+ {nil, nil, CHANEND}+ };
+ switch(alt(a)){+ case 0: mouse(); break;
+ case 1: resized(); break;
+ case 2: key(r); break;
+ case 3: redraw(); break;
+ }
+ Δt = (nsec()-t0)/1e9;
+ ball.v = addvec(ball.v, mulvec(Vec(0, -Eg, 1), Δt));
+ ball.p = addvec(ball.p, mulvec(ball.v, Δt));
+ snprint(stats[Spos], sizeof(stats[Spos]), "p: %V", ball.p);
+ if(ball.p.y <= (2+1)*M2PIX){+ ball.p.y = (2+1)*M2PIX;
+ ball.v = Vec(0, 0, 1);
+ }
+ t0 += Δt*1e9;
+ }
+}
--- /dev/null
+++ b/matrix.c
@@ -1,0 +1,74 @@
+#include <u.h>
+#include <libc.h>
+#include "dat.h"
+#include "fns.h"
+
+void
+addm(Matrix a, Matrix b)
+{+ int i, j;
+
+ for(i = 0; i < 3; i++)
+ for(j = 0; j < 3; j++)
+ a[i][j] += b[i][j];
+}
+
+void
+subm(Matrix a, Matrix b)
+{+ int i, j;
+
+ for(i = 0; i < 3; i++)
+ for(j = 0; j < 3; j++)
+ a[i][j] -= b[i][j];
+}
+
+void
+mulm(Matrix a, Matrix b)
+{+ int i, j, k;
+ Matrix r;
+
+ for(i = 0; i < 3; i++)
+ for(j = 0; j < 3; j++){+ r[i][j] = 0;
+ for(k = 0; k < 3; k++)
+ r[i][j] += a[i][k]*b[k][j];
+ }
+ for(i = 0; i < 3; i++)
+ for(j = 0; j < 3; j++)
+ a[i][j] = r[i][j];
+}
+
+void
+transm(Matrix m)
+{+ int i, j;
+ double tmp;
+
+ for(i = 0; i < 3; i++)
+ for(j = i; j < 3; j++){+ tmp = m[i][j];
+ m[i][j] = m[j][i];
+ m[j][i] = tmp;
+ }
+}
+
+double
+detm(Matrix m)
+{+ return m[0][0]*(m[1][1]*m[2][2] - m[1][2]*m[2][1])
+ + m[0][1]*(m[1][2]*m[2][0] - m[1][0]*m[2][2])
+ + m[0][2]*(m[1][0]*m[2][1] - m[1][1]*m[2][0]);
+}
+
+Vector
+mulvecm(Vector v, Matrix m)
+{+ Vector r;
+
+ r.x = v.x * m[0][0] + v.y * m[0][1] + v.w * m[0][2];
+ r.y = v.x * m[1][0] + v.y * m[1][1] + v.w * m[1][2];
+ r.w = v.x * m[2][0] + v.y * m[2][1] + v.w * m[2][2];
+ return r;
+}
--- /dev/null
+++ b/mkfile
@@ -1,0 +1,13 @@
+</$objtype/mkfile
+
+BIN=/$objtype/bin/
+TARG=ballistics
+OFILES=\
+ main.$O\
+ util.$O\
+ vector.$O\
+ matrix.$O
+
+HFILES=dat.h fns.h
+
+</sys/src/cmd/mkone
--- /dev/null
+++ b/util.c
@@ -1,0 +1,16 @@
+#include <u.h>
+#include <libc.h>
+#include "dat.h"
+#include "fns.h"
+
+double
+round(double n)
+{+ return floor(n + 0.5);
+}
+
+double
+hypot3(double x, double y, double z)
+{+ return hypot(x, hypot(y, z));
+}
--- /dev/null
+++ b/vector.c
@@ -1,0 +1,48 @@
+#include <u.h>
+#include <libc.h>
+#include "dat.h"
+#include "fns.h"
+
+Vector
+Vec(double x, double y, double w)
+{+ return (Vector){x, y, w};+}
+
+Vector
+addvec(Vector v, Vector u)
+{+ return (Vector){v.x+u.x, v.y+u.y, v.w+u.w};+}
+
+Vector
+subvec(Vector v, Vector u)
+{+ return (Vector){v.x-u.x, v.y-u.y, v.w-u.w};+}
+
+Vector
+mulvec(Vector v, double s)
+{+ return (Vector){v.x*s, v.y*s, v.w*s};+}
+
+double
+dotvec(Vector v, Vector u)
+{+ return v.x*u.x + v.y*u.y + v.w*u.w;
+}
+
+Vector
+normvec(Vector v)
+{+ double len;
+
+ len = hypot3(v.x, v.y, v.w);
+ if(len == 0)
+ return (Vector){0, 0, 0};+ v.x /= len;
+ v.y /= len;
+ v.w /= len;
+ return v;
+}