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-rw-r--r--balls.c202
1 files changed, 107 insertions, 95 deletions
diff --git a/balls.c b/balls.c
index a26605d..ccc3e8e 100644
--- a/balls.c
+++ b/balls.c
@@ -1,10 +1,8 @@
-#include <u.h>
-#include <libc.h>
+#include "balls.h"
+
#include <stdio.h>
-#include <draw.h>
#include <thread.h>
#include <mouse.h>
-#include <cursor.h>
#include <keyboard.h>
#define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))
@@ -19,10 +17,10 @@ enum {
KEY_QUIT = 'q' ,
- NBALLS = 2,
- RADIUS = 20,
+ NBALLS = 3,
VMAX = 5,
G = 1,
+ MASS = 1,
FPS = 60,
NS_PER_SEC = 1000000000,
@@ -33,14 +31,14 @@ enum {
};
typedef struct {
- Point pos;
- int vx, vy;
- int col;
+ Ball b;
+
+ int color;
Channel *frametick;
- Channel **posin; /* receive positions of other balls */
- Channel **posout; /* send position to other balls */
+ Channel **in; /* <-chan Ball */
+ Channel **out; /* chan<- Ball */
int nothers; /* number of other balls */
} BallArg;
@@ -57,8 +55,6 @@ void vcopyskip(Channel *dst[], Channel *src[], int n, int skip);
void nooverlapcircles(Point centers[], int n);
Point randptinrect(Rectangle r);
int randint(int lo, int hi);
-int isoverlapcircle(Point p, Point q);
-int dist(Point p, Point q);
void ball(void *arg);
Image *alloccircle(int fg, int bg);
void drawcircle(Image *m, Point pos);
@@ -137,61 +133,75 @@ drawbg(Image *walls, Image *bg) {
void
spawnballs(int n) {
Channel **ticks;
- Point *pos;
+ Point *ps;
int i, j;
- BallArg *b;
- Channel ***poschans;
+ BallArg *arg;
+ Channel ***cs;
if ((ticks = allocchans(n, sizeof(int), TICK_BUFSIZE)) == nil)
sysfatal("failed to allocate frame ticker channels");
threadcreate(frametick, ticks, mainstacksize);
- if ((pos = malloc(n*sizeof(Point))) == nil)
+ if ((ps = malloc(n*sizeof(Point))) == nil)
sysfatal("failed to allocate position array");
- nooverlapcircles(pos, n);
+ nooverlapcircles(ps, n);
- if ((poschans = malloc(n*sizeof(Channel **))) == nil)
- sysfatal("failed to allocate position channel matrix");
+ if ((cs = malloc(n*sizeof(Channel **))) == nil)
+ sysfatal("failed to allocate channel matrix");
for (i = 0; i < n; i++) {
- if ((poschans[i] = malloc(n*sizeof(Channel *))) == nil)
- sysfatal("failed to allocate row of position channel matrix");
+ if ((cs[i] = malloc(n*sizeof(Channel *))) == nil)
+ sysfatal("failed to allocate row of channel matrix");
for (j = 0; j < n; j++) {
if (j == i)
continue;
- if ((poschans[i][j] = chancreate(sizeof(Point), POS_BUFSIZE)) == nil)
- sysfatal("failed to create position channel");
+ if ((cs[i][j] = chancreate(sizeof(Ball), POS_BUFSIZE)) == nil)
+ sysfatal("failed to create channel");
}
}
for (i = 0; i < n; i++) {
- if ((b = malloc(sizeof(BallArg))) == nil)
+ for (j = 0; j < n; j++)
+ printf("%16p ", cs[i][j]);
+ printf("\n\n");
+ }
+
+ for (i = 0; i < n; i++) {
+ if ((arg = malloc(sizeof(BallArg))) == nil)
sysfatal("failed to allocate ball");
- b->pos = pos[i];
- b->vx = randint(-VMAX, VMAX+1);
- b->vy = randint(-VMAX, VMAX+1);
- b->col = ballcolors[randint(0, NELEMS(ballcolors))];
+ arg->b.p = ps[i];
+ arg->b.v = V(randint(-VMAX, VMAX+1), randint(-VMAX, VMAX+1));
+ arg->b.m = MASS;
- b->frametick = ticks[i];
+ arg->color = ballcolors[randint(0, NELEMS(ballcolors))];
- if ((b->posin = malloc((n-1)*sizeof(Channel *))) == nil)
- sysfatal("failed to allocate array of incoming position channels");
- mcopycolskip(b->posin, poschans, n, i, i);
+ arg->frametick = ticks[i];
- if ((b->posout = malloc((n-1)*sizeof(Channel *))) == nil)
- sysfatal("failed to allocate array of outgoing position channels");
- vcopyskip(b->posout, poschans[i], n, i);
+ if ((arg->in = malloc((n-1)*sizeof(Channel *))) == nil)
+ sysfatal("failed to allocate array of incoming channels");
+ mcopycolskip(arg->in, cs, n, i, i);
+ printf("%d in:\n", i);
+ for (j = 0; j < n-1; j++)
+ printf("%16p ", arg->in[j]);
+ printf("\n");
- b->nothers = n-1;
+ if ((arg->out = malloc((n-1)*sizeof(Channel *))) == nil)
+ sysfatal("failed to allocate array of outgoing channels");
+ vcopyskip(arg->out, cs[i], n, i);
+ printf("%d: out\n", i);
+ for (j = 0; j < n-1; j++)
+ printf("%16p ", arg->out[j]);
+ printf("\n\n");
+ arg->nothers = n-1;
- threadcreate(ball, b, mainstacksize);
+ threadcreate(ball, arg, mainstacksize);
}
- free(pos);
+ free(ps);
for (i = 0; i < n; i++)
- free(poschans[i]);
- free(poschans);
+ free(cs[i]);
+ free(cs);
}
Channel **
@@ -230,8 +240,12 @@ mcopycolskip(Channel *vec[], Channel **matrix[], int n, int col, int skip) {
/* copy each element in n-length src, except for element skip, into n-1 length dst */
void
vcopyskip(Channel *dst[], Channel *src[], int n, int skip) {
- memmove(dst, src, skip*sizeof(Channel *));
- memmove(dst, src+skip+1, (n-skip-1)*sizeof(Channel *));
+ int i;
+
+ for (i = 0; i < skip; i++)
+ dst[i] = src[i];
+ for (i = skip+1; i < n; i++)
+ dst[i-1] = src[i];
}
void
@@ -242,7 +256,7 @@ nooverlapcircles(Point centers[], int n) {
for (i = 0; i < n; i++) {
centers[i] = randptinrect(insetrect(bounds, RADIUS));
for (j = 0; j < i; j++)
- if (isoverlapcircle(centers[j], centers[i]))
+ if (iscollision(centers[j], centers[i]))
break;
if (j < i) { /* overlapping */
i--;
@@ -261,74 +275,71 @@ randint(int lo, int hi) {
return (rand() % (hi-lo)) + lo;
}
-int
-isoverlapcircle(Point p, Point q) {
- return dist(p, q) < 2*RADIUS;
-}
-
-int
-dist(Point p, Point q) {
- Rectangle r;
-
- r = Rpt(p, q);
- return sqrt(Dx(r)*Dx(r) + Dy(r)*Dy(r));
-}
-
void
ball(void *arg) {
- BallArg *b;
- Point p1, p2;
+ BallArg *barg;
+ Point p, oldp;
+ Vec v;
+ int m;
Image *fill, *erase;
- int t, i, vsum;
- float rx, ry;
- Point otherpos, vdir;
-
- b = (BallArg *) arg;
- p1 = p2 = b->pos;
-
- fill = alloccircle(b->col, DTransparent);
+ int i;
+ Ball other;
+ Point midpoint;
+ Vec d, n;
+ int magnitude;
+ int t;
+
+ barg = (BallArg *) arg;
+ p = oldp = barg->b.p;
+ v = barg->b.v;
+ m = barg->b.m;
+
+ fill = alloccircle(barg->color, DTransparent);
erase = alloccircle(BG, DTransparent);
if (fill == nil ||erase == nil)
sysfatal("failed to allocate image");
for (;;) {
- b->vy += G;
+ v.y += G;
- p2.x += b->vx;
- p2.y += b->vy;
+ p = ptaddv(p, v);
- printf("(%d,%d) %d %d\n", b->pos.x, b->pos.y, b->vx, b->vy);
+ printf("(%d,%d) %d %d\n", p.x, p.y, v.x, v.y);
/* check for wall collision */
- if (p2.x < bounds.min.x+RADIUS || p2.x > bounds.max.x-RADIUS) {
- p2.x = clamp(p2.x, bounds.min.x+RADIUS, bounds.max.x-RADIUS);
- printf("clamped to %d\n", b->pos.x);
- b->vx = -b->vx;
+ if (p.x < bounds.min.x+RADIUS || p.x > bounds.max.x-RADIUS) {
+ p.x = clamp(p.x, bounds.min.x+RADIUS, bounds.max.x-RADIUS);
+ printf("clamped to %d\n", p.x);
+ v.x = -v.x;
}
- if (p2.y < bounds.min.y+RADIUS || p2.y > bounds.max.y-RADIUS) {
- p2.y = clamp(p2.y, bounds.min.y+RADIUS, bounds.max.y-RADIUS);
- b->vy = -b->vy;
+ if (p.y < bounds.min.y+RADIUS || p.y > bounds.max.y-RADIUS) {
+ p.y = clamp(p.y, bounds.min.y+RADIUS, bounds.max.y-RADIUS);
+ v.y = -v.y;
}
- broadcast(p2, b->posout, b->nothers);
+ broadcast(p, barg->out, barg->nothers);
/* check for ball collision */
- for (i = 0; i < b->nothers; i++) {
- recv(b->posin[i], &otherpos);
- if (isoverlapcircle(p2, otherpos)) {
- vdir = subpt(p2, otherpos);
- rx = (float) vdir.x / (float) (vdir.x + vdir.y);
- ry = (float) vdir.y / (float) (vdir.x + vdir.y);
- vsum = b->vx + b->vy;
- b->vx = rx * (float) vsum;
- b->vy = ry * (float) vsum;
+ for (i = 0; i < barg->nothers; i++) {
+ printf("recv %16p\n", barg->in[i]);
+ recv(barg->in[i], &other);
+ if (iscollision(p, other.p)) {
+ midpoint = divpt(addpt(p, other.p), 2);
+ d = Vpt(p, other.p);
+ p = ptaddv(midpoint, vmuls(unitnorm(d), -RADIUS));
+
+ n = unitnorm(Vpt(other.p, p));
+ magnitude = 2*vdot(v, n) / (m + other.m);
+ v = vsub(v, vmuls(
+ vsub(vmuls(n, m), vmuls(n, other.m)),
+ magnitude));
}
}
-
- recv(b->frametick, &t);
- drawcircle(erase, p1);
- drawcircle(fill, p2);
- p1 = p2;
+
+ recv(barg->frametick, &t);
+ drawcircle(erase, oldp);
+ drawcircle(fill, p);
+ oldp = p;
}
}
@@ -352,7 +363,6 @@ alloccircle(int fg, int bg) {
return m;
}
-
void
drawcircle(Image *m, Point pos) {
draw(screen, rectaddpt(bounds, subpt(pos, Pt(RADIUS, RADIUS))), m, nil, ZP);
@@ -375,8 +385,10 @@ max(int a, int b) {
void
broadcast(Point p, Channel *cs[], int n) {
- while (n-- > 0)
+ while (n-- > 0) {
+ printf("send %16p\n", cs[n]);
send(cs[n], &p);
+ }
}
void
generated by cgit v1.2.3 (git 2.25.1) at 2026-03-15 23:09:34 +0000