shithub: riscv

--- a/sys/man/1/games

+++ b/sys/man/1/games

@@ -287,6 +287,19 @@

 Once the game has been completed, a message pops up with how long it took to win.

 Use the button 3 menu to choose a mode, or click to play again.

.TP

+.B mole

+A molecular dynamics simulation based on the Lennard-Jones potential.

+.L r

+restarts the simulation.

+.L f

+redraws the screen.

+.L R

+reverses the simulation.

+.L q

+and

+.L Del

+quit the simulation.

+.TP

 .B sokoban

 Guide Glenda through a room full of walls, pebbles and holes to put

 the pebbles in.  Your goal is to arrange all pebbles into holes by

--- a/sys/src/games/mole.c

+++ b/sys/src/games/mole.c

@@ -3,8 +3,14 @@

 #include <draw.h>

 #include <event.h>

-int N = 20, refresh = 0;

+enum {

+	Kdel = 0x7f

+};

+int N = 49,

+	pathlen = 1000,

+	nosnake;

 double dt = 0.01,

 	xmin = -40,

 	xmax = 40,

@@ -11,7 +17,7 @@

 	ymin = -40,

 	ymax = 40,

 	v0 = 0.1;

 #define mini(a,b) (((a)<(b))?(a):(b))

 typedef struct Particle Particle;

@@ -23,6 +29,11 @@

 	Image* col;

};

+typedef struct Path Path;

+struct Path {

+	int *x, *y;

+};

 int colors[] = {

               DBlack,

               DRed,

@@ -47,8 +58,9 @@

               DPurpleblue

};

-Particle *A, *B;

-Particle *prev, *cur;

+Particle	*A, *B;

+Particle	*prev, *cur;

+Path		*paths;

 void

 reset(void)

@@ -70,10 +82,46 @@

 void

+reverse(void)

+{

+	Particle *p, *q;

+	Path *pa;

+	int i;

+	draw(screen, screen->r, display->white, 0, ZP);

+	for(i=0;i<N;i++){

+		pa=paths+i;

+		memset(pa->x, 0, sizeof(int) * pathlen);

+		memset(pa->y, 0, sizeof(int) * pathlen);

+		p=prev+i;

+		q=cur+i;

+		p->vx = -q->vx;

+		p->vy = -q->vy;

+		p->prevx = p->x;

+		p->prevy = p->y;

+		p->x = q->x;

+		p->y = q->y;

+	}

+}

+void

+drawpath(Path *p, Image *col, int i)

+{

+	int j;

+	if((j = i+1) == pathlen)

+		j = 0;

+	draw(screen, Rect(p->x[i], p->y[i], p->x[i]+1, p->y[i]+1), col, 0, ZP);

+	if(nosnake)

+		return;

+	draw(screen, Rect(p->x[j], p->y[j], p->x[j]+1, p->y[j]+1), display->white, 0, ZP);

+}

+void

 usage(void)

 	print("USAGE: mole options\n");

-	print(" -N number of particles [20]\n");

+	print(" -N number of particles [49]\n");

 	print(" -x left boundary [-40]\n");

 	print(" -X right boundary [40]\n");

 	print(" -y top boundary [-40]\n");

@@ -80,7 +128,7 @@

 	print(" -Y bottom boundary [40]\n");

 	print(" -t time step [0.01]\n");

 	print(" -v maximum start velocity [0.1]\n");

-	print(" -F clear every <n> frames (0:off) [0]\n");

+	print(" -P path length [1000]\n");

 	exits("usage");

@@ -89,6 +137,7 @@

 	int i, j;

 	Particle *p, *q;

+	Path *pa;

 	double dx, dx1, dx2, dy, dy1, dy2, R, F;

 	char* f;

@@ -95,7 +144,7 @@

 	#define FARG(c, v) case c: if(!(f=ARGF())) usage(); v = atof(f); break;

 	ARGBEGIN {

 	case 'N': if(!(f=ARGF())) usage(); N = atoi(f); break;

-	case 'F': if(!(f=ARGF())) usage(); refresh = atoi(f); break;

+	case 'P': if(!(f=ARGF())) usage(); pathlen = atoi(f); break;

 	FARG('v', v0);

 	FARG('x', xmin);

 	FARG('X', xmax);

@@ -105,8 +154,17 @@

 	default: usage();

 	} ARGEND;

+	if(pathlen == 0) {

+		nosnake = 1;

+		pathlen = 1000;

+	}

 	A = calloc(sizeof(Particle), N);

 	B = calloc(sizeof(Particle), N);

+	paths = calloc(sizeof(Path), N);

+	for(pa=paths;pa<paths+N;pa++){

+		pa->x = calloc(sizeof(int), pathlen);

+		pa->y = calloc(sizeof(int), pathlen);

+	}

 	prev = A;

 	cur = B;

 	srand(time(0));

@@ -114,9 +172,9 @@

 	einit(Emouse | Ekeyboard);

 	reset();

-	i=0;

-	while(1) {

-		if(refresh && ((++i)%refresh)==0) draw(screen, screen->r, display->white, 0, ZP);

+	for(i=0;; i++) {

+		if(i == pathlen)

+			i = 0;

 		memset(cur, 0, sizeof(Particle) * N);

 		for(p=prev;p<prev+N;p++) {

 			for(q=prev;q<p;q++) {

@@ -148,7 +206,7 @@

 		for(j=0;j<N;j++) {

-			int x, y;

+			pa = paths+j;

 			p = prev+j;

 			q = cur+j;

 			q->x = 2*p->x - p->prevx + q->ax * dt*dt;

@@ -162,9 +220,9 @@

 			if(q->y > ymax) {q->y -= ymax - ymin; q->prevy -= ymax - ymin;}

 			if(q->y < ymin) {q->y += ymax - ymin; q->prevy += ymax - ymin;}

 			q->col = p->col;

-			x = (screen->r.max.x - screen->r.min.x) * (q->x - xmin) / (xmax - xmin) + screen->r.min.x;

-			y = (screen->r.max.y - screen->r.min.y) * (q->y - ymin) / (ymax - ymin) + screen->r.min.y;

-			draw(screen, Rect(x, y, x+1, y+1), p->col, 0, ZP);

+			pa->x[i] = (screen->r.max.x - screen->r.min.x) * (q->x - xmin) / (xmax - xmin) + screen->r.min.x;

+			pa->y[i] = (screen->r.max.y - screen->r.min.y) * (q->y - ymin) / (ymax - ymin) + screen->r.min.y;

+			drawpath(pa, p->col, i);

 		Particle* tmp = prev;

@@ -175,8 +233,9 @@

 		if(ecankbd()) {

 			switch(ekbd()) {

-				case 'q': exits(0); break;

+				case 'q': case Kdel: exits(0); break;

 				case 'r': reset(); break;

+				case 'R': reverse(); break;

 				case 'f': draw(screen, screen->r, display->white, 0, ZP); break;