games/galaxy: Change button 2 to reposition the galaxy, remove "move" from the button 3 menu

sys/man/1/galaxy

@@ -45,15 +45,12 @@ of the body. Holding a button 1-3 chord
 changes the initial velocity of the body. Releasing button 1
 restarts the simulator with the new body in motion. When new
 bodies are created, the simulator maintains the Galilean (inertial)
-reference frame.
+reference frame where the center of mass of the galaxy is at rest.
+.PP
+Mouse button 2 repositions the visible region of the galaxy by dragging.
 .PP
 Mouse button 3 opens a menu with the following options:
 .TP
-.B move
-Change the visible region of the simulation
-by holding button 1 and dragging. Any other mouse
-button restarts the simulation.
-.TP
 .B zoom
 Prompts for a floating point value to change the scale of the
 simulation. E.g. a value of 2 will halve the scale (zoom in)

sys/src/games/galaxy/galaxy.c

@@ -35,8 +35,7 @@ Cursor pausecursor={
 
 enum {
 	STK = 8192,
-	MOVE = 0,
+	ZOOM = 0,
-	ZOOM,
 	SPEED,
 	GRAV,
 	SAVE,
@@ -57,7 +56,7 @@ double
 	LIM = 10,
 	dt²;
 char *file;
-int showv, showa, throttle, moving;
+int showv, showa, throttle;
 
 char *menustr[] = {
 	[SAVE]	"save",
@@ -65,7 +64,6 @@ char *menustr[] = {
 	[ZOOM]	"zoom",
 	[SPEED]	"speed",
 	[GRAV]	"gravity",
-	[MOVE]	"move",
 	[EXIT]	"exit",
 	[MEND]	nil
 };
@@ -313,31 +311,24 @@ getinput(char *info, char *sug)
 }
 
 void
-move(void)
+domove(void)
 {
-	Point od;
+	Point oldp, off;
+
 	setcursor(mc, &crosscursor);
+	pause(0, 0);
+	oldp = mc->xy;
 	for(;;) {
-		for(;;) {
+		readmouse(mc);
-			readmouse(mc);
+		if(mc->buttons != 2)
-			if(mc->buttons & 1)
+			break;
-				break;
+		off = subpt(mc->xy, oldp);
-			if(mc->buttons & 4) {
+		oldp = mc->xy;
-				moving = 0;
+		orig = addpt(orig, off);
-				setcursor(mc, cursor);
+		drawglxy();
-				return;
-			}
-		}
-		moving = 1;
-		od = subpt(orig, mc->xy);
-		for(;;) {
-			readmouse(mc);
-			if(!(mc->buttons & 1))
-				break;
-			orig = addpt(od, mc->xy);
-			drawglxy();
-		}
 	}
+	setcursor(mc, cursor);
+	pause(1, 0);
 }
 
 void
@@ -413,9 +404,6 @@ domenu(void)
 			break;
 		G *= z;
 		break;
-	case MOVE:
-		move();
-		break;
 	case EXIT:
 		threadexitsall(nil);
 		break;
@@ -434,6 +422,9 @@ mousethread(void*)
 		case 1:
 			dobody();
 			break;
+		case 2:
+			domove();
+			break;
 		case 4:
 			domenu();
 			break;
@@ -488,8 +479,6 @@ kbdthread(void*)
 			showa ^= 1;
 			break;
 		case ' ':
-			if(moving)
-				break;
 			paused ^= 1;
 			if(paused) {
 				cursor = &pausecursor;
@@ -537,7 +526,7 @@ Again:
 			b->a.y = b->newa.y;
 			b->newa.x = b->newa.y = 0;
 			STATS(calcs = 0;)
-			quadcalc(space, b, LIM);
+			quadcalc(b, space, LIM);
 			STATS(avgcalcs += calcs;)
 		}
 		STATS(avgcalcs /= glxy.l;)

sys/src/games/galaxy/galaxy.h

@@ -64,7 +64,7 @@ void readglxy(int);
 void writeglxy(int);
 int Bfmt(Fmt*);
 
-void quadcalc(QB, Body*, double);
+void quadcalc(Body*, QB, double);
 int quadins(Body*, double);
 void growquads(void);
 void quadsinit(void);

sys/src/games/galaxy/mkgalaxy.c

@@ -12,7 +12,7 @@ double
 	av, avrand;
 int new, c = 1;
 
-void quadcalc(QB, Body*, double){}
+void quadcalc(Body*, QB, double){}
 Image *randcol(void){ return nil; }
 
 void

sys/src/games/galaxy/quad.c

@@ -84,7 +84,7 @@ quadins(Body *nb, double size)
 }
 
 void
-quadcalc(QB qb, Body *b, double size)
+quadcalc(Body *b, QB qb, double size)
 {
 	double fx÷❨m₁m₂❩, fy÷❨m₁m₂❩, dx, dy, h, G÷h³;
 
@@ -121,9 +121,9 @@ quadcalc(QB qb, Body *b, double size)
 			return;
 		}
 		size /= 2;
-		quadcalc(qb.q->c[0], b, size);
+		quadcalc(b, qb.q->c[0], size);
-		quadcalc(qb.q->c[1], b, size);
+		quadcalc(b, qb.q->c[1], size);
-		quadcalc(qb.q->c[2], b, size);
+		quadcalc(b, qb.q->c[2], size);
 		qb = qb.q->c[3];
 		break;	/* quadcalc(q->q[3], b, size); */
 	}