fix the qball.

5 files changed, 24 insertions, 30 deletions

diff --git a/dat.h b/dat.h
index 5c9b45b..bad9c4d 100644
--- a/dat.h
+++ b/dat.h
@@ -28,5 +28,6 @@ enum {
 	Scambx, Scamby, Scambz,
 	Sfps,
 	Sframes,
+	Sorient,
 	Se
 };
diff --git a/fns.h b/fns.h
index d89bef9..a506140 100644
--- a/fns.h
+++ b/fns.h
@@ -2,4 +2,4 @@ void *emalloc(ulong);
 void *erealloc(void*, ulong);
 Image *eallocimage(Display*, Rectangle, ulong, int, ulong);
 Memimage *eallocmemimage(Rectangle, ulong);
-void qb(Rectangle, Point, Point, Quaternion*, Quaternion*);
+void qball(Rectangle, Point, Point, Quaternion*, Quaternion*);
diff --git a/mkfile b/mkfile
index 2c9c8d7..2761b48 100644
--- a/mkfile
+++ b/mkfile
@@ -7,7 +7,7 @@ TARG=\
 
 OFILES=\
 	alloc.$O\
-	qb.$O\
+	qball.$O\
 
 HFILES=dat.h fns.h
 
diff --git a/qb.c b/qball.c
index 1485b9a..9248f5f 100644
--- a/qb.c
+++ b/qball.c
@@ -15,11 +15,7 @@
 #include "libgraphics/graphics.h"
 #include "fns.h"
 
-static int
-min(int a, int b)
-{
-	return a < b? a: b;
-}
+#define MIN(a, b)	((a)<(b)?(a):(b))
 
 /*
  * Convert a mouse point into a unit quaternion, flattening if
@@ -32,14 +28,13 @@ mouseq(Point2 p, Quaternion *axis)
 	Quaternion q;
 	double rsq = p.x*p.x + p.y*p.y;	/* quadrance */
 
+	q.r = 0;
 	if(rsq > 1){	/* outside the sphere */
-		rsq = sqrt(rsq);
-		q.r = 0;
-		q.i = p.x/rsq;
-		q.j = p.y/rsq;
+		rsq = 1/sqrt(rsq);
+		q.i = p.x*rsq;
+		q.j = p.y*rsq;
 		q.k = 0;
-	}else{		/* within the sphere */
-		q.r = 0;
+	}else{
 		q.i = p.x;
 		q.j = p.y;
 		q.k = sqrt(1 - rsq);
@@ -62,25 +57,24 @@ mouseq(Point2 p, Quaternion *axis)
 }
 
 void
-qb(Rectangle r, Point p0, Point p1, Quaternion *orient, Quaternion *axis)
+qball(Rectangle r, Point p0, Point p1, Quaternion *orient, Quaternion *axis)
 {
-	Quaternion q, down;
+	Quaternion qdown, qdrag;
 	Point2 rmin, rmax;
-	Point2 s0, s1;	/* screen coords */
 	Point2 v0, v1;	/* unit sphere coords */
 	Point2 ctlcen;	/* controller center */
 	double ctlrad;	/* controller radius */
 
+	if(orient == nil)
+		return;
+
 	rmin = Vec2(r.min.x, r.min.y);
 	rmax = Vec2(r.max.x, r.max.y);
-	s0 = Vec2(p0.x, p0.y);
-	s1 = Vec2(p1.x, p1.y);
 	ctlcen = divpt2(addpt2(rmin, rmax), 2);
-	ctlrad = min(Dx(r), Dy(r));
-	v0 = divpt2(subpt2(s0, ctlcen), ctlrad);
-	down = invq(mouseq(v0, axis));
-
-	q = *orient;
-	v1 = divpt2(subpt2(s1, ctlcen), ctlrad);
-	*orient = mulq(q, mulq(down, mouseq(v1, axis)));
+	ctlrad = MIN(Dx(r)/2, Dy(r)/2);
+	v0 = divpt2(Vec2(p0.x-ctlcen.x, ctlcen.y-p0.y), ctlrad);
+	v1 = divpt2(Vec2(p1.x-ctlcen.x, ctlcen.y-p1.y), ctlrad);
+	qdown = mouseq(v0, axis);
+	qdrag = mulq(mouseq(v1, axis), qdown);
+	*orient = mulq(qdrag, *orient);
 }
diff --git a/vis.c b/vis.c
index 96879eb..5796b32 100644
--- a/vis.c
+++ b/vis.c
@@ -50,6 +50,7 @@ Shadertab *shader;
 Model *model;
 Entity *subject;
 Scene *scene;
+Mouse om;
 Quaternion orient = {1,0,0,0};
 
 Camera cams[4], *maincam;
@@ -452,6 +453,7 @@ drawstats(void)
 	snprint(stats[Scambz], sizeof(stats[Scambz]), "bz %V", maincam->bz);
 	snprint(stats[Sfps], sizeof(stats[Sfps]), "FPS %.0f/%.0f/%.0f/%.0f", !maincam->stats.max? 0: 1e9/maincam->stats.max, !maincam->stats.avg? 0: 1e9/maincam->stats.avg, !maincam->stats.min? 0: 1e9/maincam->stats.min, !maincam->stats.v? 0: 1e9/maincam->stats.v);
 	snprint(stats[Sframes], sizeof(stats[Sframes]), "frame %llud", maincam->stats.nframes);
+	snprint(stats[Sorient], sizeof(stats[Sorient]), "ℍ %V", (Point3)orient);
 	for(i = 0; i < Se; i++)
 		stringbg(screen, addpt(screen->r.min, Pt(10,10 + i*font->height)), display->black, ZP, font, stats[i], display->white, ZP);
 }
@@ -518,12 +520,8 @@ drawproc(void *)
 void
 lmb(void)
 {
-	static Mouse om;
-
 	if((om.buttons^mctl->buttons) == 0)
-		qb(screen->r, om.xy, mctl->xy, &orient, nil);
-
-	om = mctl->Mouse;
+		qball(screen->r, om.xy, mctl->xy, &orient, nil);
 }
 
 void
@@ -602,6 +600,7 @@ mouse(void)
 		zoomin();
 	if((mctl->buttons & 16) != 0)
 		zoomout();
+	om = mctl->Mouse;
 }
 
 void