WebSVN – gelsvn – Diff – /trunk/src/GLGraphics/QuatTrackBall.cpp


#include <iostream>
#include "CGLA/CGLA.h"
#include "QuatTrackBall.h"
 
#include "gel_glu.h"
#include "GLViewController.h"
 
 
using namespace std;
using namespace CGLA;
 
namespace GLGraphics
{
    
    QuatTrackBall::QuatTrackBall(const Vec3f& _centre, 
			 float _eye_dist,
			 unsigned _width, 
			 unsigned _height):
	centre(_centre), width(_width), height(_height), 
	scale(0.5*_eye_dist), eye_dist(_eye_dist)
	{
	// This size should really be based on the distance from the center of
	// rotation to the point on the object underneath the mouse.  That
	// point would then track the mouse as closely as possible.  This is a
	// simple example, though, so that is left as an exercise.
	ballsize = 2.0f;
	screen_centre = Vec2i(width/2, height/2);
	qrot = Quaternion(0.0, 0.0, 0.0, 1.0);
	qinc = Quaternion(0.0, 0.0, 0.0, 1.0);
	trans = Vec2f(0.0, 0.0);
    }
    
    void QuatTrackBall::grab_ball(TrackBallAction act, const Vec2i& v)
    {
	set_position(scalePoint(v));
	current_action = act;
    }
    
    void QuatTrackBall::roll_ball(const Vec2i& v)
    {
	Vec2f w = scalePoint(v); 
	
	switch (current_action) 
	{
			case ROTATE_ACTION:
	    rotate(w);
	    break;
	    
			case PAN_ACTION:
	    pan(w);
	    break;
	    
			case ZOOM_ACTION:
	    zoom(w);
	    break;
	}
	last_pos = w;	
    }
    
    // Call this when the user does a mouse down.  
    // Stop the trackball glide, then remember the mouse
    // down point (for a future rotate, pan or zoom).
    void QuatTrackBall::set_position(const Vec2f& _last_pos) 
    {
	stop_spin();
	last_pos = _last_pos;
    }
    
    // Rotationaly spin the trackball by the current increment.
    // Use this to implement rotational glide.
    void QuatTrackBall::do_spin() 
    {
	qrot = qrot*qinc;
    }
    
    // Cease any rotational glide by zeroing the increment.
    void QuatTrackBall::stop_spin() 
    {
	qinc.set(0.0, 0.0, 0.0, 1.0);
    }
    
    void QuatTrackBall::rotate(const Vec2f& new_v) 
    {
	calcRotation(new_v);
	do_spin();	
    }
    
    void QuatTrackBall::pan(const Vec2f& new_v) 
    {
	trans += (new_v - last_pos) * Vec2f(scale[0], scale[1]);
    }
    
    void QuatTrackBall::zoom(const Vec2f& new_v) 
    {
	eye_dist += (new_v[1] - last_pos[1]) * scale[2];
	eye_dist = max(eye_dist, 0.01f);
    }
    
    void QuatTrackBall::calcRotation(const Vec2f& new_pos) 
    {
	// Check for zero rotation
	if (new_pos == last_pos) 
	    qinc = Quaternion();
	else
	{
		// Form two vectors based on input points, find rotation axis
		Vec3f p1 = Vec3f(new_pos[0], new_pos[1], projectToSphere(new_pos));
		Vec3f p2 = Vec3f(last_pos[0], last_pos[1], projectToSphere(last_pos));
		
		Vec3f q = cross(p1, p2);		/* axis of rotation from p1 and p2 */
		float L = sqrt(1.0f-dot(q,q) / (dot(p1,p1) * dot(p2,p2)));
		
		q.normalize();				/* q' = axis of rotation */
		q *= sqrt((1 - L)/2);	/* q' = q' * sin(phi) */
		
		qinc.set(q[0],q[1],q[2],sqrt((1 + L)/2));
	    }
    }
    
    // Project an x,y pair onto a sphere of radius r OR a hyperbolic sheet
    // if we are away from the center of the sphere.
    float QuatTrackBall::projectToSphere(const Vec2f& v) 
    {
	float d, t, z;
	
	d = v.length();
	
	// Inside sphere 
	if (d < ballsize * 0.70710678118654752440) {   
	    z = sqrt(ballsize*ballsize - d*d);
	}
	// On hyperbola 
	else {           
	    t = ballsize / 1.41421356237309504880;
	    z = t*t / d;
	}
	
	return z;
    }
    
    // Scales integer point to the range [-1, 1]
    Vec2f QuatTrackBall::scalePoint(const Vec2i& v) const
    {
	Vec2f w(v[0],height - v[1]);
	w -= Vec2f(screen_centre);
	w /= Vec2f(width,height);
	w = CGLA::v_min(Vec2f(1.0f), CGLA::v_max(Vec2f(-1), 2*w));
	return w; 
    }
    
    void QuatTrackBall::get_view_param(Vec3f& eye, Vec3f& _centre, Vec3f& up) const
    {
	up  = qrot.apply(Vec3f(0,1,0));
	Vec3f right = qrot.apply(Vec3f(1,0,0));
	_centre = centre - up * trans[1] - right * trans[0]; 
	eye = qrot.apply(Vec3f(0,0,1)*eye_dist) + _centre;
    }
    
    
    // Modify the current gl matrix by the trackball rotation and translation.
    void QuatTrackBall::set_gl_modelview() const
    {
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	Vec3f eye;
	Vec3f _centre;
	Vec3f up;
	get_view_param(eye, _centre, up);
	gluLookAt(eye[0], eye[1], eye[2],
		  _centre[0], _centre[1], _centre[2], 
		  up[0],up[1],up[2]);
    }
    
    bool QuatTrackBall::is_spinning() const
    {
	static const Quaternion null_quat(0,0,0,1);
	if(!(qinc == null_quat))
	    return true;
	return false;
    }
}
 

Rev 152	Rev 178
1	`#include <iostream>`	1	`#include <iostream>`
2	`#include "CGLA/CGLA.h"`	2	`#include "CGLA/CGLA.h"`
3	`#include "QuatTrackBall.h"`	3	`#include "QuatTrackBall.h"`
4		4
5	`#include "gel_glu.h"`	5	`#include "gel_glu.h"`
6	`#include "GLViewController.h"`	6	`#include "GLViewController.h"`
7		7
8		8
9	`using namespace std;`	9	`using namespace std;`
10	`using namespace CGLA;`	10	`using namespace CGLA;`
11		11
12	`namespace GLGraphics`	12	`namespace GLGraphics`
13	`{`	13	`{`
14		14
15	`QuatTrackBall::QuatTrackBall(const Vec3f& _centre,`	15	`QuatTrackBall::QuatTrackBall(const Vec3f& _centre,`
16	`float _eye_dist,`	16	`float _eye_dist,`
17	`unsigned _width,`	17	`unsigned _width,`
18	`unsigned _height):`	18	`unsigned _height):`
19	`centre(_centre), width(_width), height(_height),`	19	`centre(_centre), width(_width), height(_height),`
20	`scale(0.5*_eye_dist), eye_dist(_eye_dist)`	20	`scale(0.5*_eye_dist), eye_dist(_eye_dist)`
21	`{`	21	`{`
22	`// This size should really be based on the distance from the center of`	22	`// This size should really be based on the distance from the center of`
23	`// rotation to the point on the object underneath the mouse. That`	23	`// rotation to the point on the object underneath the mouse. That`
24	`// point would then track the mouse as closely as possible. This is a`	24	`// point would then track the mouse as closely as possible. This is a`
25	`// simple example, though, so that is left as an exercise.`	25	`// simple example, though, so that is left as an exercise.`
26	`ballsize = 2.0f;`	26	`ballsize = 2.0f;`
27	`screen_centre = Vec2i(width/2, height/2);`	27	`screen_centre = Vec2i(width/2, height/2);`
28	`qrot = Quaternion(0.0, 0.0, 0.0, 1.0);`	28	`qrot = Quaternion(0.0, 0.0, 0.0, 1.0);`
29	`qinc = Quaternion(0.0, 0.0, 0.0, 1.0);`	29	`qinc = Quaternion(0.0, 0.0, 0.0, 1.0);`
30	`trans = Vec2f(0.0, 0.0);`	30	`trans = Vec2f(0.0, 0.0);`
31	`}`	31	`}`
32		32
33	`void QuatTrackBall::grab_ball(TrackBallAction act, const Vec2i& v)`	33	`void QuatTrackBall::grab_ball(TrackBallAction act, const Vec2i& v)`
34	`{`	34	`{`
35	`set_position(scalePoint(v));`	35	`set_position(scalePoint(v));`
36	`current_action = act;`	36	`current_action = act;`
37	`}`	37	`}`
38		38
39	`void QuatTrackBall::roll_ball(const Vec2i& v)`	39	`void QuatTrackBall::roll_ball(const Vec2i& v)`
40	`{`	40	`{`
41	`Vec2f w = scalePoint(v);`	41	`Vec2f w = scalePoint(v);`
42		42
43	`switch (current_action)`	43	`switch (current_action)`
44	`{`	44	`{`
45	`case ROTATE_ACTION:`	45	`case ROTATE_ACTION:`
46	`rotate(w);`	46	`rotate(w);`
47	`break;`	47	`break;`
48		48
49	`case PAN_ACTION:`	49	`case PAN_ACTION:`
50	`pan(w);`	50	`pan(w);`
51	`break;`	51	`break;`
52		52
53	`case ZOOM_ACTION:`	53	`case ZOOM_ACTION:`
54	`zoom(w);`	54	`zoom(w);`
55	`break;`	55	`break;`
56	`}`	56	`}`
57	`last_pos = w;`	57	`last_pos = w;`
58	`}`	58	`}`
59		59
60	`// Call this when the user does a mouse down.`	60	`// Call this when the user does a mouse down.`
61	`// Stop the trackball glide, then remember the mouse`	61	`// Stop the trackball glide, then remember the mouse`
62	`// down point (for a future rotate, pan or zoom).`	62	`// down point (for a future rotate, pan or zoom).`
63	`void QuatTrackBall::set_position(const Vec2f& _last_pos)`	63	`void QuatTrackBall::set_position(const Vec2f& _last_pos)`
64	`{`	64	`{`
65	`stop_spin();`	65	`stop_spin();`
66	`last_pos = _last_pos;`	66	`last_pos = _last_pos;`
67	`}`	67	`}`
68		68
69	`// Rotationaly spin the trackball by the current increment.`	69	`// Rotationaly spin the trackball by the current increment.`
70	`// Use this to implement rotational glide.`	70	`// Use this to implement rotational glide.`
71	`void QuatTrackBall::do_spin()`	71	`void QuatTrackBall::do_spin()`
72	`{`	72	`{`
73	`qrot = qrot*qinc;`	73	`qrot = qrot*qinc;`
74	`}`	74	`}`
75		75
76	`// Cease any rotational glide by zeroing the increment.`	76	`// Cease any rotational glide by zeroing the increment.`
77	`void QuatTrackBall::stop_spin()`	77	`void QuatTrackBall::stop_spin()`
78	`{`	78	`{`
79	`qinc.set(0.0, 0.0, 0.0, 1.0);`	79	`qinc.set(0.0, 0.0, 0.0, 1.0);`
80	`}`	80	`}`
81		81
82	`void QuatTrackBall::rotate(const Vec2f& new_v)`	82	`void QuatTrackBall::rotate(const Vec2f& new_v)`
83	`{`	83	`{`
84	`calcRotation(new_v);`	84	`calcRotation(new_v);`
85	`do_spin();`	85	`do_spin();`
86	`}`	86	`}`
87		87
88	`void QuatTrackBall::pan(const Vec2f& new_v)`	88	`void QuatTrackBall::pan(const Vec2f& new_v)`
89	`{`	89	`{`
90	`trans += (new_v - last_pos) * Vec2f(scale[0], scale[1]);`	90	`trans += (new_v - last_pos) * Vec2f(scale[0], scale[1]);`
91	`}`	91	`}`
92		92
93	`void QuatTrackBall::zoom(const Vec2f& new_v)`	93	`void QuatTrackBall::zoom(const Vec2f& new_v)`
94	`{`	94	`{`
95	`eye_dist += (new_v[1] - last_pos[1]) * scale[2];`	95	`eye_dist += (new_v[1] - last_pos[1]) * scale[2];`
96	`eye_dist = max(eye_dist, 0.01f);`	96	`eye_dist = max(eye_dist, 0.01f);`
97	`}`	97	`}`
98		98
99	`void QuatTrackBall::calcRotation(const Vec2f& new_pos)`	99	`void QuatTrackBall::calcRotation(const Vec2f& new_pos)`
100	`{`	100	`{`
101	`// Check for zero rotation`	101	`// Check for zero rotation`
102	`if (new_pos == last_pos)`	102	`if (new_pos == last_pos)`
103	`qinc = Quaternion();`	103	`qinc = Quaternion();`
104	`else`	104	`else`
105	`{`	105	`{`
106	`// Form two vectors based on input points, find rotation axis`	106	`// Form two vectors based on input points, find rotation axis`
107	`Vec3f p1 = Vec3f(new_pos[0], new_pos[1], projectToSphere(new_pos));`	107	`Vec3f p1 = Vec3f(new_pos[0], new_pos[1], projectToSphere(new_pos));`
108	`Vec3f p2 = Vec3f(last_pos[0], last_pos[1], projectToSphere(last_pos));`	108	`Vec3f p2 = Vec3f(last_pos[0], last_pos[1], projectToSphere(last_pos));`
109		109
110	`Vec3f q = cross(p1, p2); /* axis of rotation from p1 and p2 */`	110	`Vec3f q = cross(p1, p2); /* axis of rotation from p1 and p2 */`
111	`float L = sqrt(1.0f-dot(q,q) / (dot(p1,p1) * dot(p2,p2)));`	111	`float L = sqrt(1.0f-dot(q,q) / (dot(p1,p1) * dot(p2,p2)));`
112		112
113	`q.normalize(); /* q' = axis of rotation */`	113	`q.normalize(); /* q' = axis of rotation */`
114	`q = sqrt((1 - L)/2); / q' = q' * sin(phi) */`	114	`q = sqrt((1 - L)/2); / q' = q' * sin(phi) */`
115		115
116	`qinc.set(q[0],q[1],q[2],sqrt((1 + L)/2));`	116	`qinc.set(q[0],q[1],q[2],sqrt((1 + L)/2));`
117	`}`	117	`}`
118	`}`	118	`}`
119		119
120	`// Project an x,y pair onto a sphere of radius r OR a hyperbolic sheet`	120	`// Project an x,y pair onto a sphere of radius r OR a hyperbolic sheet`
121	`// if we are away from the center of the sphere.`	121	`// if we are away from the center of the sphere.`
122	`float QuatTrackBall::projectToSphere(const Vec2f& v)`	122	`float QuatTrackBall::projectToSphere(const Vec2f& v)`
123	`{`	123	`{`
124	`float d, t, z;`	124	`float d, t, z;`
125		125
126	`d = v.length();`	126	`d = v.length();`
127		127
128	`// Inside sphere`	128	`// Inside sphere`
129	`if (d < ballsize * 0.70710678118654752440) {`	129	`if (d < ballsize * 0.70710678118654752440) {`
130	`z = sqrt(ballsizeballsize - dd);`	130	`z = sqrt(ballsizeballsize - dd);`
131	`}`	131	`}`
132	`// On hyperbola`	132	`// On hyperbola`
133	`else {`	133	`else {`
134	`t = ballsize / 1.41421356237309504880;`	134	`t = ballsize / 1.41421356237309504880;`
135	`z = t*t / d;`	135	`z = t*t / d;`
136	`}`	136	`}`
137		137
138	`return z;`	138	`return z;`
139	`}`	139	`}`
140		140
141	`// Scales integer point to the range [-1, 1]`	141	`// Scales integer point to the range [-1, 1]`
142	`Vec2f QuatTrackBall::scalePoint(const Vec2i& v) const`	142	`Vec2f QuatTrackBall::scalePoint(const Vec2i& v) const`
143	`{`	143	`{`
144	`Vec2f w(v[0],height - v[1]);`	144	`Vec2f w(v[0],height - v[1]);`
145	`w -= Vec2f(screen_centre);`	145	`w -= Vec2f(screen_centre);`
146	`w /= Vec2f(width,height);`	146	`w /= Vec2f(width,height);`
147	`w = CGLA::v_min(Vec2f(1.0f), CGLA::v_max(Vec2f(-1), 2*w));`	147	`w = CGLA::v_min(Vec2f(1.0f), CGLA::v_max(Vec2f(-1), 2*w));`
148	`return w;`	148	`return w;`
149	`}`	149	`}`
150		150
151	`void QuatTrackBall::get_view_param(Vec3f& eye, Vec3f& _centre, Vec3f& up) const`	151	`void QuatTrackBall::get_view_param(Vec3f& eye, Vec3f& _centre, Vec3f& up) const`
152	`{`	152	`{`
153	`up = qrot.apply(Vec3f(0,1,0));`	153	`up = qrot.apply(Vec3f(0,1,0));`
154	`Vec3f right = qrot.apply(Vec3f(1,0,0));`	154	`Vec3f right = qrot.apply(Vec3f(1,0,0));`
155	`_centre = centre - up * trans[1] - right * trans[0];`	155	`_centre = centre - up * trans[1] - right * trans[0];`
156	`eye = qrot.apply(Vec3f(0,0,1)*eye_dist) + _centre;`	156	`eye = qrot.apply(Vec3f(0,0,1)*eye_dist) + _centre;`
157	`}`	157	`}`
158		158
159		159
160	`// Modify the current gl matrix by the trackball rotation and translation.`	160	`// Modify the current gl matrix by the trackball rotation and translation.`
161	`void QuatTrackBall::set_gl_modelview() const`	161	`void QuatTrackBall::set_gl_modelview() const`
162	`{`	162	`{`
163	`glMatrixMode(GL_MODELVIEW);`	163	`glMatrixMode(GL_MODELVIEW);`
164	`glLoadIdentity();`	164	`glLoadIdentity();`
165	`Vec3f eye;`	165	`Vec3f eye;`
166	`Vec3f _centre;`	166	`Vec3f _centre;`
167	`Vec3f up;`	167	`Vec3f up;`
168	`get_view_param(eye, _centre, up);`	168	`get_view_param(eye, _centre, up);`
169	`gluLookAt(eye[0], eye[1], eye[2],`	169	`gluLookAt(eye[0], eye[1], eye[2],`
170	`_centre[0], _centre[1], _centre[2],`	170	`_centre[0], _centre[1], _centre[2],`
171	`up[0],up[1],up[2]);`	171	`up[0],up[1],up[2]);`
172	`}`	172	`}`
173		173
174	`bool QuatTrackBall::is_spinning() const`	174	`bool QuatTrackBall::is_spinning() const`
175	`{`	175	`{`
176	`static const Quaternion null_quat(0,0,0,1);`	176	`static const Quaternion null_quat(0,0,0,1);`
177	`if(!(qinc == null_quat))`	177	`if(!(qinc == null_quat))`
178	`return true;`	178	`return true;`
179	`return false;`	179	`return false;`
180	`}`	180	`}`
181	`}`	181	`}`
182		182

Subversion Repositories gelsvn

(root)/trunk/src/GLGraphics/QuatTrackBall.cpp – Rev 152 → 178