WebSVN – gelsvn – Diff – /branches/vc2005beta-branch/src/Graphics/QuatTrackBall.cpp


#include <iostream>
#include "CGLA/CGLA.h"
#include "QuatTrackBall.h"
 
#ifdef WIN32
#include <windows.h>
#endif
 
#include <GL/glu.h>
 
using namespace std;
using namespace CGLA;
 
namespace Graphics
{
    
    QuatTrackBall::QuatTrackBall(const Vec3f& _centre, 
			 float _eye_dist,
			 unsigned _width, 
			 unsigned _height):
	centre(_centre), eye_dist(_eye_dist), scale(0.5*_eye_dist), 
	width(_width), height(_height)
	{
	// 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 87	Rev 119
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	`#ifdef WIN32`	5	`#ifdef WIN32`
6	`#include <windows.h>`	6	`#include <windows.h>`
7	`#endif`	7	`#endif`
8		8
9	`#include <GL/glu.h>`	9	`#include <GL/glu.h>`
10		10
11	`using namespace std;`	11	`using namespace std;`
12	`using namespace CGLA;`	12	`using namespace CGLA;`
13		13
14	`namespace Graphics`	14	`namespace Graphics`
15	`{`	15	`{`
16		16
17	`QuatTrackBall::QuatTrackBall(const Vec3f& _centre,`	17	`QuatTrackBall::QuatTrackBall(const Vec3f& _centre,`
18	`float _eye_dist,`	18	`float _eye_dist,`
19	`unsigned _width,`	19	`unsigned _width,`
20	`unsigned _height):`	20	`unsigned _height):`
21	`centre(_centre), eye_dist(_eye_dist), scale(0.5*_eye_dist),`	21	`centre(_centre), eye_dist(_eye_dist), scale(0.5*_eye_dist),`
22	`width(_width), height(_height)`	22	`width(_width), height(_height)`
23	`{`	23	`{`
24	`// This size should really be based on the distance from the center of`	24	`// This size should really be based on the distance from the center of`
25	`// rotation to the point on the object underneath the mouse. That`	25	`// rotation to the point on the object underneath the mouse. That`
26	`// point would then track the mouse as closely as possible. This is a`	26	`// point would then track the mouse as closely as possible. This is a`
27	`// simple example, though, so that is left as an exercise.`	27	`// simple example, though, so that is left as an exercise.`
28	`ballsize = 2.0f;`	28	`ballsize = 2.0f;`
29	`screen_centre = Vec2i(width/2, height/2);`	29	`screen_centre = Vec2i(width/2, height/2);`
30	`qrot = Quaternion(0.0, 0.0, 0.0, 1.0);`	30	`qrot = Quaternion(0.0, 0.0, 0.0, 1.0);`
31	`qinc = Quaternion(0.0, 0.0, 0.0, 1.0);`	31	`qinc = Quaternion(0.0, 0.0, 0.0, 1.0);`
32	`trans = Vec2f(0.0, 0.0);`	32	`trans = Vec2f(0.0, 0.0);`
33	`}`	33	`}`
34		34
35	`void QuatTrackBall::grab_ball(TrackBallAction act, const Vec2i& v)`	35	`void QuatTrackBall::grab_ball(TrackBallAction act, const Vec2i& v)`
36	`{`	36	`{`
37	`set_position(scalePoint(v));`	37	`set_position(scalePoint(v));`
38	`current_action = act;`	38	`current_action = act;`
39	`}`	39	`}`
40		40
41	`void QuatTrackBall::roll_ball(const Vec2i& v)`	41	`void QuatTrackBall::roll_ball(const Vec2i& v)`
42	`{`	42	`{`
43	`Vec2f w = scalePoint(v);`	43	`Vec2f w = scalePoint(v);`
44		44
45	`switch (current_action)`	45	`switch (current_action)`
46	`{`	46	`{`
47	`case ROTATE_ACTION:`	47	`case ROTATE_ACTION:`
48	`rotate(w);`	48	`rotate(w);`
49	`break;`	49	`break;`
50		50
51	`case PAN_ACTION:`	51	`case PAN_ACTION:`
52	`pan(w);`	52	`pan(w);`
53	`break;`	53	`break;`
54		54
55	`case ZOOM_ACTION:`	55	`case ZOOM_ACTION:`
56	`zoom(w);`	56	`zoom(w);`
57	`break;`	57	`break;`
58	`}`	58	`}`
59	`last_pos = w;`	59	`last_pos = w;`
60	`}`	60	`}`
61		61
62	`// Call this when the user does a mouse down.`	62	`// Call this when the user does a mouse down.`
63	`// Stop the trackball glide, then remember the mouse`	63	`// Stop the trackball glide, then remember the mouse`
64	`// down point (for a future rotate, pan or zoom).`	64	`// down point (for a future rotate, pan or zoom).`
65	`void QuatTrackBall::set_position(const Vec2f& _last_pos)`	65	`void QuatTrackBall::set_position(const Vec2f& _last_pos)`
66	`{`	66	`{`
67	`stop_spin();`	67	`stop_spin();`
68	`last_pos = _last_pos;`	68	`last_pos = _last_pos;`
69	`}`	69	`}`
70		70
71	`// Rotationaly spin the trackball by the current increment.`	71	`// Rotationaly spin the trackball by the current increment.`
72	`// Use this to implement rotational glide.`	72	`// Use this to implement rotational glide.`
73	`void QuatTrackBall::do_spin()`	73	`void QuatTrackBall::do_spin()`
74	`{`	74	`{`
75	`qrot = qrot*qinc;`	75	`qrot = qrot*qinc;`
76	`}`	76	`}`
77		77
78	`// Cease any rotational glide by zeroing the increment.`	78	`// Cease any rotational glide by zeroing the increment.`
79	`void QuatTrackBall::stop_spin()`	79	`void QuatTrackBall::stop_spin()`
80	`{`	80	`{`
81	`qinc.set(0.0, 0.0, 0.0, 1.0);`	81	`qinc.set(0.0, 0.0, 0.0, 1.0);`
82	`}`	82	`}`
83		83
84	`void QuatTrackBall::rotate(const Vec2f& new_v)`	84	`void QuatTrackBall::rotate(const Vec2f& new_v)`
85	`{`	85	`{`
86	`calcRotation(new_v);`	86	`calcRotation(new_v);`
87	`do_spin();`	87	`do_spin();`
88	`}`	88	`}`
89		89
90	`void QuatTrackBall::pan(const Vec2f& new_v)`	90	`void QuatTrackBall::pan(const Vec2f& new_v)`
91	`{`	91	`{`
92	`trans += (new_v - last_pos) * Vec2f(scale[0], scale[1]);`	92	`trans += (new_v - last_pos) * Vec2f(scale[0], scale[1]);`
93	`}`	93	`}`
94		94
95	`void QuatTrackBall::zoom(const Vec2f& new_v)`	95	`void QuatTrackBall::zoom(const Vec2f& new_v)`
96	`{`	96	`{`
97	`eye_dist += (new_v[1] - last_pos[1]) * scale[2];`	97	`eye_dist += (new_v[1] - last_pos[1]) * scale[2];`
98	`eye_dist = max(eye_dist, 0.01f);`	98	`eye_dist = max(eye_dist, 0.01f);`
99	`}`	99	`}`
100		100
101	`void QuatTrackBall::calcRotation(const Vec2f& new_pos)`	101	`void QuatTrackBall::calcRotation(const Vec2f& new_pos)`
102	`{`	102	`{`
103	`// Check for zero rotation`	103	`// Check for zero rotation`
104	`if (new_pos == last_pos)`	104	`if (new_pos == last_pos)`
105	`qinc = Quaternion();`	105	`qinc = Quaternion();`
106	`else`	106	`else`
107	`{`	107	`{`
108	`// Form two vectors based on input points, find rotation axis`	108	`// Form two vectors based on input points, find rotation axis`
109	`Vec3f p1 = Vec3f(new_pos[0], new_pos[1], projectToSphere(new_pos));`	109	`Vec3f p1 = Vec3f(new_pos[0], new_pos[1], projectToSphere(new_pos));`
110	`Vec3f p2 = Vec3f(last_pos[0], last_pos[1], projectToSphere(last_pos));`	110	`Vec3f p2 = Vec3f(last_pos[0], last_pos[1], projectToSphere(last_pos));`
111		111
112	`Vec3f q = cross(p1, p2); /* axis of rotation from p1 and p2 */`	112	`Vec3f q = cross(p1, p2); /* axis of rotation from p1 and p2 */`
113	`float L = sqrt(1.0f-dot(q,q) / (dot(p1,p1) * dot(p2,p2)));`	113	`float L = sqrt(1.0f-dot(q,q) / (dot(p1,p1) * dot(p2,p2)));`
114		114
115	`q.normalize(); /* q' = axis of rotation */`	115	`q.normalize(); /* q' = axis of rotation */`
116	`q = sqrt((1 - L)/2); / q' = q' * sin(phi) */`	116	`q = sqrt((1 - L)/2); / q' = q' * sin(phi) */`
117		117
118	`qinc.set(q[0],q[1],q[2],sqrt((1 + L)/2));`	118	`qinc.set(q[0],q[1],q[2],sqrt((1 + L)/2));`
119	`}`	119	`}`
120	`}`	120	`}`
121		121
122	`// Project an x,y pair onto a sphere of radius r OR a hyperbolic sheet`	122	`// Project an x,y pair onto a sphere of radius r OR a hyperbolic sheet`
123	`// if we are away from the center of the sphere.`	123	`// if we are away from the center of the sphere.`
124	`float QuatTrackBall::projectToSphere(const Vec2f& v)`	124	`float QuatTrackBall::projectToSphere(const Vec2f& v)`
125	`{`	125	`{`
126	`float d, t, z;`	126	`float d, t, z;`
127		127
128	`d = v.length();`	128	`d = v.length();`
129		129
130	`// Inside sphere`	130	`// Inside sphere`
131	`if (d < ballsize * 0.70710678118654752440) {`	131	`if (d < ballsize * 0.70710678118654752440) {`
132	`z = sqrt(ballsizeballsize - dd);`	132	`z = sqrt(ballsizeballsize - dd);`
133	`}`	133	`}`
134	`// On hyperbola`	134	`// On hyperbola`
135	`else {`	135	`else {`
136	`t = ballsize / 1.41421356237309504880;`	136	`t = ballsize / 1.41421356237309504880;`
137	`z = t*t / d;`	137	`z = t*t / d;`
138	`}`	138	`}`
139		139
140	`return z;`	140	`return z;`
141	`}`	141	`}`
142		142
143	`// Scales integer point to the range [-1, 1]`	143	`// Scales integer point to the range [-1, 1]`
144	`Vec2f QuatTrackBall::scalePoint(const Vec2i& v) const`	144	`Vec2f QuatTrackBall::scalePoint(const Vec2i& v) const`
145	`{`	145	`{`
146	`Vec2f w(v[0],height - v[1]);`	146	`Vec2f w(v[0],height - v[1]);`
147	`w -= Vec2f(screen_centre);`	147	`w -= Vec2f(screen_centre);`
148	`w /= Vec2f(width,height);`	148	`w /= Vec2f(width,height);`
149	`w = CGLA::v_min(Vec2f(1.0f), CGLA::v_max(Vec2f(-1), 2*w));`	149	`w = CGLA::v_min(Vec2f(1.0f), CGLA::v_max(Vec2f(-1), 2*w));`
150	`return w;`	150	`return w;`
151	`}`	151	`}`
152		152
153	`void QuatTrackBall::get_view_param(Vec3f& eye, Vec3f& _centre, Vec3f& up) const`	153	`void QuatTrackBall::get_view_param(Vec3f& eye, Vec3f& _centre, Vec3f& up) const`
154	`{`	154	`{`
155	`up = qrot.apply(Vec3f(0,1,0));`	155	`up = qrot.apply(Vec3f(0,1,0));`
156	`Vec3f right = qrot.apply(Vec3f(1,0,0));`	156	`Vec3f right = qrot.apply(Vec3f(1,0,0));`
157	`_centre = centre - up * trans[1] - right * trans[0];`	157	`_centre = centre - up * trans[1] - right * trans[0];`
158	`eye = qrot.apply(Vec3f(0,0,1)*eye_dist) + _centre;`	158	`eye = qrot.apply(Vec3f(0,0,1)*eye_dist) + _centre;`
159	`}`	159	`}`
160		160
161		161
162	`// Modify the current gl matrix by the trackball rotation and translation.`	162	`// Modify the current gl matrix by the trackball rotation and translation.`
163	`void QuatTrackBall::set_gl_modelview() const`	163	`void QuatTrackBall::set_gl_modelview() const`
164	`{`	164	`{`
165	`glMatrixMode(GL_MODELVIEW);`	165	`glMatrixMode(GL_MODELVIEW);`
166	`glLoadIdentity();`	166	`glLoadIdentity();`
167	`Vec3f eye;`	167	`Vec3f eye;`
168	`Vec3f _centre;`	168	`Vec3f _centre;`
169	`Vec3f up;`	169	`Vec3f up;`
170	`get_view_param(eye, _centre, up);`	170	`get_view_param(eye, _centre, up);`
171	`gluLookAt(eye[0], eye[1], eye[2],`	171	`gluLookAt(eye[0], eye[1], eye[2],`
172	`_centre[0], _centre[1], _centre[2],`	172	`_centre[0], _centre[1], _centre[2],`
173	`up[0],up[1],up[2]);`	173	`up[0],up[1],up[2]);`
174	`}`	174	`}`
175		175
176	`bool QuatTrackBall::is_spinning() const`	176	`bool QuatTrackBall::is_spinning() const`
177	`{`	177	`{`
178	`static const Quaternion null_quat(0,0,0,1);`	178	`static const Quaternion null_quat(0,0,0,1);`
179	`if(!(qinc == null_quat))`	179	`if(!(qinc == null_quat))`
180	`return true;`	180	`return true;`
181	`return false;`	181	`return false;`
182	`}`	182	`}`
183	`}`	183	`}`
184		184

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(root)/branches/vc2005beta-branch/src/Graphics/QuatTrackBall.cpp – Rev 87 → 119