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41
42 #include "trackball.h"
43 #include "scene.h"
44
45 //============================================================================//
46 // TrackBall //
47 //============================================================================//
48
TrackBall(TrackMode mode)49 TrackBall::TrackBall(TrackMode mode)
50 : m_angularVelocity(0)
51 , m_paused(false)
52 , m_pressed(false)
53 , m_mode(mode)
54 {
55 m_axis = QVector3D(0, 1, 0);
56 m_rotation = QQuaternion();
57 m_lastTime = QTime::currentTime();
58 }
59
TrackBall(float angularVelocity,const QVector3D & axis,TrackMode mode)60 TrackBall::TrackBall(float angularVelocity, const QVector3D& axis, TrackMode mode)
61 : m_axis(axis)
62 , m_angularVelocity(angularVelocity)
63 , m_paused(false)
64 , m_pressed(false)
65 , m_mode(mode)
66 {
67 m_rotation = QQuaternion();
68 m_lastTime = QTime::currentTime();
69 }
70
push(const QPointF & p,const QQuaternion &)71 void TrackBall::push(const QPointF& p, const QQuaternion &)
72 {
73 m_rotation = rotation();
74 m_pressed = true;
75 m_lastTime = QTime::currentTime();
76 m_lastPos = p;
77 m_angularVelocity = 0.0f;
78 }
79
move(const QPointF & p,const QQuaternion & transformation)80 void TrackBall::move(const QPointF& p, const QQuaternion &transformation)
81 {
82 if (!m_pressed)
83 return;
84
85 QTime currentTime = QTime::currentTime();
86 int msecs = m_lastTime.msecsTo(currentTime);
87 if (msecs <= 20)
88 return;
89
90 switch (m_mode) {
91 case Plane:
92 {
93 QLineF delta(m_lastPos, p);
94 m_angularVelocity = 180*delta.length() / (PI*msecs);
95 m_axis = QVector3D(-delta.dy(), delta.dx(), 0.0f).normalized();
96 m_axis = transformation.rotatedVector(m_axis);
97 m_rotation = QQuaternion::fromAxisAndAngle(m_axis, 180 / PI * delta.length()) * m_rotation;
98 }
99 break;
100 case Sphere:
101 {
102 QVector3D lastPos3D = QVector3D(m_lastPos.x(), m_lastPos.y(), 0.0f);
103 float sqrZ = 1 - QVector3D::dotProduct(lastPos3D, lastPos3D);
104 if (sqrZ > 0)
105 lastPos3D.setZ(sqrt(sqrZ));
106 else
107 lastPos3D.normalize();
108
109 QVector3D currentPos3D = QVector3D(p.x(), p.y(), 0.0f);
110 sqrZ = 1 - QVector3D::dotProduct(currentPos3D, currentPos3D);
111 if (sqrZ > 0)
112 currentPos3D.setZ(sqrt(sqrZ));
113 else
114 currentPos3D.normalize();
115
116 m_axis = QVector3D::crossProduct(lastPos3D, currentPos3D);
117 float angle = 180 / PI * asin(sqrt(QVector3D::dotProduct(m_axis, m_axis)));
118
119 m_angularVelocity = angle / msecs;
120 m_axis.normalize();
121 m_axis = transformation.rotatedVector(m_axis);
122 m_rotation = QQuaternion::fromAxisAndAngle(m_axis, angle) * m_rotation;
123 }
124 break;
125 }
126
127
128 m_lastPos = p;
129 m_lastTime = currentTime;
130 }
131
release(const QPointF & p,const QQuaternion & transformation)132 void TrackBall::release(const QPointF& p, const QQuaternion &transformation)
133 {
134 // Calling move() caused the rotation to stop if the framerate was too low.
135 move(p, transformation);
136 m_pressed = false;
137 }
138
start()139 void TrackBall::start()
140 {
141 m_lastTime = QTime::currentTime();
142 m_paused = false;
143 }
144
stop()145 void TrackBall::stop()
146 {
147 m_rotation = rotation();
148 m_paused = true;
149 }
150
rotation() const151 QQuaternion TrackBall::rotation() const
152 {
153 if (m_paused || m_pressed)
154 return m_rotation;
155
156 QTime currentTime = QTime::currentTime();
157 float angle = m_angularVelocity * m_lastTime.msecsTo(currentTime);
158 return QQuaternion::fromAxisAndAngle(m_axis, angle) * m_rotation;
159 }
160
161