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Diffstat (limited to 'demos/boxes/trackball.cpp')
| -rw-r--r-- | demos/boxes/trackball.cpp | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/demos/boxes/trackball.cpp b/demos/boxes/trackball.cpp new file mode 100644 index 0000000..980f6ed --- /dev/null +++ b/demos/boxes/trackball.cpp @@ -0,0 +1,158 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the demonstration applications of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "trackball.h" + +//============================================================================// +// TrackBall // +//============================================================================// + +TrackBall::TrackBall(TrackMode mode) + : m_angularVelocity(0) + , m_paused(false) + , m_pressed(false) + , m_mode(mode) +{ + m_axis = gfx::Vector3f::vector(0, 1, 0); + m_rotation = gfx::Quaternionf::quaternion(1.0f, 0.0f, 0.0f, 0.0f); + m_lastTime = QTime::currentTime(); +} + +TrackBall::TrackBall(float angularVelocity, const gfx::Vector3f& axis, TrackMode mode) + : m_axis(axis) + , m_angularVelocity(angularVelocity) + , m_paused(false) + , m_pressed(false) + , m_mode(mode) +{ + m_rotation = gfx::Quaternionf::quaternion(1.0f, 0.0f, 0.0f, 0.0f); + m_lastTime = QTime::currentTime(); +} + +void TrackBall::push(const QPointF& p, const gfx::Quaternionf &) +{ + m_rotation = rotation(); + m_pressed = true; + m_lastTime = QTime::currentTime(); + m_lastPos = p; + m_angularVelocity = 0.0f; +} + +void TrackBall::move(const QPointF& p, const gfx::Quaternionf &transformation) +{ + if (!m_pressed) + return; + + QTime currentTime = QTime::currentTime(); + int msecs = m_lastTime.msecsTo(currentTime); + if (msecs <= 20) + return; + + switch (m_mode) { + case Plane: + { + QLineF delta(m_lastPos, p); + m_angularVelocity = delta.length() / msecs; + m_axis = gfx::Vector3f::vector(delta.dy(), -delta.dx(), 0.0f).normalized(); + m_axis = transformation.transform(m_axis); + m_rotation *= gfx::Quaternionf::rotation(delta.length(), m_axis); + } + break; + case Sphere: + { + gfx::Vector3f lastPos3D = gfx::Vector3f::vector(m_lastPos.x(), m_lastPos.y(), 0); + float sqrZ = 1 - lastPos3D.sqrNorm(); + if (sqrZ > 0) + lastPos3D[2] = sqrt(sqrZ); + else + lastPos3D.normalize(); + + gfx::Vector3f currentPos3D = gfx::Vector3f::vector(p.x(), p.y(), 0); + sqrZ = 1 - currentPos3D.sqrNorm(); + if (sqrZ > 0) + currentPos3D[2] = sqrt(sqrZ); + else + currentPos3D.normalize(); + + m_axis = gfx::Vector3f::cross(currentPos3D, lastPos3D); + float angle = asin(sqrt(m_axis.sqrNorm())); + + m_angularVelocity = angle / msecs; + m_axis.normalize(); + m_axis = transformation.transform(m_axis); + m_rotation *= gfx::Quaternionf::rotation(angle, m_axis); + } + break; + } + + m_lastPos = p; + m_lastTime = currentTime; +} + +void TrackBall::release(const QPointF& p, const gfx::Quaternionf &transformation) +{ + // Calling move() caused the rotation to stop if the framerate was too low. + move(p, transformation); + m_pressed = false; +} + +void TrackBall::start() +{ + m_lastTime = QTime::currentTime(); + m_paused = false; +} + +void TrackBall::stop() +{ + m_rotation = rotation(); + m_paused = true; +} + +gfx::Quaternionf TrackBall::rotation() const +{ + if (m_paused || m_pressed) + return m_rotation; + + QTime currentTime = QTime::currentTime(); + float angle = m_angularVelocity * m_lastTime.msecsTo(currentTime); + return m_rotation * gfx::Quaternionf::rotation(angle, m_axis); +} + |