camera.cpp Example File

/****************************************************************************
**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** BSD License Usage
** Alternatively, you may use this file under the terms of the BSD license
** as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of The Qt Company Ltd nor the names of its
**     contributors may be used to endorse or promote products derived
**     from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "camera.h"
Camera::Camera(const QVector3D &pos)
    : m_forward(0.0f, 0.0f, -1.0f),
      m_right(1.0f, 0.0f, 0.0f),
      m_up(0.0f, 1.0f, 0.0f),
      m_pos(pos),
      m_yaw(0.0f),
      m_pitch(0.0f)
{
}
static inline void clamp360(float *v)
{
    if (*v > 360.0f)
        *v -= 360.0f;
    if (*v < -360.0f)
        *v += 360.0f;
}
void Camera::yaw(float degrees)
{
    m_yaw += degrees;
    clamp360(&m_yaw);
    m_yawMatrix.setToIdentity();
    m_yawMatrix.rotate(m_yaw, 0, 1, 0);
    QMatrix4x4 rotMat = m_pitchMatrix * m_yawMatrix;
    m_forward = (QVector4D(0.0f, 0.0f, -1.0f, 0.0f) * rotMat).toVector3D();
    m_right = (QVector4D(1.0f, 0.0f, 0.0f, 0.0f) * rotMat).toVector3D();
}
void Camera::pitch(float degrees)
{
    m_pitch += degrees;
    clamp360(&m_pitch);
    m_pitchMatrix.setToIdentity();
    m_pitchMatrix.rotate(m_pitch, 1, 0, 0);
    QMatrix4x4 rotMat = m_pitchMatrix * m_yawMatrix;
    m_forward = (QVector4D(0.0f, 0.0f, -1.0f, 0.0f) * rotMat).toVector3D();
    m_up = (QVector4D(0.0f, 1.0f, 0.0f, 0.0f) * rotMat).toVector3D();
}
void Camera::walk(float amount)
{
    m_pos[0] += amount * m_forward.x();
    m_pos[2] += amount * m_forward.z();
}
void Camera::strafe(float amount)
{
    m_pos[0] += amount * m_right.x();
    m_pos[2] += amount * m_right.z();
}
QMatrix4x4 Camera::viewMatrix() const
{
    QMatrix4x4 m = m_pitchMatrix * m_yawMatrix;
    m.translate(-m_pos);
    return m;
}