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;
  }