Qt Reference Documentation

car.cpp Example File

dbus/remotecontrolledcar/car/car.cpp
 /****************************************************************************
 **
 ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
 ** Contact: Nokia Corporation (qt-info@nokia.com)
 **
 ** This file is part of the examples of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** 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 Nokia Corporation and its Subsidiary(-ies) 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 "car.h"
 #include <QtGui/QtGui>
 #include <math.h>

 static const double Pi = 3.14159265358979323846264338327950288419717;

 QRectF Car::boundingRect() const
 {
     return QRectF(-35, -81, 70, 115);
 }

 Car::Car() : color(Qt::green), wheelsAngle(0), speed(0)
 {
     startTimer(1000 / 33);
     setFlag(QGraphicsItem::ItemIsMovable, true);
     setFlag(QGraphicsItem::ItemIsFocusable, true);
 }

 void Car::accelerate()
 {
     if (speed < 10)
         ++speed;
 }

 void Car::decelerate()
 {
     if (speed > -10)
         --speed;
 }

 void Car::turnLeft()
 {
     if (wheelsAngle > -30)
         wheelsAngle -= 5;
 }

 void Car::turnRight()
 {
     if (wheelsAngle < 30)
        wheelsAngle += 5;
 }

 void Car::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
 {
     Q_UNUSED(option);
     Q_UNUSED(widget);

     painter->setBrush(Qt::gray);
     painter->drawRect(-20, -58, 40, 2); // front axel
     painter->drawRect(-20, 7, 40, 2); // rear axel

     painter->setBrush(color);
     painter->drawRect(-25, -79, 50, 10); // front wing

     painter->drawEllipse(-25, -48, 50, 20); // side pods
     painter->drawRect(-25, -38, 50, 35); // side pods
     painter->drawRect(-5, 9, 10, 10); // back pod

     painter->drawEllipse(-10, -81, 20, 100); // main body

     painter->drawRect(-17, 19, 34, 15); // rear wing

     painter->setBrush(Qt::black);
     painter->drawPie(-5, -51, 10, 15, 0, 180 * 16);
     painter->drawRect(-5, -44, 10, 10); // cocpit

     painter->save();
     painter->translate(-20, -58);
     painter->rotate(wheelsAngle);
     painter->drawRect(-10, -7, 10, 15); // front left
     painter->restore();

     painter->save();
     painter->translate(20, -58);
     painter->rotate(wheelsAngle);
     painter->drawRect(0, -7, 10, 15); // front left
     painter->restore();

     painter->drawRect(-30, 0, 12, 17); // rear left
     painter->drawRect(19, 0, 12, 17);  // rear right
 }

 void Car::timerEvent(QTimerEvent *event)
 {
     Q_UNUSED(event);

     const qreal axelDistance = 54;
     qreal wheelsAngleRads = (wheelsAngle * Pi) / 180;
     qreal turnDistance = ::cos(wheelsAngleRads) * axelDistance * 2;
     qreal turnRateRads = wheelsAngleRads / turnDistance;  // rough estimate
     qreal turnRate = (turnRateRads * 180) / Pi;
     qreal rotation = speed * turnRate;

     rotate(rotation);
     translate(0, -speed);
     update();
 }
X

Thank you for giving your feedback.

Make sure it is related to this specific page. For more general bugs and requests, please use the Qt Bug Tracker.

[0]; s.parentNode.insertBefore(ga, s); })();