8095c33bcd
Especially in examples, where we should show off our convenience functions, prefer calling these functions over doing arithmetic with M_PI (or approximations thereto) and 180 (give or take simple factors). This incidentally documents what's going on, just by the name of the function used (and reveals at least one place where variables were misnamed; the return from atan is in radians, *not* degrees). Task-number: QTBUG-58083 Change-Id: I6e5d66721cafab423378f970af525400423e971e Reviewed-by: Jüri Valdmann <juri.valdmann@qt.io> Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io> Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
146 lines
4.7 KiB
C++
146 lines
4.7 KiB
C++
/****************************************************************************
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**
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** Copyright (C) 2016 The Qt Company Ltd.
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** Contact: https://www.qt.io/licensing/
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**
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** This file is part of the examples of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:BSD$
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and The Qt Company. For licensing terms
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** and conditions see https://www.qt.io/terms-conditions. For further
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** information use the contact form at https://www.qt.io/contact-us.
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**
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** BSD License Usage
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** Alternatively, you may use this file under the terms of the BSD license
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** as follows:
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**
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** "Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions are
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** met:
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** * Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** * Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in
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** the documentation and/or other materials provided with the
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** distribution.
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** * Neither the name of The Qt Company Ltd nor the names of its
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** contributors may be used to endorse or promote products derived
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** from this software without specific prior written permission.
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**
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** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#include "car.h"
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#include <QtWidgets/QtWidgets>
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#include <qmath.h>
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QRectF Car::boundingRect() const
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{
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return QRectF(-35, -81, 70, 115);
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}
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Car::Car() : color(Qt::green), wheelsAngle(0), speed(0)
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{
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startTimer(1000 / 33);
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setFlag(QGraphicsItem::ItemIsMovable, true);
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setFlag(QGraphicsItem::ItemIsFocusable, true);
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}
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void Car::accelerate()
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{
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if (speed < 10)
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++speed;
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}
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void Car::decelerate()
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{
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if (speed > -10)
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--speed;
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}
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void Car::turnLeft()
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{
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if (wheelsAngle > -30)
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wheelsAngle -= 5;
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}
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void Car::turnRight()
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{
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if (wheelsAngle < 30)
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wheelsAngle += 5;
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}
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void Car::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
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{
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Q_UNUSED(option);
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Q_UNUSED(widget);
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painter->setBrush(Qt::gray);
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painter->drawRect(-20, -58, 40, 2); // front axel
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painter->drawRect(-20, 7, 40, 2); // rear axel
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painter->setBrush(color);
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painter->drawRect(-25, -79, 50, 10); // front wing
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painter->drawEllipse(-25, -48, 50, 20); // side pods
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painter->drawRect(-25, -38, 50, 35); // side pods
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painter->drawRect(-5, 9, 10, 10); // back pod
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painter->drawEllipse(-10, -81, 20, 100); // main body
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painter->drawRect(-17, 19, 34, 15); // rear wing
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painter->setBrush(Qt::black);
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painter->drawPie(-5, -51, 10, 15, 0, 180 * 16);
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painter->drawRect(-5, -44, 10, 10); // cocpit
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painter->save();
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painter->translate(-20, -58);
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painter->rotate(wheelsAngle);
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painter->drawRect(-10, -7, 10, 15); // front left
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painter->restore();
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painter->save();
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painter->translate(20, -58);
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painter->rotate(wheelsAngle);
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painter->drawRect(0, -7, 10, 15); // front left
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painter->restore();
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painter->drawRect(-30, 0, 12, 17); // rear left
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painter->drawRect(19, 0, 12, 17); // rear right
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}
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void Car::timerEvent(QTimerEvent *event)
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{
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Q_UNUSED(event);
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const qreal axelDistance = 54;
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qreal wheelsAngleRads = qDegreesToRadians(wheelsAngle);
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qreal turnDistance = ::cos(wheelsAngleRads) * axelDistance * 2;
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qreal turnRateRads = wheelsAngleRads / turnDistance; // rough estimate
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qreal turnRate = qRadiansToDegrees(turnRateRads);
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qreal rotation = speed * turnRate;
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setTransform(QTransform().rotate(rotation), true);
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setTransform(QTransform::fromTranslate(0, -speed), true);
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update();
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}
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