car.cpp 范例文件

remotecontrolledcar/car/car.cpp
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#include "car.h" #include <QtWidgets/QtWidgets> #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; setTransform(QTransform().rotate(rotation), true); setTransform(QTransform::fromTranslate(0, -speed), true); update(); }