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++ // Copyright (C) 2016 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
++
++ #include "mouse.h"
++
++ #include <QGraphicsScene>
++ #include <QPainter>
++ #include <QRandomGenerator>
++ #include <QStyleOption>
++ #include <QtMath>
++
++ constexpr qreal Pi = M_PI;
++ constexpr qreal TwoPi = 2 * M_PI;
++
++ static qreal normalizeAngle(qreal angle)
++ {
++ while (angle < 0)
++ angle += TwoPi;
++ while (angle > TwoPi)
++ angle -= TwoPi;
++ return angle;
++ }
++
++ //! [0]
++ Mouse::Mouse() : color(QRandomGenerator::global()->bounded(256),
++ QRandomGenerator::global()->bounded(256),
++ QRandomGenerator::global()->bounded(256))
++ {
++ setRotation(QRandomGenerator::global()->bounded(360 * 16));
++ }
++ //! [0]
++
++ //! [1]
++ QRectF Mouse::boundingRect() const
++ {
++ qreal adjust = 0.5;
++ return QRectF(-18 - adjust, -22 - adjust,
++ 36 + adjust, 60 + adjust);
++ }
++ //! [1]
++
++ //! [2]
++ QPainterPath Mouse::shape() const
++ {
++ QPainterPath path;
++ path.addRect(-10, -20, 20, 40);
++ return path;
++ }
++ //! [2]
++
++ //! [3]
++ void Mouse::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
++ {
++ // Body
++ painter->setBrush(color);
++ painter->drawEllipse(-10, -20, 20, 40);
++
++ // Eyes
++ painter->setBrush(Qt::white);
++ painter->drawEllipse(-10, -17, 8, 8);
++ painter->drawEllipse(2, -17, 8, 8);
++
++ // Nose
++ painter->setBrush(Qt::black);
++ painter->drawEllipse(QRectF(-2, -22, 4, 4));
++
++ // Pupils
++ painter->drawEllipse(QRectF(-8.0 + mouseEyeDirection, -17, 4, 4));
++ painter->drawEllipse(QRectF(4.0 + mouseEyeDirection, -17, 4, 4));
++
++ // Ears
++ painter->setBrush(scene()->collidingItems(this).isEmpty() ? Qt::darkYellow : Qt::red);
++ painter->drawEllipse(-17, -12, 16, 16);
++ painter->drawEllipse(1, -12, 16, 16);
++
++ // Tail
++ QPainterPath path(QPointF(0, 20));
++ path.cubicTo(-5, 22, -5, 22, 0, 25);
++ path.cubicTo(5, 27, 5, 32, 0, 30);
++ path.cubicTo(-5, 32, -5, 42, 0, 35);
++ painter->setBrush(Qt::NoBrush);
++ painter->drawPath(path);
++ }
++ //! [3]
++
++ //! [4]
++ void Mouse::advance(int step)
++ {
++ if (!step)
++ return;
++ //! [4]
++ // Don't move too far away
++ //! [5]
++ QLineF lineToCenter(QPointF(0, 0), mapFromScene(0, 0));
++ if (lineToCenter.length() > 150) {
++ qreal angleToCenter = std::atan2(lineToCenter.dy(), lineToCenter.dx());
++ angleToCenter = normalizeAngle((Pi - angleToCenter) + Pi / 2);
++
++ if (angleToCenter < Pi && angleToCenter > Pi / 4) {
++ // Rotate left
++ angle += (angle < -Pi / 2) ? 0.25 : -0.25;
++ } else if (angleToCenter >= Pi && angleToCenter < (Pi + Pi / 2 + Pi / 4)) {
++ // Rotate right
++ angle += (angle < Pi / 2) ? 0.25 : -0.25;
++ }
++ } else if (::sin(angle) < 0) {
++ angle += 0.25;
++ } else if (::sin(angle) > 0) {
++ angle -= 0.25;
++ //! [5] //! [6]
++ }
++ //! [6]
++
++ // Try not to crash with any other mice
++ //! [7]
++ const QList<QGraphicsItem *> dangerMice = scene()->items(QPolygonF()
++ << mapToScene(0, 0)
++ << mapToScene(-30, -50)
++ << mapToScene(30, -50));
++
++ for (const QGraphicsItem *item : dangerMice) {
++ if (item == this)
++ continue;
++
++ QLineF lineToMouse(QPointF(0, 0), mapFromItem(item, 0, 0));
++ qreal angleToMouse = std::atan2(lineToMouse.dy(), lineToMouse.dx());
++ angleToMouse = normalizeAngle((Pi - angleToMouse) + Pi / 2);
++
++ if (angleToMouse >= 0 && angleToMouse < Pi / 2) {
++ // Rotate right
++ angle += 0.5;
++ } else if (angleToMouse <= TwoPi && angleToMouse > (TwoPi - Pi / 2)) {
++ // Rotate left
++ angle -= 0.5;
++ //! [7] //! [8]
++ }
++ //! [8] //! [9]
++ }
++ //! [9]
++
++ // Add some random movement
++ //! [10]
++ if (dangerMice.size() > 1 && QRandomGenerator::global()->bounded(10) == 0) {
++ if (QRandomGenerator::global()->bounded(1))
++ angle += QRandomGenerator::global()->bounded(1 / 500.0);
++ else
++ angle -= QRandomGenerator::global()->bounded(1 / 500.0);
++ }
++ //! [10]
++
++ //! [11]
++ speed += (-50 + QRandomGenerator::global()->bounded(100)) / 100.0;
++
++ qreal dx = ::sin(angle) * 10;
++ mouseEyeDirection = (qAbs(dx / 5) < 1) ? 0 : dx / 5;
++
++ setRotation(rotation() + dx);
++ setPos(mapToParent(0, -(3 + sin(speed) * 3)));
++ }
++ //! [11]