mototrialracer/box2dqmlplugin/box2dworld.h

/*
 * Box2D QML plugin
 * Copyright (C) 2010 Nokia Corporation
 *
 * This file is part of the Box2D QML plugin.
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at
 * your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library;  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef BOX2DWORLD_H
#define BOX2DWORLD_H

#include <QDeclarativeItem>
#include <QList>
#include <QTime>

class Box2DBody;
class Box2DJoint;
class ContactListener;

class b2World;

// TODO: Maybe turn this into a property of the world, though it can't be
// changed dynamically.
static const float scaleRatio =  113.33f; //64 pixel wheel image translated to 19 inch bike wheel

/**
 * Wrapper class around a Box2D world.
 */
class Box2DWorld : public QDeclarativeItem
{
    Q_OBJECT
    Q_PROPERTY(float timeStep READ timeStep WRITE setTimeStep)
    Q_PROPERTY(int velocityIterations READ velocityIterations WRITE setVelocityIterations)
    Q_PROPERTY(int positionIterations READ positionIterations WRITE setPositionIterations)
    Q_PROPERTY(int frameTime READ frameTime WRITE setFrameTime)
    Q_PROPERTY(QPointF gravity READ gravity WRITE setGravity NOTIFY gravityChanged)
    Q_PROPERTY(int fps READ fps NOTIFY fpsChanged)
    Q_PROPERTY(bool running READ running)
    Q_PROPERTY(bool iap_enabled READ iap_enabled NOTIFY iap_statusChanged)

public:
    explicit Box2DWorld(QDeclarativeItem *parent = 0);
    ~Box2DWorld();

    /**
     * The amount of time to step through each frame in seconds.
     * By default it is 1 / 60.
     */
    float timeStep() const { return mTimeStep; }
    void setTimeStep(float timeStep) { mTimeStep = timeStep; }

    /**
     * The number of velocity iterations used to process one step.
     * 10 by default.
     */
    int velocityIterations() const
    { return mVelocityIterations; }

    void setVelocityIterations(int iterations)
    { mVelocityIterations = iterations; }

    /**
     * The number of position iterations used to process one step.
     * 10 by default.
     */
    int positionIterations() const
    { return mPositionIterations; }

    void setPositionIterations(int iterations)
    { mPositionIterations = iterations; }

    int fps() const
    { return mFps; }

    /**
     * The amount of time each frame takes in milliseconds.
     * By default it is 1000 / 60.
     */
    int frameTime() const { return mFrameTime; }
    void setFrameTime(int frameTime) { mFrameTime = frameTime; }

    QPointF gravity() const { return mGravity; }
    void setGravity(const QPointF &gravity);

    bool running() const { return mRunning; }
    
    /**
     * this property serves as conditional in QML
     */
    bool iap_enabled() const
        {
#ifdef INAPP_BILLING
        return true;
#else
        return false;
#endif        
        }

    void componentComplete();

    void registerBody(Box2DBody *body);

    void registerJoint(Box2DJoint *joint);

    b2World *world() const { return mWorld; }

    Q_INVOKABLE void stop();
    Q_INVOKABLE void start();
    Q_INVOKABLE void resetVelocities();

private slots:
    void unregisterBody();

signals:
    void gravityChanged();
    void stepped();
    void fpsChanged();
    void iap_statusChanged();

protected:
    void timerEvent(QTimerEvent *);
    QVariant itemChange(GraphicsItemChange, const QVariant &);

private:
    b2World *mWorld;
    ContactListener *mContactListener;
    float mTimeStep;
    int mVelocityIterations;
    int mPositionIterations;
    int mFrameTime;
    QPointF mGravity;
    int mTimerId;
    QList<Box2DBody*> mBodies;
    QTime time;
    int mFps;
    float lastTime;
    bool mRunning;
};

QML_DECLARE_TYPE(Box2DWorld)

#endif // BOX2DWORLD_H