Java 类com.badlogic.gdx.physics.box2d.MassData 实例源码

public static Body createCircle() {
    if (!BodyFactory.initialized) {
        throw new IllegalStateException("You must initialize BodyFactory before using its functions");
    }
    final BodyDef testBodyDef2 = new BodyDef();
    testBodyDef2.position.set(2, 3);
    testBodyDef2.type = BodyDef.BodyType.DynamicBody;
    testBodyDef2.fixedRotation = true;
    final Body body2 = BodyFactory.world.createBody(testBodyDef2);
    final CircleShape testShape2 = new CircleShape();
    testShape2.setRadius(1f);
    final FixtureDef testFixtureDef2 = new FixtureDef();
    testFixtureDef2.shape = testShape2;
    testFixtureDef2.density = 25f;
    testFixtureDef2.friction = 1f;
    testFixtureDef2.restitution = 0;
    body2.createFixture(testFixtureDef2);
    final MassData md = body2.getMassData();
    md.mass = 80; // kg
    body2.setMassData(md);
    // System.out.println("circle - mass: " + body2.getMassData().mass + " density: " + body2.getFixtureList().get(0).getDensity());
    testShape2.dispose();
    return body2;
}

public void create () {
    cam = new OrthographicCamera(48, 32);
    cam.position.set(0, 15, 0);
    renderer = new Box2DDebugRenderer();

    world = new World(new Vector2(0, -10), true);
    Body body = world.createBody(new BodyDef());
    CircleShape shape = new CircleShape();
    shape.setRadius(1f);
    MassData mass = new MassData();
    mass.mass = 1f;
    body.setMassData(mass);
    body.setFixedRotation(true);
    body.setType(BodyType.KinematicBody);
    body.createFixture(shape, 1);
    body.setBullet(true);
    body.setTransform(new Vector2(0, 0), body.getAngle());
    body.setLinearVelocity(new Vector2(50f, 0));
}

/**
 * @param position
 * @return Body
 */
public static Body createPlayerPlatformerBody2(final Vector2 position) {
    if (!BodyFactory.initialized) {
        throw new IllegalStateException("You must initialize BodyFactory before using its functions");
    }
    final BodyDef bodyDef = new BodyDef();
    bodyDef.position.set(position.x, position.y);
    bodyDef.type = BodyDef.BodyType.DynamicBody;
    bodyDef.fixedRotation = true;
    // create body with world
    final Body b2Body = BodyFactory.world.createBody(bodyDef);

    // create shape
    final PolygonShape boxShape = new PolygonShape();
    boxShape.setAsBox(0.4f / 2f, 1.6f / 2f); // width: 50cm, heigth: 1,8meters ... div 2, because setAsBox(...) calcs in half sizes

    // create fixture to attach shape to body
    final FixtureDef fixtureDef = new FixtureDef();
    fixtureDef.shape = boxShape;
    fixtureDef.density = 20f; // BMI of human?
    fixtureDef.friction = 0.5f;
    fixtureDef.restitution = 0.1f;
    b2Body.createFixture(fixtureDef);

    final MassData md = b2Body.getMassData();
    md.mass = 60; // kg
    b2Body.setMassData(md);
    boxShape.dispose(); // clean up!!
    return b2Body;
}

/**
 * Genera un cuerpo con forma circular
 * @param world El mundo
 * @param x posici�n X
 * @param y posicion Y
 * @return El cuerpo creado
 */
public static Body createCircleBody(World world, float x, float y) {

    // Masa (en kg)
    MassData mass = new MassData();
    mass.mass = 100f;

    // Define un cuerpo f�sico din�mico con posici�n en el mundo 2D
    BodyDef bodyDef = new BodyDef();
    bodyDef.type = BodyType.DynamicBody;
    bodyDef.position.set(x, y);
    Body body = world.createBody(bodyDef);

    // Define una forma circular de 6 unidades de di�metro
    CircleShape circle = new CircleShape();
    circle.setRadius(6f);

    // Define un elemento f�sico y sus propiedades y le asigna la forma circular
    FixtureDef fixtureDef = new FixtureDef();
    // Forma del elemento f�sico
    fixtureDef.shape = circle;
    // Densidad (kg/m^2)
    fixtureDef.density = DENSITY;
    // Coeficiente de fricci�n (0 - 1)
    fixtureDef.friction = FRICTION;
    // Elasticidad (0 - 1)
    fixtureDef.restitution = RESTITUTION;
    // A�ade el elemento f�sico al cuerpo del mundo 2D
    Fixture fixture = body.createFixture(fixtureDef);

    // Definir la masa del cuerpo modifica las propiedades (FixtureDef) y viceversa (densidad)
    body.setMassData(mass);

    circle.dispose();

    return body;
}

/**
 * Genera un cuerpo con forma de caja
 * @param world El mundo
 * @param x Posici�n x
 * @param y Posici�n y
 * @return El cuerpo creado
 */
public static Body createBoxBody(World world, float x, float y) {

    // Masa (en kg)
    MassData mass = new MassData();
    mass.mass = 100f;

    // Define un cuerpo f�sico din�mico con posici�n en el mundo 2D
    BodyDef bodyDef = new BodyDef();
    bodyDef.type = BodyType.DynamicBody;
    bodyDef.position.set(x, y);
    Body body = world.createBody(bodyDef);

    // Define una forma circular de 6 unidades de di�metro
    PolygonShape box = new PolygonShape();
    box.setAsBox(10f, 10f);

    // Define un elemento f�sico y sus propiedades y le asigna la forma circular
    FixtureDef fixtureDef = new FixtureDef();
    // Forma del elemento f�sico
    fixtureDef.shape = box;
    // Densidad (kg/m^2)
    fixtureDef.density = 10f;
    // Coeficiente de fricci�n (0 - 1)
    fixtureDef.friction = 0.4f;
    // Elasticidad (0 - 1)
    fixtureDef.restitution = 0.1f;
    // A�ade el elemento f�sico al cuerpo del mundo 2D
    Fixture fixture = body.createFixture(fixtureDef);

    // Definir la masa del cuerpo modifica las propiedades (FixtureDef) y viceversa (densidad)
    body.setMassData(mass);

    box.dispose();

    return body;
}

public Player(World world, float x, float y, float width) {
    super(Assets.getTexture("cage"), new CircleShape(), world, x, y, width);
    this.body.setLinearDamping(2);
    MassData massData = body.getMassData();
    massData.mass = 1;
    this.body.setMassData(massData);
    addController();
}

private void setMass() {
    MassData masa = new MassData();
    masa.center.set(getWidth()/2, getHeight()/2);
    masa.mass = 25; // Pesa 5 kilogr�mos.

    getBody().setMassData(masa);
    getBody().resetMassData();
}

public MassData getMassData() {
    return massData;
}

public MassData getMassData() {
    return massData;
}

public void setMassData(MassData massData) {
    body.setMassData(massData);
}

public void setMassData(float mass) {
    MassData massData = new MassData();
    massData.mass = mass;
    body.setMassData(massData);
}

public MeshData(BodyDef bodyDef, MassData massData, FixtureDef[] fixtureDefs) {
    this.bodyDef = bodyDef;
    this.massData = massData;
    this.fixtureDefs = fixtureDefs;
}

@SuppressWarnings({ "rawtypes", "unchecked" })
@Override
public Body read(Json json, JsonValue jsonData, Class type) 
{
    if(world == null)
        return null;
    BodyDef defaults = RubeDefaults.Body.definition;

    int bodyType = json.readValue("type", int.class, defaults.type.getValue(), jsonData);

    if(bodyType == BodyType.DynamicBody.getValue())
        def.type = BodyType.DynamicBody;
    else if(bodyType == BodyType.KinematicBody.getValue())
        def.type = BodyType.KinematicBody;
    else
        def.type = BodyType.StaticBody;

    def.position.set(       json.readValue("position",          Vector2.class, defaults.position,       jsonData));
    def.linearVelocity.set( json.readValue("linearVelocity",    Vector2.class, defaults.linearVelocity, jsonData));

    def.angle           = json.readValue("angle",           float.class, defaults.angle,            jsonData);
    def.angularVelocity = json.readValue("angularVelocity", float.class, defaults.angularVelocity,  jsonData);
    def.linearDamping   = json.readValue("linearDamping",   float.class, defaults.linearDamping,    jsonData);
    def.angularDamping  = json.readValue("angularDamping",  float.class, defaults.angularDamping,   jsonData);
    def.gravityScale    = json.readValue("gravityScale",    float.class, defaults.gravityScale,     jsonData);

    def.allowSleep      = json.readValue("allowSleep",      boolean.class, defaults.allowSleep,     jsonData);
    def.awake           = json.readValue("awake",           boolean.class, defaults.awake,          jsonData);
    def.fixedRotation   = json.readValue("fixedRotation",   boolean.class, defaults.fixedRotation,  jsonData);
    def.bullet          = json.readValue("bullet",          boolean.class, defaults.bullet,         jsonData);
    def.active          = json.readValue("active",          boolean.class, defaults.active,         jsonData);

    Body body = world.createBody(def);

    if(def.type == BodyType.DynamicBody)
    {
        Vector2 center = json.readValue("massData-center",  Vector2.class, jsonData);
        float mass = json.readValue("massData-mass",    float.class, 0.0f,  jsonData);
        float I = json.readValue("massData-I",  float.class, 0.0f,  jsonData);

        if(center != null)
        {
            MassData massData = new MassData();

            massData.center.set(center);
            massData.mass = mass;
            massData.I = I;

            if(massData.mass != 0.0f || massData.I != 0.0f || massData.center.x != 0.0f || massData.center.y != 0.0f)
                body.setMassData(massData);
        }
    }
    scene.parseCustomProperties(json, body, jsonData);

    String name = json.readValue("name", String.class, jsonData);
    if (name != null)
    {
       scene.putNamed(name, body);
    }

    fixtureSerializer.setBody(body);

    scene.addFixtures(json.readValue("fixture", Array.class, Fixture.class, jsonData));

    return body;
}