Example usage for com.badlogic.gdx.physics.box2d World setGravity

Introduction

In this page you can find the example usage for com.badlogic.gdx.physics.box2d World setGravity.

Prototype

public void setGravity(Vector2 gravity) 

Source Link

Document

Change the global gravity vector.

Usage

From source file:com.badlogic.gdx.tests.box2d.ApplyForce.java

License:Apache License

@Override
protected void createWorld(World world) {
    world.setGravity(new Vector2(0, 0));

    float k_restitution = 0.4f;
    Body ground;/*from   www . j ava2s . c  o  m*/

    {
        BodyDef bd = new BodyDef();
        bd.position.set(0, 20);
        ground = world.createBody(bd);

        EdgeShape shape = new EdgeShape();

        FixtureDef sd = new FixtureDef();
        sd.shape = shape;
        sd.density = 0;
        sd.restitution = k_restitution;

        shape.set(new Vector2(-20, -20), new Vector2(-20, 20));
        ground.createFixture(sd);

        shape.set(new Vector2(20, -20), new Vector2(20, 20));
        ground.createFixture(sd);

        shape.set(new Vector2(-20, 20), new Vector2(20, 20));
        ground.createFixture(sd);

        shape.set(new Vector2(-20, -20), new Vector2(20, -20));
        ground.createFixture(sd);

        shape.dispose();
    }

    {
        Transform xf1 = new Transform(new Vector2(), 0.3524f * (float) Math.PI);
        xf1.setPosition(xf1.mul(new Vector2(1, 0)));

        Vector2[] vertices = new Vector2[3];
        vertices[0] = xf1.mul(new Vector2(-1, 0));
        vertices[1] = xf1.mul(new Vector2(1, 0));
        vertices[2] = xf1.mul(new Vector2(0, 0.5f));

        PolygonShape poly1 = new PolygonShape();
        poly1.set(vertices);

        FixtureDef sd1 = new FixtureDef();
        sd1.shape = poly1;
        sd1.density = 4.0f;

        Transform xf2 = new Transform(new Vector2(), -0.3524f * (float) Math.PI);
        xf2.setPosition(xf2.mul(new Vector2(-1, 0)));

        vertices[0] = xf2.mul(new Vector2(-1, 0));
        vertices[1] = xf2.mul(new Vector2(1, 0));
        vertices[2] = xf2.mul(new Vector2(0, 0.5f));

        PolygonShape poly2 = new PolygonShape();
        poly2.set(vertices);

        FixtureDef sd2 = new FixtureDef();
        sd2.shape = poly2;
        sd2.density = 2.0f;

        BodyDef bd = new BodyDef();
        bd.type = BodyType.DynamicBody;
        bd.angularDamping = 5.0f;
        bd.linearDamping = 0.1f;

        bd.position.set(0, 2);
        bd.angle = (float) Math.PI;
        bd.allowSleep = false;
        m_body = world.createBody(bd);
        m_body.createFixture(sd1);
        m_body.createFixture(sd2);
        poly1.dispose();
        poly2.dispose();
    }

    {
        PolygonShape shape = new PolygonShape();
        shape.setAsBox(0.5f, 0.5f);

        FixtureDef fd = new FixtureDef();
        fd.shape = shape;
        fd.density = 1.0f;
        fd.friction = 0.3f;

        for (int i = 0; i < 10; i++) {
            BodyDef bd = new BodyDef();
            bd.type = BodyType.DynamicBody;

            bd.position.set(0, 5 + 1.54f * i);
            Body body = world.createBody(bd);

            body.createFixture(fd);

            float gravity = 10.0f;
            float I = body.getInertia();
            float mass = body.getMass();

            float radius = (float) Math.sqrt(2 * I / mass);

            FrictionJointDef jd = new FrictionJointDef();
            jd.localAnchorA.set(0, 0);
            jd.localAnchorB.set(0, 0);
            jd.bodyA = ground;
            jd.bodyB = body;
            jd.collideConnected = true;
            jd.maxForce = mass * gravity;
            jd.maxTorque = mass * radius * gravity;

            world.createJoint(jd);
        }

        shape.dispose();
    }
}

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From source file:com.stercore.code.net.dermetfan.utils.libgdx.box2d.Box2DMapObjectParser.java

License:Apache License

/** creates the given {@link Map Map's} {@link MapObjects} in the given {@link World}
 *  @param world the {@link World} to create the {@link MapObjects} of the given {@link Map} in
 *  @param map the {@link Map} which {@link MapObjects} to create in the given {@link World}
 *  @return the given {@link World} with the parsed {@link MapObjects} of the given {@link Map} created in it */
public World load(World world, Map map) {
    MapProperties oldMapProperties = mapProperties;
    mapProperties = map.getProperties();

    world.setGravity(vec2.set(getProperty(mapProperties, aliases.gravityX, world.getGravity().x),
            getProperty(mapProperties, aliases.gravityY, world.getGravity().y)));
    world.setAutoClearForces(getProperty(mapProperties, aliases.autoClearForces, world.getAutoClearForces()));

    if (!ignoreMapUnitScale)
        unitScale = getProperty(mapProperties, aliases.unitScale, unitScale);
    tileWidth = getProperty(mapProperties, aliases.tileWidth, tileWidth);
    tileHeight = getProperty(mapProperties, aliases.tileHeight, tileHeight);

    listener.init(this);

    @SuppressWarnings("unchecked")
    Array<MapLayer> layers = Pools.obtain(Array.class);
    layers.clear();//from w w w.j  a v a  2  s.c o m
    listener.load(map, layers);

    for (MapLayer mapLayer : layers)
        load(world, mapLayer);

    layers.clear();
    Pools.free(layers);

    mapProperties = oldMapProperties;
    return world;
}

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From source file:net.dermetfan.utils.libgdx.box2d.Box2DMapObjectParser.java

License:Apache License

/** creates the given {@link Map Map's} {@link MapObjects} in the given {@link World}  
 *  @param world the {@link World} to create the {@link MapObjects} of the given {@link Map} in
 *  @param map the {@link Map} which {@link MapObjects} to create in the given {@link World}
 *  @return the given {@link World} with the parsed {@link MapObjects} of the given {@link Map} created in it */
public World load(World world, Map map) {
    MapProperties oldMapProperties = mapProperties;
    mapProperties = map.getProperties();

    world.setGravity(vec2.set(getProperty(mapProperties, aliases.gravityX, world.getGravity().x),
            getProperty(mapProperties, aliases.gravityY, world.getGravity().y)));
    world.setAutoClearForces(getProperty(mapProperties, aliases.autoClearForces, world.getAutoClearForces()));

    if (!ignoreMapUnitScale)
        unitScale = getProperty(mapProperties, aliases.unitScale, unitScale);
    tileWidth = getProperty(mapProperties, aliases.tileWidth, tileWidth);
    tileHeight = getProperty(mapProperties, aliases.tileHeight, tileHeight);

    for (MapLayer mapLayer : map.getLayers())
        load(world, mapLayer);//ww  w .j a v a  2s. co  m

    mapProperties = oldMapProperties;
    return world;
}

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From source file:zzz.box2dtest.ApplyForce.java

License:Apache License

@Override
protected void createWorld(World world) {
    world.setGravity(new Vector2(0, 0));
    Gdx.input.setInputProcessor(this);

    float k_restitution = 0.4f;
    Body ground;/*  w  w  w .  j ava2  s  .  co m*/

    {
        BodyDef bd = new BodyDef();
        bd.position.set(0, 20);
        ground = world.createBody(bd);

        EdgeShape shape = new EdgeShape();

        FixtureDef sd = new FixtureDef();
        sd.shape = shape;
        sd.density = 0;
        sd.restitution = k_restitution;

        shape.set(new Vector2(-20, -20), new Vector2(-20, 20));
        ground.createFixture(sd);

        shape.set(new Vector2(20, -20), new Vector2(20, 20));
        ground.createFixture(sd);

        shape.set(new Vector2(-20, 20), new Vector2(20, 20));
        ground.createFixture(sd);

        shape.set(new Vector2(-20, -20), new Vector2(20, -20));
        ground.createFixture(sd);

        shape.dispose();
    }

    {
        Transform xf1 = new Transform(new Vector2(), 0.3524f * (float) Math.PI);
        xf1.setPosition(xf1.mul(new Vector2(1, 0)));

        Vector2[] vertices = new Vector2[3];
        vertices[0] = xf1.mul(new Vector2(-1, 0));
        vertices[1] = xf1.mul(new Vector2(1, 0));
        vertices[2] = xf1.mul(new Vector2(0, 0.5f));

        PolygonShape poly1 = new PolygonShape();
        poly1.set(vertices);

        FixtureDef sd1 = new FixtureDef();
        sd1.shape = poly1;
        sd1.density = 4.0f;

        Transform xf2 = new Transform(new Vector2(), -0.3524f * (float) Math.PI);
        xf2.setPosition(xf2.mul(new Vector2(-1, 0)));

        vertices[0] = xf2.mul(new Vector2(-1, 0));
        vertices[1] = xf2.mul(new Vector2(1, 0));
        vertices[2] = xf2.mul(new Vector2(0, 0.5f));

        PolygonShape poly2 = new PolygonShape();
        poly2.set(vertices);

        FixtureDef sd2 = new FixtureDef();
        sd2.shape = poly2;
        sd2.density = 2.0f;

        BodyDef bd = new BodyDef();
        bd.type = BodyType.DynamicBody;
        bd.angularDamping = 5.0f;
        bd.linearDamping = 0.1f;

        bd.position.set(0, 2);
        bd.angle = (float) Math.PI;
        bd.allowSleep = false;
        m_body = world.createBody(bd);
        m_body.createFixture(sd1);
        m_body.createFixture(sd2);
        poly1.dispose();
        poly2.dispose();
    }

    {
        PolygonShape shape = new PolygonShape();
        shape.setAsBox(0.5f, 0.5f);

        FixtureDef fd = new FixtureDef();
        fd.shape = shape;
        fd.density = 1.0f;
        fd.friction = 0.3f;

        for (int i = 0; i < 10; i++) {
            BodyDef bd = new BodyDef();
            bd.type = BodyType.DynamicBody;

            bd.position.set(0, 5 + 1.54f * i);
            Body body = world.createBody(bd);

            body.createFixture(fd);

            float gravity = 10.0f;
            float I = body.getInertia();
            float mass = body.getMass();

            float radius = (float) Math.sqrt(2 * I / mass);

            FrictionJointDef jd = new FrictionJointDef();
            jd.localAnchorA.set(0, 0);
            jd.localAnchorB.set(0, 0);
            jd.bodyA = ground;
            jd.bodyB = body;
            jd.collideConnected = true;
            jd.maxForce = mass * gravity;
            jd.maxTorque = mass * radius * gravity;

            world.createJoint(jd);
        }

        shape.dispose();
    }
}

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