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LibGDX Box2D: Cannot get Fixture to render

I have been recently trying to get back into LibGDX's version of Box2D, and I looked back at a demo I created a few months back, and my code looks fine, and from my Google search results, my code is fine, but for the life of me, I cannot get the Fixture to render.
Here is my (Minimalist example) code, and for the life of me, I cannot get it to work Note: I built a wrapper around the LibGDX Game class, should be self-explanatory:
public class TestBox2D extends EGGame {
int width;
int height;
static final Vector2 ZERO_GRAVITY = new Vector2(0f, 0f);
OrthographicCamera camera;
World world;
Body body;
Box2DDebugRenderer box2dDebugRenderer;
RayHandler rayHandler;
... // Removed Constructor, nothing special here.
#Override
protected void init() {
width = Gdx.graphics.getWidth() / 2;
height = Gdx.graphics.getHeight() / 2;
camera = new OrthographicCamera(width, height);
camera.position.set(width / 2, height / 2, 0);
camera.update();
world = new World(ZERO_GRAVITY, true);
box2dDebugRenderer = new Box2DDebugRenderer();
rayHandler = new RayHandler(world);
rayHandler.setCombinedMatrix(camera.combined);
// creating Body
BodyDef bodyDef = new BodyDef();
bodyDef.type = BodyDef.BodyType.StaticBody;
bodyDef.position.set(width/2, height/2);
body = world.createBody(bodyDef);
CircleShape shape = new CircleShape();
shape.setRadius(1f);
FixtureDef fixtureDef = new FixtureDef();
fixtureDef.shape = shape;
body.createFixture(fixtureDef);
}
#Override
protected void updateGame() {
world.step(1f / 30f, 6, 2);
rayHandler.update();
}
#Override
protected void renderGame() {
box2dDebugRenderer.render(world, camera.combined);
rayHandler.render();
}
#Override
public void dispose() {
world.dispose();
}
... // Removed main method, nothing special here.
}
Note that world.getBodyCount(); and world.getFixtureCount(); both return 1.

Probable causes of problem.
Check if you have called render on fixtures in either RayHandler class or Box2DDebugRenderer class.
You have not set the position of the circle shape. It might be lying on the edge and remain out of camera bounds.
Check your units. Radius of circle might be relatively so small that it would be invisible, or it might be so large that it might be covering entire screen.
Hope this helps.

You can try the following, one of the things mention Tanmay Patil, it resizes body:
Example:
Varible Class:
long time = 0;
float testSize = 0;
Call in your render method:
time += System.nanoTime();
if (time >= 100000000){
time = 0;
testSize += (0.1f);
body.getFixtureList().first().getShape().setRadius(testSize);
}
if not notice any change, try the opposite:
time += System.nanoTime();
if (time >= 100000000){
time = 0;
testSize -= (0.1f);
body.getFixtureList().first().getShape().setRadius(testSize);
}
Edit:
On the other hand, this does not affect the question, but you can call dispose here if you want:
.////////////
CircleShape shape = new CircleShape();
shape.setRadius(1f);
FixtureDef fixtureDef = new FixtureDef();
fixtureDef.shape = shape;
body.createFixture(fixtureDef);
shape.dispose();
}

Fixed.
The issue was that I was attempting to call RayHandler#render() after Box2DDebugRenderer.render(...) while the RayHandler didn't have any Light objects (Adding a PointLight allowed it to render), but whatever the reason for it is, it's weird, but calling the RayHandler#render() first allows it to work. This might be a bug in LibGDX that I will report.

Box2d setAngularVelocity do not work for high speeds

I am using Box2d for a game, and although I use large constants to set angular velocity, the fastest speed I can get is 1 revolution at 3.86 seconds.
I had checked my source code in the following thread and everything is the same with what I have been suggested from both users in here and in tutorials:
setAngularVelocity rotates really slowly
However than I noticed the following unresolved thread:
http://www.reddit.com/r/libgdx/comments/1qr2m3/the_strangest_libgdxbox2d_behaviour/
and noticed that might actually be the problem. Here is my dispose method
public void dispose() {
//Get Rid of Everything!
Assets.Clear();
GameEngine.Clear();
BallMap.clear();
PlayerMap.clear();
shapeRenderer.dispose();
debugRenderer.dispose();
world.dispose();
batch.dispose();
font.dispose();
}
They are all reinitialized on the beginning as follows:
this.game = game;
this.cameraWidth = cameraWidth*pixelRatio;
this.cameraHeight = cameraHeight*pixelRatio;
batch = new SpriteBatch();
shapeRenderer = new ShapeRenderer();
stateTime = 0F;
Scores = new Integer[]{0, 0};
debugRenderer = new Box2DDebugRenderer();
world = new World(new Vector2(0, 0), true); //Create a world with no gravity
GameEngine.setContactListener(world);
I navigate through screens with the following code:
public void create () {
scene_menu = new MainMenuScreen(this, cameraWidth, cameraHeight);
setScreen(scene_menu);
}
public void swtogame(){
scene_menu.dispose();
scene_game = new MatchScreen(this, cameraWidth, cameraHeight);
setScreen(scene_game);
}
public void swtomenu(){
scene_game.dispose();
scene_menu = new MainMenuScreen(this, cameraWidth, cameraHeight);
setScreen(scene_menu);
}
the way i initialize objects:
public Object(World world, short category, short mask, float x, float y, float radius, Sprite image,
float maxSpeed, float frictionStrength, float linearDamping, float angularDamping, boolean movable,
float elasticity, float mass){
this.world = world;
this.category = category;
this.mask = mask;
// We set our body type
this.bodyDef = new BodyDef();
if(movable==true){bodyDef.type = BodyType.DynamicBody;}else{bodyDef.type = BodyType.StaticBody;}
// Set body's starting position in the world
bodyDef.position.set(x, y);
bodyDef.linearDamping = linearDamping;
bodyDef.angularDamping = angularDamping;
// Create our body in the world using our body definition
this.body = world.createBody(bodyDef);
// Create a circle shape and set its radius
CircleShape circle = new CircleShape();
circle.setRadius(radius);
// Create a fixture definition to apply our shape to
fixtureDef = new FixtureDef();
fixtureDef.shape = circle;
fixtureDef.density = (float) (mass/(Math.PI*radius*radius));
fixtureDef.friction = frictionStrength;
fixtureDef.restitution = elasticity;
fixtureDef.filter.categoryBits = category;
fixtureDef.filter.maskBits = mask;
// Create our fixture and attach it to the body
this.fixture = body.createFixture(fixtureDef);
// BodyDef and FixtureDef don't need disposing, but shapes do.
circle.dispose();
... unrelated functions after that
}
Am I disposing correctly? Is this a bug? Is there any way to get around it and use the setAngularVelocity properly?

Because you haven't shown much code, I can I'm not 100% sure that I'm right, but I think that you are hitting the built in maximum movement limit of 2.0 units per time step. This means that at a typical framerate of 60Hz a body covering 2 units per timestep is moving at 120 m/s or 432 km/h (270 mph). Unfortunately it seems that there is no direct way to change this limit in Java, because this limit seems to be defined in the native C++ librarys.
But I think that the real problem is that you have a wrong scale. Box2D uses MKS (meters, kilograms, and seconds). And you may have used pixels instead of meters. The FAQ of Box2D suggests to use
objects [that are] between 0.1 - 10 meters
otherwise you can get strange situations.
See http://www.iforce2d.net/b2dtut/gotchas#speedlimit
and https://code.google.com/p/box2d/wiki/FAQ

I just found the problem, and it was pretty simple. Im just going to post this here for future googlers:
Object was actually rotating properly, the problem was in my drawing method, I didn't use conversion between radians to degrees in my batch.draw, and it interpreted everything in radians. I know such an amateur mistake! Thanks a lot for your time.

How to prevent two objects in collisions from crossing both

I want to know how to prevent an object in crossing another. I have a ball and a square which I can move whith my mouse. When my ball is on my square I move it (in top for example) if I go very slowly the ball remains on the square if not it crosses it.

if both of your 2 object have a fixture defined they will not be able to crossing one another this is an exmple of how a dynamic object who will be affected by physics in the BOX2D world must be created , and also this object can't tunneling through a sensor :
public Ball (World world){
this.world = world;
BodyDef bodyDef = new BodyDef();
bodyDef.type = BodyType.DYNAMIC;
bodyDef.position.set(0.0f/RATE, 0.0f/RATE);
Ballbody = world.createBody(bodyDef);
CircleShape circle = new CircleShape();
radius = (int) (Math.random()*30+15); // you can set a non randum raduis
circle.m_radius = radius/RATE;
FixtureDef fixtureDef = new FixtureDef();
fixtureDef.shape = circle;
fixtureDef.restitution = 0.8f;
fixtureDef.density = 2.0f;
fixtureDef.friction = 0.3f;
fixtureDef.filter.groupIndex = -1;
Ballbody.createFixture(fixtureDef);
Ballbody.getFixtureList().setUserData("Ballounaton"); // optional
Vec2 ballVec = new Vec2((float) (Math.random()*8+2),0.0f);
Ballbody.setLinearVelocity(ballVec);
}
make sure to define a fixture to your box2d dynamic or static object to avoid tunneling through a sensor like in this exmple :
FixtureDef fixtureDef = new FixtureDef();
fixtureDef.shape = circle;
fixtureDef.restitution = 0.8f;
fixtureDef.density = 2.0f;
fixtureDef.friction = 0.3f;
fixtureDef.filter.groupIndex = -1;
Ballbody.createFixture(fixtureDef);
according to BOX2D official documentation :
Recall that shapes don’t know about bodies and may be used
independently of the physics simulation. Therefore Box2D provides the
b2Fixture class to attach shapes to bodies. Fixtures hold the
following:
a single shape
broad-phase proxies
density, friction, and restitution
collision filtering flags
back pointer to the parent body
user data
sensor flag

Libgdx Box2D Velocity is just not fast enough

I have a rectangle that I would like to move fast but for what ever reason the faster velocity I use still seems slow. What am I doing wrong? I have also dropped a circle from above onto a surface and even tough I play with gravity it comes down like a ballon...
Some declarations
float velocity = 10000000f;
static final float BOX_STEP=1/60f;
static final int BOX_VELOCITY_ITERATIONS=6;
static final int BOX_POSITION_ITERATIONS=2;
Gravity, tried everything and they all seem to suck
world = new World(new Vector2(0, -50), true);
The ground my object is moving onto
//ground
BodyDef groundBodyDef =new BodyDef();
groundBodyDef.position.set(new Vector2(0, camera.viewportHeight * .08f));
Body groundBody = world.createBody(groundBodyDef);
PolygonShape groundBox = new PolygonShape();
groundBox.setAsBox((camera.viewportWidth) * 2, camera.viewportHeight * .08f);
groundBody.createFixture(groundBox, 0.0f);
And then here are my objects:
//ball
bodyDef = new BodyDef();
bodyDef.type = BodyType.DynamicBody;
bodyDef.position.set(new Vector2(camera.viewportWidth * .2f, camera.viewportHeight * .75f));
body = world.createBody(bodyDef);
CircleShape dynamicCircle = new CircleShape();
dynamicCircle.setRadius(camera.viewportWidth * .035f);
FixtureDef fixtureDef = new FixtureDef();
fixtureDef.shape = dynamicCircle;
fixtureDef.density = 0.5f;
fixtureDef.friction = 0.5f;
fixtureDef.restitution = 0.8f;
body.createFixture(fixtureDef);
body.setLinearVelocity(0,-100);
//slime boy
BodyDef bodyBoxDef = new BodyDef();
bodyBoxDef.type = BodyType.DynamicBody;
bodyBoxDef.position.set(new Vector2(camera.viewportWidth * .08f,camera.viewportHeight * .191f));
bodyBox = world.createBody(bodyBoxDef);
PolygonShape slimeBox = new PolygonShape();
slimeBox.setAsBox(camera.viewportWidth * .04f, camera.viewportHeight * .03f);
FixtureDef fixtureSlimeDef = new FixtureDef();
fixtureSlimeDef.shape = slimeBox;
fixtureSlimeDef.density = 1.0f;
fixtureSlimeDef.friction = 0.0f;
fixtureSlimeDef.restitution = 0.0f;
bodyBox.createFixture(fixtureSlimeDef);
debugRenderer = new Box2DDebugRenderer();
body.applyTorque(1000000000);
bodyBox.setFixedRotation(true);
bodyBox.setBullet(true);
Any one have suggestions to speed up all movement in this?
I have been using a screen 1280 by 720 but I saw from other sources smaller is better so I scaled down to 640 by 260 but still not the preformance I want. How small should I really go?

From the Box2d Manual (Section 2.2):
Box2D is tuned for meters, kilograms, and seconds. So you can consider
the extents to be in meters. Box2D generally works best when objects
are the size of typical real world objects. For example, a barrel is
about 1 meter tall. Due to the limitations of floating point
arithmetic, using Box2D to model the movement of glaciers or dust
particles is not a good idea.
See https://stackoverflow.com/a/4556714/960524

Strange error when creating physics body in Andengine

I`m trying to create a polygonal physics body by such code:
final float halfWidth = pAreaShape.getWidthScaled() * 0.5f / PIXEL_TO_METER_RATIO_DEFAULT;
final float halfHeight = pAreaShape.getHeightScaled() * 0.5f / PIXEL_TO_METER_RATIO_DEFAULT;
final float centerX = 0;
final float left = -halfWidth;
final float right = halfWidth;
final float top = -halfHeight + 9f / PIXEL_TO_METER_RATIO_DEFAULT;
final float bottom = halfHeight;
final PolygonShape shape1 = new PolygonShape();
final Vector2[] vertices = {
new Vector2(centerX, bottom),
new Vector2(left+8f/PIXEL_TO_METER_RATIO_DEFAULT, bottom-19f/PIXEL_TO_METER_RATIO_DEFAULT),
new Vector2(left+7f/PIXEL_TO_METER_RATIO_DEFAULT, bottom-23f/PIXEL_TO_METER_RATIO_DEFAULT),
new Vector2(left+10f/PIXEL_TO_METER_RATIO_DEFAULT, top+14f/PIXEL_TO_METER_RATIO_DEFAULT),
new Vector2(left+13f/PIXEL_TO_METER_RATIO_DEFAULT, top+8f/PIXEL_TO_METER_RATIO_DEFAULT),
new Vector2(right-14f/PIXEL_TO_METER_RATIO_DEFAULT, top+8f/PIXEL_TO_METER_RATIO_DEFAULT),
new Vector2(right-11f/PIXEL_TO_METER_RATIO_DEFAULT, top+14f/PIXEL_TO_METER_RATIO_DEFAULT),
new Vector2(right-9f/PIXEL_TO_METER_RATIO_DEFAULT, bottom-23f/PIXEL_TO_METER_RATIO_DEFAULT),
new Vector2(right-10f/PIXEL_TO_METER_RATIO_DEFAULT, bottom-19f/PIXEL_TO_METER_RATIO_DEFAULT)
};
Body body = PhysicsFactory.createPolygonBody(pPhysicsWorld, pAreaShape, vertices, pBodyType, pFixtureDef);
Variable vertices contains vertices of this shape.
And it doesn`t work — applications starts(shows black screen and applications title bar), than it quits without any errors(there is no crash dialog and no errors in LogCat).
BUT when i delete one of the elements of vertices array, it works fine.
What i`m doing wrong?

Box2D has a maximum of 8 vertices in a polygon, and will fail by assertion if you specify more. I'm not sure what version of Box2D ANDEngine uses, but try making a loop or edge shape