Develop Reference

Unity - input latency is way too high but game has decent frame rate

I implemented input for my mobile game like so:
I have some buttons and I have anywhere else on the screen.
Basically when the player touches the screen and not a button ingame, the character jumps. Now, It is implemented by using OnPointerDown and OnPointerUp that sets a bool:
public class JumpInput : MonoBehaviour
{
public static bool JUMP;
public void PointerDown()
{
JUMP = true;
}
public void PointerUp()
{
JUMP = false;
}
}
If the player is jumping, it is checked by a FixedUpdate method:
if (!movementDisabled && grounded && JumpInput.JUMP)
{
//then we can jump
currentImageIndex = 0;
animState = CharAnimStates.jumpStart;
//added again from here
//zeroing out the Y axis velocity if we had one
rb2d.velocity = new Vector2(rb2d.velocity.x, 0.0f);
//until here
jump = true;
}
As I get decent frame rates even when using post-processing, I have no clue why the input is so delayed. I require assistance to verify if my solution for "anywhere on the screen input" is viable performancewise and it not, how to improve it.

How to attach a game object to the player when it collided by player?

I am making a game in which my player is a UFO, and when the player collides with other game objects, I need the game objects to be attached or floated in the air below the player (UFO), like original UFO. I tried to attach them as a child, but it didn't worked.
I made one script as below:
if (coll) {
distance = Vector2.Distance (this.transform.position, player.transform.position);
if (distance < 2) {
this.transform.parent = encaixe.transform;
this.transform.localPosition = new Vector2 (0f, 1.2f);
this.transform.localRotation = Quaternion.identity;
encaixe.rigidbody2D.gravityScale=0;
}
}
In using this script, the gameobject is attaching, but the player is not moving as like original. The game object is pulling down or up forcefully.
Please suggest to me how to do this.

I know that this Thread is rather old, but maybe someone might come across this question and is in need of an answer.
You can actively set the Object's Position and Rotation to the UFO's on Collision.
Something like the following (pseudocode):
private bool hasCollided = false;
void OnCollisionEnter()
{
hasCollided = true;
}
void LateUpdate()
{
if (hasCollided)
{
followPlayer();
}
}
void followPlayer()
{
//update position and rotation
}

Resetting game trouble in AndEngine

I'm making a brick breaking game. I coded that when I pressed back button in-game, the game turns back to the main menu. And when I touch the Start button, I want to re-create the game. But my ball isn't moving after timer_StartCompletely is passed. In other words, my timer_ball isn't working. I have this code in my onBackPressed:
#Override
public void onBackPressed()
{
if(status == INGAME) {
scene.detachChildren();
moveBall = false;
status = MENU;
ballX = (kamera.getWidth()/2)-(32/2);
ballY = (kamera.getHeight()/2)-(32/2);
ballSpeed = 3.5f;
cx = (kamera.getWidth()/2)-(cubukTex.getWidth()/2);
cy = kamera.getHeight()-25;
this.mEngine.unregisterUpdateHandler(timer_ball);
this.mEngine.unregisterUpdateHandler(timer_club);
timer_ball.reset();
musicBackground.play();
}
}
My timer declaration:
timer_StartCompletely = new TimerHandler(0.5f, new ITimerCallback() {
#Override
public void onTimePassed(final TimerHandler pTimerHandler) {
mEngine.unregisterUpdateHandler(pTimerHandler);
mEngine.registerUpdateHandler(timer_ball);
}
});
In my timer_ball, I coded movement of ball (the ball must move certainly, if timer_ball is called).
I have also a touch event that I control the touching buttons and registering timer_StartCompletely.

When instantiating your TimerHandler, you can pass a parameter called pAutoReset (You didn't pass it, so false is passed:
public TimerHandler(final float pTimerSeconds, final ITimerCallback pTimerCallback) {
this(pTimerSeconds, false /*pAutoReset*/, pTimerCallback);
}
This parameter decides whether the TimerHandler should automatically reset itself after the time has passed (Which means that if you pass true, the callbacks are repeated).
The problem here: You didn't pass true, neither called the reset method of the TimerHandler. So if we look at the relevant code in TimeHandler.java:
if(!this.mTimerCallbackTriggered) {
this.mTimerSecondsElapsed += pSecondsElapsed;
if(this.mTimerSecondsElapsed >= this.mTimerSeconds) {
this.mTimerCallbackTriggered = true;
this.mTimerCallback.onTimePassed(this);
}
}
Your callback executes once, and now mTimerCallbackTriggered is true, so it won't execute anymore.
Solution: Either call the reset method each time before registering the TimerHandler, or create it with pAutoReset = true.

Android (AndEngine): Sprite with body attached going up and down

I was trying to make the enemies in my game go up and down; since I'm using a physic body with a Sprite on it I can't use entity modifiers, so I decided give the body a little push using the .setLinearVelocity(float x, float y) method every time its sprite reach a certain point in the screen.
With just one body works great, but I need to have other enemeis (same sprite, different body) spawning every 5 seconds and doing the same thing, but I don't know how to track them... I mean, I don't know how to control if each body reaches the Y location independently from one another...
For example, right now the code is like this:
private void add_Box_Face()
{
float random_x = (float) (28 + (int)(Math.random() * ((this.CAMERA_WIDTH - 28*2) + 1)));
final Body rectangle_face_body;
final Sprite rectangle_face = new Sprite(random_x, this.y, this.mRectangleFaceTextureRegion, this.getVertexBufferObjectManager());
rectangle_face_body = PhysicsFactory.createBoxBody(this.m_PhysicsWorld, rectangle_face, BodyType.DynamicBody, this.BOX_FIXTURE_DEF);
rectangle_face_body.setUserData("target");
//I give the body a initial push
rectangle_face_body.setLinearVelocity(0, -5);
//I register an update handler to the sprite to control if it reaches a certain Y value
rectangle_face.registerUpdateHandler(new IUpdateHandler()
{
#Override
public void onUpdate(float pSecondsElapsed)
{
if (rectangle_face.getY() >= y-50)
{
//Here I just use a flag so that later on below I can do the push
MyApp.this.setLinearVelocity = true;
}
}
#Override
public void reset()
{
// TODO Auto-generated method stub
}
});
//Here I register the physic connector and if the flag permits it, I push the body up
this.m_PhysicsWorld.registerPhysicsConnector(new PhysicsConnector(rectangle_face, rectangle_face_body, true, false)
{
#Override
public void onUpdate(float pSecondsElapsed)
{
super.onUpdate(pSecondsElapsed);
if(MyApp.this.setLinearVelocity)
{
rectangle_face_body.setLinearVelocity(0, -3);
MyApp.this.setLinearVelocity = false;
}
}
});
this.mscene.attachChild(rectangle_face);
}
With the code like this the first body do what is planned, it moves up and down but as soon as another body pops up, it falls down and the other body goes up because the boolean setLinearVelocity is always set to true, so there is a costant push upwards; when a third body comes in, the second body falls down as well and this last one takes its place going up
With this code I didn't expect much else... but I don't know what else I can try... how can I control this?
Thanks in advance :)
EDIT: Added working code in an anwser below

I suggest you separate the code for the enemy from the code for the update handler. Create a class Enemy that will contain the Sprite and Body, hold your Enemies in an array and override the onUpdate method of your PhysicsWorld so that it goes through the array of Enemies and does what you want to all of them.
Here's a code snippet showing a very simple way of doing this:
mEngine.registerUpdateHandler(new IUpdateHandler() {
#Override
public void reset() {}
#Override
public void onUpdate(float pSecondsElapsed) {
for (Enemy e : enemies) {
e.checkPositionAndBounce();
}
}
});
Please note that this may not a very good idea as this code will probably run on a thread different to the one of the physics engine, which could cause all sorts of problems. A better way would be overriding the onUpdate method of PhysicsWorld:
#Override
public void onUpdate(final float pSecondsElapsed) {
super.onUpdate();
for (Enemy e : enemies) {
e.checkPositionAndBounce();
}
}
If you are unsure of what the first snippet means, look up "anonymous inner class".

Ok, here's the final working code (I didn't create a method to check the position or a class for the enemies just because right now I'm just messing around with the mechanics; I'll create a new project when I'm ready to really start):
this.m_PhysicsWorld = new PhysicsWorld(new Vector2(0, SensorManager.GRAVITY_EARTH), false)
{
#Override
public void onUpdate(float pSecondsElapsed)
{
super.onUpdate(pSecondsElapsed);
for(int i = 0; i <= MyApp.this.mSpriteCounter; i++)
{
if (rectangle_face[i].getY() >= y-50)
{
final PhysicsConnector spritePhysicsConnector = m_PhysicsWorld.getPhysicsConnectorManager().findPhysicsConnectorByShape(rectangle_face[i]);
spritePhysicsConnector.getBody().setLinearVelocity(0, -3);
}
}
};
In this code rectangle_face[] is an array of Sprites; each sprite is created like this:
private void add_Box_Face()
{
float random_x = (float) (28 + (int)(Math.random() * ((this.CAMERA_WIDTH - 28*2) + 1)));
final Body rectangle_face_body;
rectangle_face[this.mSpriteCounter] = new Sprite(random_x, y, this.mRectangleFaceTextureRegion, this.getVertexBufferObjectManager());
rectangle_face_body = PhysicsFactory.createBoxBody(this.m_PhysicsWorld, rectangle_face[this.mSpriteCounter], BodyType.DynamicBody, this.BOX_FIXTURE_DEF);
rectangle_face_body.setUserData("target");
rectangle_face_body.setLinearVelocity(0, -5);
this.m_PhysicsWorld.registerPhysicsConnector(new PhysicsConnector(rectangle_face[this.mSpriteCounter], rectangle_face_body, true, false));
this.mscene.attachChild(rectangle_face[this.mSpriteCounter]);
}
That's it, thanks again for the help :)

knowing when map has stopped scrolling (like "moveend" in javascript API)

I need to detect when a MapView has been scrolled or zoomed, like the "moveend" event in the javascript API. I'd like to wait until the view has stopped moving, so I can then detect if I need to query my server for items withing the viewing rectangle, and if so send out a request. (actually I send a request for a slightly larger area than the viewing rectangle)
Obviously, I'd rather not send out a request for data if the view is still moving. But even worse is that I don't know that I need to send another request, leaving areas of the map missing markers.
Currently I am subclassing MapView and handling the onTouchEvent as follows:
public boolean onTouchEvent(android.view.MotionEvent ev) {
super.onTouchEvent (ev);
if (ev.getAction() == MotionEvent.ACTION_UP) {
GeoPoint center = getMapCenter();
int latSpan = getLatitudeSpan(), lngSpan = getLongitudeSpan();
/* (check if it has moved enough to need a new set of data) */
}
return true;
}
Problem is, I don't know if the view has stopped, since scrolling tends to have inertia and can keep going past the "ACTION_UP" event.
Is there some event I can tap into that will alert me when a mapview is done moving (or zooming)? If not, has anyone written logic to detect this? In theory I could make a guess by looking at all the actions, and set something to come along bit later and check it...but...that seems messy and a PITA. But if someone has already written it.... :)

This is the method I am using at the moment, I have used this and tested it, works well.
Just make sure you make your draw() method efficient. (Avoid GC in it).
//In map activity
class MyMapActivity extends MapActivity {
protected void onCreate(Bundle savedState){
setContent(R.layout.activity_map);
super.onCreate(savedSate);
OnMapMoveListener mapListener = new OnMapMoveListener(){
public void mapMovingFinishedEvent(){
Log.d("MapActivity", "Hey look! I stopped scrolling!");
}
}
// Create overlay
OnMoveOverlay mOnMoveOverlay = new OnMoveOverlay(mapListener);
// Add overlay to view.
MapView mapView = (MapView)findViewById(R.id.map_view);
// Make sure you add as the last overlay so its on the top.
// Otherwise other overlays could steal the touchEvent;
mapView.getOverlays().add(mOnMoveOverlay);
}
}
This is your OnMoveOverlay class
//OnMoveOverlay
class OnMoveOverlay extends Overlay
{
private static GeoPoint lastLatLon = new GeoPoint(0, 0);
private static GeoPoint currLatLon;
// Event listener to listen for map finished moving events
private OnMapMoveListener eventListener = null;
protected boolean isMapMoving = false;
public OnMoveOverlay(OnMapMoveListener eventLis){
//Set event listener
eventListener = eventLis;
}
#Override
public boolean onTouchEvent(android.view.MotionEvent ev)
{
super.onTouchEvent(ev);
if (ev.getAction() == MotionEvent.ACTION_UP)
{
// Added to example to make more complete
isMapMoving = true;
}
//Fix: changed to false as it would handle the touch event and not pass back.
return false;
}
#Override
public void draw(Canvas canvas, MapView mapView, boolean shadow)
{
if (!shadow)
{
if (isMapMoving)
{
currLatLon = mapView.getProjection().fromPixels(0, 0);
if (currLatLon.equals(lastLatLon))
{
isMapMoving = false;
eventListener.mapMovingFinishedEvent();
}
else
{
lastLatLon = currLatLon;
}
}
}
}
public interface OnMapMoveListener{
public void mapMovingFinishedEvent();
}
}
Just implement your own listener eventListener.mapMovingFinishedEvent(); and fire the map moving bool by another method like above and your sorted.
The idea is when the map is moving the pixel projection to the coords will be changing, once they are the same, you have finished moving.
I have updated this with newer more complete code, there was an issue with it double drawing.
We don't do anything on the shadow pass as we would just double calculate per draw pass which is a waste.
Feel Free to ask any questions :)
Thanks,
Chris

I had the same problem and "solved" it in a similar way, but I think less complicated:
As overriding computeScroll() didn't work for me, I overrode onTouchEvent, too. Then I used a Handler, that invokes a method call after 50ms, if the map center changed, the same happens again, if the map center didn't change, the listener is called. The method I invoke in onTouchEvent looks like this:
private void refreshMapPosition() {
GeoPoint currentMapCenter = getMapCenter();
if (oldMapCenter==null || !oldMapCenter.equals(currentMapCenter)) {
oldMapCenter = currentMapCenter;
handler.postDelayed(new Runnable() {
#Override
public void run() {
refreshMapPosition();
}
}, 50);
}
else {
if (onScrollEndListener!=null)
onScrollEndListener.onScrollEnd(currentMapCenter);
}
}
But I'm waiting for a real solution for this, too ...

I don't really have a satisfactory solution to this problem, but I can tell what I did to partially solve it.
I subclassed MapView and overrode the computeScroll() method, which gets the current centre-point of the map and compares it with the last-known centre-point (stored as a volatile field in the subclass). If the centre-point has changed, it fires an event to the listener of the map (I defined a custom listener interface for this).
The listener is an activity that instantiates a subclass of AsyncTask and executes it. This task pauses for 100ms in its doInBackGround() method, before performing the server data fetch.
When the listener activity receives a second map-move event (which it will do because of the stepping effect of the map movement), it checks the status of the just-executed AsyncTask. If that task is still running, it will cancel() it. It then creates a new task, and executes that.
The overall effect is that when the listeners get the flurry of map-moved events a few milliseconds apart, the only one that actually triggers the task to perform the server-fetch is the last one in the sequence. The downside is that it introduces a slight delay between the map movement happening, and the server fetch occurring.
I'm not happy with it, it's ugly, but it mitigates the problem. I would love to see a better solution to this.

I solved it using a thread and it seems to work quite good. It not only detects center changes but also zoom changes. Well, the detection is done after zooming and scrolling ends. If you need to detect zooming changes when you move up the first finger then you can modify my code a bit to detect different pointers. But I didn't need it, so didn't include it and left some homework for you :D
public class CustomMapView extends MapView {
private GeoPoint pressGP;
private GeoPoint lastGP;
private int pressZoom;
private int lastZoom;
public boolean onTouchEvent( MotionEvent event ) {
switch( event.getAction() ) {
case MotionEvent.ACTION_DOWN:
pressGP = getMapCenter();
pressZoom = getZoomLevel();
break;
case MotionEvent.ACTION_UP:
lastGP = getMapCenter();
pressZoom = getZoomLevel();
if( !pressGP.equals( lastGP ) ) {
Thread thread = new Thread() {
public void run() {
while( true ) {
try {
Thread.sleep( 100 );
} catch (InterruptedException e) {}
GeoPoint gp = getMapCenter();
int zl = getZoomLevel();
if( gp.equals( lastGP ) && zl == lastZoom)
break;
lastGP = gp;
lastZoom = zl;
}
onMapStop( lastGP );
}
};
thread.start();
}
break;
}
return super.onTouchEvent( event );
}
public void onMapStop( GeoPoint point , int zoom ){
// PUT YOUR CODE HERE
}
}

With the latest version of google maps API (V2) there is a listener to do this, i.e. GoogleMap.OnCameraChangeListener.
mGoogleMap.setOnCameraChangeListener(new GoogleMap.OnCameraChangeListener()
{
#Override
public void onCameraChange(CameraPosition cameraPosition)
{
Toast.makeText(mActivity, "Longitude : "+cameraPosition.target.longitude
+", Latitude : "+cameraPosition.target.latitude, Toast.LENGTH_SHORT).show();
}
});