Develop Reference

How can I drag just one object, but not all the objects in Unity? [duplicate]

so as my previous threads show, I am creating a gameObject from sprites images at runtime using this code:
tex = Resources.Load<Texture2D>("pig") as Texture2D;
Sprite sprite = new Sprite();
sprite = Sprite.Create(tex, new Rect(0, 0, 250, 150), new Vector2(0.5f, 0.5f));
GameObject newSprite = new GameObject();
newSprite.AddComponent<Rigidbody2D>();
newSprite.GetComponent<Rigidbody2D>().gravityScale = 0f;
newSprite.AddComponent<ObjectMovement>();
newSprite.AddComponent<SpriteRenderer>();
SR = newSprite.GetComponent<SpriteRenderer>();
SR.sprite = sprite;
As you see I added a script "ObjectMovement", I want to check in this script if someone is dragging this particular gameObject and if so, make it follow the touch position, just to mention - this game is 2D. I never used RaysorRaycast so I am not sure where I gone wrong. Anyway here is my script code:
public SpriteRenderer selection=null;
void Update()
{
if (Input.touchCount >= 1)
{
foreach (Touch touch in Input.touches)
{
Ray ray = Camera.main.ScreenPointToRay(touch.position);
RaycastHit hit;
switch (touch.phase)
{
case TouchPhase.Began:
if (Physics.Raycast(ray, out hit, 100))
selection = hit.transform.gameObject.GetComponent<SpriteRenderer>();
break;
case TouchPhase.Moved:
selection.transform.position = new Vector2(selection.transform.position.x + touch.position.x / 10, selection.transform.position.y + touch.position.y / 10);
break;
case TouchPhase.Ended:
selection = null;
break;
}
}
}
}
So basically - when touching the screen, fire a ray and check which gameObject is in this position, when moving the finger make it follow it. Drag and drop. Thanks.
EDIT: I noticed the script is attached to every gameObject which is not effective, any ideas?

For 2D, you use RaycastHit2D and Physics2D.Raycast instead of RaycastHit and Physics.Raycast. Those are for 3D. Secondly, Make sure to attach a collider to the Sprite. Since this is a 2D game, the collider must have word "2D" in it. For example, Box Colider 2D from the Editor. You can also use Circle Collider 2D.
I noticed the script is attached to every gameObject which is not
effective, any ideas?
Just create an empty GameObject and attach that script to it. That's it.
Here is fixed version of your code:
float tempZAxis;
public SpriteRenderer selection;
void Update()
{
Touch[] touch = Input.touches;
for (int i = 0; i < touch.Length; i++)
{
Vector2 ray = Camera.main.ScreenToWorldPoint(Input.GetTouch(i).position);
RaycastHit2D hit = Physics2D.Raycast(ray, Vector2.zero);
switch (touch[i].phase)
{
case TouchPhase.Began:
if (hit)
{
selection = hit.transform.gameObject.GetComponent<SpriteRenderer>();
if (selection != null)
{
tempZAxis = selection.transform.position.z;
}
}
break;
case TouchPhase.Moved:
Vector3 tempVec = Camera.main.ScreenToWorldPoint(touch[i].position);
tempVec.z = tempZAxis; //Make sure that the z zxis never change
if (selection != null)
{
selection.transform.position = tempVec;
}
break;
case TouchPhase.Ended:
selection = null;
break;
}
}
}
That would only work on mobile but not on the Desktop Build. I suggest you implement IBeginDragHandler, IDragHandler, IEndDragHandler and override the functions that comes with them. Now, it will work with both mobile and desktop platforms.
Note: For the second solution you have to attach the script below to all Sprites you want to drag unlike the first script above.
using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using UnityEngine.EventSystems;
public class Dragger : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{
Camera mainCamera;
float zAxis = 0;
Vector3 clickOffset = Vector3.zero;
// Use this for initialization
void Start()
{
//Comment this Section if EventSystem system is already in the Scene
addEventSystem();
mainCamera = Camera.main;
mainCamera.gameObject.AddComponent<Physics2DRaycaster>();
zAxis = transform.position.z;
}
public void OnBeginDrag(PointerEventData eventData)
{
clickOffset = transform.position - mainCamera.ScreenToWorldPoint(new Vector3(eventData.position.x, eventData.position.y, zAxis));
}
public void OnDrag(PointerEventData eventData)
{
//Use Offset To Prevent Sprite from Jumping to where the finger is
Vector3 tempVec = mainCamera.ScreenToWorldPoint(eventData.position) + clickOffset;
tempVec.z = zAxis; //Make sure that the z zxis never change
transform.position = tempVec;
}
public void OnEndDrag(PointerEventData eventData)
{
}
//Add Event Syste to the Camera
void addEventSystem()
{
GameObject eventSystem = new GameObject("EventSystem");
eventSystem.AddComponent<EventSystem>();
eventSystem.AddComponent<StandaloneInputModule>();
}
}

FadeOut Action in libgdx

I'm trying to animate all the actors in a stage but FadeOut Action doesn't work
although the other actions work fine
I have the following code
getRoot().setPosition(Gdx.graphics.getWidth(), 0);
getRoot().getColor().a = 0;
SequenceAction sequenceAction = new SequenceAction();
sequenceAction.addAction(Actions.moveTo(0, 0, 3.0f));
sequenceAction.addAction(Actions.fadeOut(3.0f));
getRoot().addAction(sequenceAction);
I also tried another way to animate them by TweenEngine using class GroupAccessor implements TweenAccessor<Group> and All work fine except manipulating alpha value
public class GroupAccessor implements TweenAccessor<Group> {
public static final int ALPHA = 0;
public static final int POS_XY = 1;
#Override
public int getValues(Group target, int tweenType, float[] returnValues) {
switch (tweenType) {
case ALPHA :
returnValues[0] = target.getColor().a;
return 1;
case POS_XY :
returnValues[0] = target.getX();
returnValues[1] = target.getY();
return 2;
default:
assert false;
return -1;
}
}
#Override
public void setValues(Group target, int tweenType, float[] newValues) {
switch (tweenType) {
case ALPHA :
target.setColor(target.getColor().r, target.getColor().g, target.getColor().b,
newValues[0]);
break;
case POS_XY :
target.setPosition(newValues[0], newValues[1]);
break;
default:
assert false;
}
}
}
Animation using TweenEngine
Timeline.createSequence().
push(Tween.set(getRoot(), GroupAccessor.POS_XY).target(Gdx.graphics.getWidth(),0))
.push(Tween.to(getRoot(), GroupAccessor.POS_XY, 3.0f).target(0,0))
.push(Tween.set(getRoot(), GroupAccessor.ALPHA).target(0))
.push(Tween.to(getRoot(), GroupAccessor.ALPHA, 3.0f).target(1)).start(manager);
I have multiple actors and I made arrays of some of these actors. Here are 2 examples of draw() method of 2 actors
public void draw(Batch batch, float parentAlpha) {
batch.draw(wallSprite, 0, 0, Constants.WIDTH, Constants.HEIGHT);
}
public void draw(Batch batch, float parentAlpha) {
batch.draw(gearSprite, getX(), getY(),
gearSprite.getOriginX(), gearSprite.getOriginY(), gearSprite.getWidth(),
gearSprite.getHeight(), gearSprite.getScaleX(), gearSprite.getScaleY()
, gearSprite.getRotation());
try {
batch.draw(permittedCSprite, getX() + gearSprite.getWidth()/2
- permittedCSprite.getWidth()/2, getY() +
gearSprite.getHeight()/2 - permittedCSprite.getHeight()/2,
permittedCSprite.getWidth(), permittedCSprite.getHeight());
}
catch (NullPointerException e) {}
}

The draw method of an Actor absolutely must set a color on the Batch. This is necessary to support fading. Even if you don't care about fading or changing the color of the actor, you would still need to change the color of the Batch to WHITE to ensure what color the actor is drawn with (because there is no guarantee of what color some other actor has left the batch at.
Typically, you would have something like this at the top of your draw method:
public void draw (Batch batch, float parentAlpha) {
Color color = getColor();
batch.setColor(color.r, color.g, color.b, color.a * parentAlpha);
//...
}
However, if your Actor is drawing a Sprite instead of a TextureRegion, then you must set the color on the Sprite instead. This is because sprites have their own color which they pass on to the batch when you call sprite.draw.
If you are using a Sprite (which I don't recommend with Actors), your draw method should look something like this:
public void draw (Batch batch, float parentAlpha) {
sprite.setColor(getColor());
sprite.draw(batch, parentAlpha);
}
One "gotcha" is that Sprite is a subclass of TextureRegion. Sprite is a TextureRegion that holds information about color, size, orientation, position, etc, so it can be drawn a little bit faster (possibly) than a TextureRegion. It does this at the cost of using more memory. If you are using a Sprite, you should be calling sprite.draw not batch.draw(sprite ...), because the second option treats the sprite as a TextureRegion.
If you want to use Sprite, then you need to apply all the attributes you need to the sprite. For example:
public void draw (Batch batch, float parentAlpha) {
sprite.setColor(getColor());
sprite.setPosition(getX(), getY());
sprite.setSize(getWidth(), getHeight());
//etc. etc. etc. :(
sprite.draw(batch, parentAlpha);
}
For this reason, it really doesn't make sense to use a Sprite in an Actor at all. Way too much redundancy. Just use TextureRegions.

Making a sprite jump in AndEngine using pshysics box 2d

I have a sprite, how do I make it jump using the andEngine extension PhsycicsBox2D?
currently, I have done everything but it doesn't jump.
OnTouch to let it jump
#Override
public boolean onSceneTouchEvent(Scene pScene,
TouchEvent pSceneTouchEvent) {
// TODO Auto-generated method stub
if (pSceneTouchEvent.isActionDown())
{
b.setLinearVelocity(new Vector2(b.getLinearVelocity().x, -13.5f));
}
return false;
}
The player, physics world, body, and the connector.
player = new AnimatedSprite(playerX, playerY, this.mPlayerTextureRegion, getVertexBufferObjectManager());
physicsWorld = new PhysicsWorld(new Vector2(0, SensorManager.GRAVITY_EARTH), false);
mScene.registerUpdateHandler(physicsWorld);
final FixtureDef objectFixtureDef = PhysicsFactory.createFixtureDef(1, 0.5f, 0.5f);
b = PhysicsFactory.createBoxBody(physicsWorld, player, BodyType.StaticBody, objectFixtureDef);
physicsWorld.registerPhysicsConnector(new PhysicsConnector(player, b, true, true));
mScene.attachChild(player);

you have to update sprites position every time in your update Handler as follows: get all bodies in world Now get position of body then update sprite position
mScene.registerUpdateHandler(new Timer(1f, new ITimerCallback() {
#Override
public void onTick() {
Iterator<Body> it = bxWorld.getBodies();`
while(it.hasNext()) {
Body b = it.next();
Object userData = b.getUserData();
if (userData != null && userData instanceof Sprite) {
//Synchronize the Sprites position and rotation with the corresponding body
final Sprite sprite = (Sprite)userData;
final Vector2 pos = b.getPosition();
sprite.setPosition(pos.x * PTM_RATIO, pos.y * PTM_RATIO);
sprite.setRotation(-1.0f * ccMacros.CC_RADIANS_TO_DEGREES(b.getAngle()));
}
}
}
}));
If you want to check for bodies visibility, use debug draw class.

Try using Pathmodifire
http://code.google.com/p/andengineexamples/source/browse/src/org/anddev/andengine/examples/PathModifierExample.java?r=4f9e33fa42af65ad61057787d03f2c08fc551b62
Pathmodifire will do the trick
pass the coordinate of current position to next position (Jump position)

ParallaxBackground AndEngine

I'm new to game development andengine. I want to add ParallaxBackground but I don't know how to change background on player move. I'm using arrow for moving a player. Now my question is where I write the code parallaxBackground.setParallaxValue(5); I was written this line in onAreaTouched method of arrow but it not work. please help me. Thanks.
Code
private Camera mCamera;
private static int CAMERA_WIDTH = 800;
private static int CAMERA_HEIGHT = 480;
private BitmapTextureAtlas bgTexture;
private ITextureRegion bgTextureRegion;
#Override
protected void onCreateResources() {
BitmapTextureAtlasTextureRegionFactory.setAssetBasePath("gfx/");
bgTexture = new BitmapTextureAtlas(getTextureManager(),2160,480,TextureOptions.REPEATING_BILINEAR);
bgTextureRegion = BitmapTextureAtlasTextureRegionFactory.createFromAsset(bgTexture, this, "background.png", 0, 0);
bgTexture.load();
}
#Override
protected Scene onCreateScene() {
this.getEngine().registerUpdateHandler(new FPSLogger());
Scene scene = new Scene();
scene.setBackground(new Background(Color.BLACK));
final ParallaxBackground parallaxBackground = new ParallaxBackground(0, 0, 0);
final VertexBufferObjectManager vertexBufferObjectManager = this.getVertexBufferObjectManager();
parallaxBackground.attachParallaxEntity(new ParallaxEntity(0.0f, new Sprite(0, CAMERA_HEIGHT - this.bgTextureRegion.getHeight(), this.bgTextureRegion, vertexBufferObjectManager)));
scene.setBackground(parallaxBackground);
Robot robot = new Robot();
// add Player
final AnimatedSprite animatedRobotSprite = new AnimatedSprite(robot.centerX, robot.centerY, 122, 126, (ITiledTextureRegion) robotTextureRegion, getVertexBufferObjectManager());
scene.attachChild(animatedRobotSprite);
animatedRobotSprite.animate(new long[]{1250,50,50});
// add right arrow button
Sprite rightArrowSprite = new Sprite(0, CAMERA_HEIGHT-70, rightArrowTextureRegion, getVertexBufferObjectManager()){
#Override
public boolean onAreaTouched(TouchEvent pSceneTouchEvent,float pTouchAreaLocalX, float pTouchAreaLocalY) {
switch (pSceneTouchEvent.getAction()) {
case TouchEvent.ACTION_DOWN:
moveRight = true;
parallaxBackground.setParallaxValue(5);
break;
case TouchEvent.ACTION_MOVE:
moveRight = true;
break;
case TouchEvent.ACTION_UP:
moveRight = false;
break;
default:
break;
}
return super.onAreaTouched(pSceneTouchEvent, pTouchAreaLocalX, pTouchAreaLocalY);
}
};
scene.attachChild(rightArrowSprite);
scene.registerTouchArea(rightArrowSprite);
scene.setTouchAreaBindingOnActionDownEnabled(true);
scene.setTouchAreaBindingOnActionMoveEnabled(true);
scene.registerUpdateHandler(new IUpdateHandler() {
#Override
public void reset() {
}
#Override
public void onUpdate(float pSecondsElapsed) {
if ( moveRight ){
animatedRobotSprite.setPosition(animatedRobotSprite.getX()+speedX, animatedRobotSprite.getY());
}
}
});
return scene;
}

I see at least on possible problem: You have only one ParallaxEntity attached. The visual effect of parallax is created by multiple entities moving at different speeds.
But I think what you are seeing is that your background is not scrolling. If you do not use the AutoParallaxBackground class, you have to update the paralax amount on each update.
Inside the autoparallax class, this is what it does onUpdate():
#Override
public void onUpdate(final float pSecondsElapsed) {
super.onUpdate(pSecondsElapsed);
this.mParallaxValue += this.mParallaxChangePerSecond * pSecondsElapsed;
}
Looking at this you can see that the setParallaxValue() is an absolute number, so to make it continually scroll, you will need to feed it a new number on each update. For example, in you main game update loop, you could feed in your player.getX() into parallaxBackground.setParallaxValue() like so:
parallaxBackground.setParallaxValue(rightArrowSprite.getX());
While this may not be the exact effect you want, you should now see the background moving when your character moves.

There are different modifiers foe updating your entity(AnimatedSprite) you can use them for movement like
final Entity playerEntity = ...;//Get player entity here.
final float jumpDuration = 2;
final float x= playerEntity.getX();
final MoveXModifiermoveModifier = new MoveXModifier(jumpDuration / 2, x+ 100, y);
playerEntity.registerEntityModifier(moveModifier );

It's not necessary to have two background moving at different speeds. With one fixed background and one "moving" background you will notice the effect when the player moves. However, I've tried setting an absolute value in
parallaxBackground.setParallaxValue(10f);
And the effect was not continuous. What it worked for me was a recipe found in Android Cookbook which is based on overriding the onUpdate of the background to change only when the camera has moved.
ParallaxBackground background = new ParallaxBackground(0.3f, 0.3f,0.9f) {
/* We'll use these values to calculate the parallax value of the background*/
float cameraPreviousX = 0;
float parallaxValueOffset = 0;
/* onUpdates to the background, we need to calculate new
* parallax values in order to apply movement to the background
* objects (the hills in this case) */
#Override
public void onUpdate(float pSecondsElapsed) {
/* Obtain the camera's current center X value */
final float cameraCurrentX = mCamera.getCenterX();
/* If the camera's position has changed since last update... */
if (cameraPreviousX != cameraCurrentX) {
/* Calculate the new parallax value offset by subtracting the previous update's camera x coordinate from the current update's camera x coordinate */
parallaxValueOffset += cameraCurrentX - cameraPreviousX;
/* Apply the parallax value offset to the background, which will in-turn offset the positions of entities attached to the background */
this.setParallaxValue(parallaxValueOffset);
/* Update the previous camera X since we're finished with this update */
cameraPreviousX = cameraCurrentX;
}
super.onUpdate(pSecondsElapsed);
}
};
background.attachParallaxEntity(new ParallaxEntity(5, hillFurthest));
Note than depending on the camera configuration, the "5" value included in the "attachParallaxEntity" may need to be negative. Otherwise, the background will move in the opposite direction of the player.

How to use the mouse joint in Android?

I want to use the MouseJoint in Java for Android. I am new in box2d and cocos2d. I don't know how to use the mouse joint.

i recomend you to see this tutorial example. Copy from it (sorry i don't like broken links :) ) ...
you drag your body with the help of the MouseJoint, it will collide with the other bodys in the world and apply force to them.
Box2d - Manual - http://www.box2d.org/manual.html#_Toc258082974
8.10 Mouse Joint
The mouse joint is used in the testbed to manipulate bodies with the mouse. It attempts to drive a point on a body towards the current position of the cursor. There is no restriction on rotation.
The mouse joint definition has a target point, maximum force, frequency, and damping ratio. The target point initially coincides with the body’s anchor point. The maximum force is used to prevent violent reactions when multiple dynamic bodies interact. You can make this as large as you like. The frequency and damping ratio are used to create a spring/damper effect similar to the distance joint.
Many users have tried to adapt the mouse joint for game play. Users often want to achieve precise positioning and instantaneous response. The mouse joint doesn’t work very well in that context. You may wish to consider using kinematic bodies instead.
So let's start..
You have to create your PhysicWorld and at least one body in it. ( Checkout the PhysicExample how to.. )
- MouseJoint method
public MouseJoint createMouseJoint(AnimatedSprite box , float x, float y)
{
final Body boxBody =
this.mPhysicsWorld.getPhysicsConnectorManager().findBodyByShape(box);
Vector2 v = boxBody.getWorldPoint(
new Vector2(x/pixelToMeteRatio, y/pixelToMeteRatio)
);
MouseJointDef mjd = new MouseJointDef();
mjd.bodyA = groundBody;
mjd.bodyB = boxBody;
mjd.dampingRatio = 0.2f;
mjd.frequencyHz = 30;
mjd.maxForce = (float) (200.0f * boxBody.getMass());
mjd.collideConnected = true;
mjd.target.set(v);
return (MouseJoint) this.mPhysicsWorld.createJoint(mjd);
}
- Touching Body
we have to override our onAreaTouched method to create an MouseJoint anchor-point on the touch position.
MouseJoint mjActive = null;
private float pixelToMeteRatio = PhysicsConstants.PIXEL_TO_METER_RATIO_DEFAULT;
#Override
public boolean onAreaTouched(
final TouchEvent pSceneTouchEvent,
final ITouchArea pTouchArea ,
final float pTouchAreaLocalX,
final float pTouchAreaLocalY )
{
if(pSceneTouchEvent.getAction() == MotionEvent.ACTION_DOWN) {
this.runOnUpdateThread(new Runnable() {
#Override
public void run() {
final AnimatedSprite face = (AnimatedSprite)pTouchArea; //The touched body
//If we have a active MouseJoint, we are just moving arround don't create an 2nd one.
if( mjActive == null)
{
Vector2 vector = new Vector2(pTouchAreaLocalX/pixelToMeteRatio,pTouchAreaLocalY/pixelToMeteRatio);
//=====================================
// GROUNDBODY - Used for the MouseJoint
//=====================================
BodyDef groundBodyDef = new BodyDef();
groundBodyDef.position.set(vector);
groundBody = mPhysicsWorld.createBody(groundBodyDef);
//====================================
// CREATE THE MOUSEJOINT
//====================================
mjActive = PhysicsJumpExample.this.createMouseJoint(face, pTouchAreaLocalX, pTouchAreaLocalY);
}
}});
return true;
}
return false;
}
- Moving the body
We are moving our finger over the scene, so we have to move the MouseJoint too.
If we release the finger.. we must destroy the MouseJoint..
#Override
public boolean onSceneTouchEvent(final Scene pScene, final TouchEvent pSceneTouchEvent) {
if(this.mPhysicsWorld != null) {
if(pSceneTouchEvent.getAction() == MotionEvent.ACTION_MOVE) {
this.runOnUpdateThread(new Runnable() {
#Override
public void run() {
if( mjActive != null ){ //If the MJ is active move it ..
// =========================================
// MOVE THE MOUSEJOINT WITH THE FINGER..
// =========================================
Vecotr2 vec = new Vector2(pSceneTouchEvent.getX()/pixelToMeteRatio, pSceneTouchEvent.getY()/pixelToMeteRatio);
mjActive.setTarget(vec);
}
}});
return true;
}
//===========================================
// RELEASE THE FINGER FROM THE SCENE..
//===========================================
if( pSceneTouchEvent.getAction() == MotionEvent.ACTION_UP ||
pSceneTouchEvent.getAction() == MotionEvent.ACTION_CANCEL
) {
this.runOnUpdateThread(new Runnable() {
#Override
public void run() {
if( mjActive != null )
{
//======================================
// DESTROY OUR MOUSEJOINT
//======================================
PhysicsJumpExample.this.mPhysicsWorld.destroyJoint(mjActive);
PhysicsJumpExample.this.mPhysicsWorld.destroyBody(groundBody);
mjActive = null;
}
}});
return true;
}
return false;
}
FYI:
To fit your needs, you have to play with this settings ( in the createMouseJoint method )
mjd.dampingRatio = 0.2f;
mjd.frequencyHz = 30;
mjd.maxForce = (float) (200.0f * boxBody.getMass());