Develop Reference

How to drag an indivudual texture in libgdx android

I have two textures drawn in my 2d scene. And I want to drag them each separately. When they are touched and dragged I want both textures to be dragged to each points. How it drag them individually, or is there any other method to implement. as I am a beginner to libgdx.
My code:
public class MyGdxGame implements ApplicationListener{
OrthographicCamera camera;
ShapeRenderer shapeRenderer;
float screenOffset=10,circleRadius=30;
Texture firstTexture;
Texture secondTexture;
float firstTextureX;
float firstTextureY;
float secondTextureX;
float secondTextureY;
float touchX;
float touchY;
SpriteBatch batch;
#Override
public void create()
{
firstTexture= new Texture("b1.jpg");
firstTextureX = 50;
firstTextureY = 50;
secondTexture = new Texture("b2.jpg");
secondTextureX = 250;
secondTextureY = 250;
batch = new SpriteBatch();
camera=new OrthographicCamera();
shapeRenderer=new ShapeRenderer();
shapeRenderer.setAutoShapeType(true);
}
#Override
public void render()
{
Gdx.gl.glClearColor(1,1,1,1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
shapeRenderer.setProjectionMatrix(camera.combined);
shapeRenderer.begin();
shapeRenderer.setColor(Color.RED);
shapeRenderer.circle(camera.viewportWidth/2,camera.viewportHeight/2,circleRadius);
shapeRenderer.rect(screenOffset,screenOffset,camera.viewportWidth-2*screenOffset,camera.viewportHeight-2*screenOffset);
shapeRenderer.line(screenOffset,screenOffset,camera.viewportWidth-screenOffset,camera.viewportHeight-screenOffset);
shapeRenderer.line(screenOffset,camera.viewportHeight-screenOffset,camera.viewportWidth-screenOffset,screenOffset);
shapeRenderer.line(screenOffset,camera.viewportHeight/2,camera.viewportWidth-screenOffset,camera.viewportHeight/2);
shapeRenderer.line(camera.viewportWidth/2,screenOffset,camera.viewportWidth/2,camera.viewportHeight-screenOffset);
shapeRenderer.end();
batch.begin();
batch.draw(firstTexture, firstTextureX, firstTextureY);
batch.draw(secondTexture, secondTextureX, secondTextureY);
batch.end();
}

Well, you should save the current position of the texture, and on the update, move the texture checking the movement of the mouse if the mouse right click is active. This is the general idea, valid for any framework or code.
I recommend you to move the texture to their own class, with a getter and a setter of the position and the texture, so it's easy to manage.
Using libdgx you can check if the mouse is clicked at any time with
Gdx.input.justTouched();
On every update you can check what was the last position of the mouse and calculate the difference with the new position on every update using
Gdx.input.getX()
Gdx.input.getY()
To syncronize the position inside your screen with the position on your camera you should use unproject on your camera, for example:
Vector3 mousePos = new Vector3();
mousePos.x = Gdx.input.getX();
mousePos.y = Gdx.input.getY();
mousePos.z = 0;
camera.unproject(mousePos); //this will convert the screen position to your camera position
TL;DR you need to check what was the last position of the mouse when it was clicked, and on the next update calculate the difference, and then you update the position of the texture.
BTW, although this is for when you get more experience, you can create a class that implements InputProcessor, alow the class to be processed by libgdx with, for example:
public class CameraControllerDesktop implements InputProcessor, ControllerListener {
public CameraControllerDesktop() {
Gdx.input.setInputProcessor(this);
}
and the you could use the function
#Override
public boolean touchDragged(int screenX, int screenY, int pointer) {
return false;
}
to let libgx calculate the position of what you are dragging.
Sorry about not writing the entire solution, but if whit this info you can solve your problem, I'm pretty sure that you sooner or later will be able to make the game you want.

LibGDX Rotate 2D image with touchDragged() event

Objective: to rotate an image in the center of the screen with movement equal to left or right touchDragged event.
Right now I have a basic Stage that is created and adds an actor (centerMass.png) to the stage. it is created and rendered like this:
public class Application extends ApplicationAdapter {
Stage stageGamePlay;
#Override
public void create () {
//setup game stage variables
stageGamePlay = new Stage(new ScreenViewport());
stageGamePlay.addActor(new CenterMass(new Texture(Gdx.files.internal("centerMass.png"))));
Gdx.input.setInputProcessor(stageGamePlay);
}
#Override
public void render () {
Gdx.gl.glClearColor(255f/255, 249f/255, 236f/255, 1f);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
//before drawing, updating actions that have changed
stageGamePlay.act(Gdx.graphics.getDeltaTime());
stageGamePlay.draw();
}
}
I then have a separate class file that contains the CenterMass class, extending Image. I am familiar enough to know I could extend Actor, but I am not sure the benefit I would gain using Actor vs Image.
In the CenterMass class I create the texture, set bounds, set touchable and center it on the screen.
Inside CenterMass class I also have an InputListener listening for events. I have an override set for touchDragged where I am trying to get the X and Y of the drag, and use that to set the rotate actions accordingly. That class looks like this:
//extend Image vs Actor classes
public class CenterMass extends Image {
public CenterMass(Texture centerMassSprite) {
//let parent be aware
super(centerMassSprite);
setBounds(getX(), getY(), getWidth(), getHeight());
setTouchable(Touchable.enabled);
setPosition(Gdx.graphics.getWidth()/2, Gdx.graphics.getHeight()/2);
setRotation(90f);
addListener(new InputListener(){
private int dragX, dragY;
private float duration;
private float rotateBy = 30f;
#Override
public void touchDragged(InputEvent event, float x, float y, int pointer) {
//get
float dX = (float)(x-dragX)/(float)Gdx.graphics.getWidth();
float dY = (float)(dragY-y)/(float)Gdx.graphics.getHeight();
duration = 1.0f; // 1 second
Actions.sequence(
Actions.parallel(
Actions.rotateBy(rotateBy, duration),
Actions.moveBy( dX, dY, duration)
)
);
}
});
}
#Override
protected void positionChanged() {
//super.positionChanged();
}
#Override
public void draw(Batch batch, float parentAlpha) {
//draw needs to be available for changing color and rotation, I think
batch.setColor(this.getColor());
//cast back to texture because we use Image vs Actor and want to rotate and change color safely
((TextureRegionDrawable)getDrawable()).draw(batch, getX(), getY(),
getOriginX(), getOriginY(),
getWidth(), getHeight(),
getScaleX(), getScaleY(),
getRotation());
}
#Override
public void act(float delta) {
super.act(delta);
}
}
The Problem:
I have not been able to get it to rotate the way I would like. I have been able to get it to shift around in unpredictable ways. Any guidance would be much appreciated.

As from you code it seems everything is good. except you don't set any origin of the image. without setting the origin it is by default set to 0,0.(bottom left of your image)
So if yow want to rotate the image with origin to centre you have to set the origin to imageWidth/2. imageHeight/2.
setOrigin(imageWidth/2,imageHeight/2)// something like this

3D rotation - perspective

public class MainActivity extends Activity {
LinearLayout rotator;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
rotator = (LinearLayout) findViewById(R.id.rotator);
ObjectAnimator rotation = ObjectAnimator.ofFloat(rotator, "rotationY", 0, 360);
rotation.setDuration(3000);
rotation.start();
}
}
I've got above code, which is rotating View around Y axis. Problem is, that the perspective seems to be too "strong" - the edge of view that is in foreground becomes too big and the edge in background becomes too small. Is there any possibility to "lower down" the perspecitve factor?

int distance = 1900;
float scale = getResources().getDisplayMetrics().density;
rotator.setCameraDistance(distance * scale);
So this is the solution for all screen densities.

How to tilt a child layout at some angle

I've tried the custom view and tilt the image to 45 degree successfully but I want to tilt the whole child layoout at some angle so that whatever I'll add in that child layout will automactically tiled .. For reference please take a look at the attached picture
even I have tried this code but it wont help
public class CustomLinear extends LinearLayout{
private Matrix mForward = new Matrix();
private Matrix mReverse = new Matrix();
private float[] mTemp = new float[2];
public CustomLinear(Context context) {
super(context);
}
public CustomLinear(Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
protected void dispatchDraw(Canvas canvas) {
canvas.rotate(75, getWidth() / 2, getHeight() / 2);
mForward = canvas.getMatrix();
mForward.invert(mReverse);
canvas.save();
canvas.setMatrix(mForward); // This is the matrix we need to use for
// proper positioning of touch events
super.dispatchDraw(canvas);
canvas.restore();
invalidate();
}
#Override
public boolean dispatchTouchEvent(MotionEvent event) {
event.setLocation(getWidth() - event.getX(), getHeight() - event.getY());
return super.dispatchTouchEvent(event);
}
}

I thing it is possible using rotate animation. you can apply animation on the whole child layout with 0 duration in On_create.
Here is the animation code
<?xml version="1.0" encoding="utf-8"?>
<rotate
xmlns:android="http://schemas.android.com/apk/res/android"
android:fromDegrees="0"
android:toDegrees="-90"
android:pivotX="50%"
android:pivotY="50%"
android:duration="0"
android:fillAfter="true">
</rotate>
You can set the rotation angle as per your need.
Then use given code in your Activity's onCreate,
#Override
public void onCreate(Bundle b) {
super.onCreate(b);
setContentView(R.layout.myscreen);
Animation rotate_anim = AnimationUtils.loadAnimation(this, R.anim.rotation);
LayoutAnimationController anim_controller = new LayoutAnimationController(rotate_anim, 0);
FrameLayout layout = (FrameLayout)findViewById(R.id.MyScreen_ContentLayout);
layout.setLayoutAnimation(anim_controller);
}

Make custom (tilted/rotated) xml views and call it all in the main view.
Also, take a look at the following link this may help you.
http://mindfreakconcepts.blogspot.com/2013/03/how-to-rotate-listview-items-in-android.html

I could be wrong but from my understanding you have to use animation to get the effect that you want instead of draw. There is a similar thread, here that might be worth checking out.

Creating a 3D flip animation in Android using XML

I have created a 3D flip of a view using this android tutorial
However, I have done it programmatically and I would like to do it all in xml, if possible. I am not talking about simply shrinking a view to the middle and then back out, but an actual 3D flip.
Is this possible via xml?

Here is the answer, though it only works with 3.0 and above.
1) Create a new resources folder called "animator".
2) Create a new .xml file which I will call "flipping". Use the following xml code:
<?xml version="1.0" encoding="utf-8"?>
<objectAnimator xmlns:android="http://schemas.android.com/apk/res/android"
android:valueFrom="0" android:valueTo="360" android:propertyName="rotationY" >
</objectAnimator>
No, the objectAnimator tags do not start with an uppercase "O".
3) Start the animation with the following code:
ObjectAnimator anim = (ObjectAnimator) AnimatorInflater.loadAnimator(mContext, R.animator.flipping);
anim.setTarget(A View Object reference goes here i.e. ImageView);
anim.setDuration(3000);
anim.start();
I got all this from here.

Since the answers to this question are fairly dated, here is a more modern solution relying on ValueAnimators.
This solution implements a true, visually appealing 3D-flip, because it not just flips the view, but also scales it while it is flipping (this is how Apple does it).
First we set up the ValueAnimator:
mFlipAnimator = ValueAnimator.ofFloat(0f, 1f);
mFlipAnimator.addUpdateListener(new FlipListener(frontView, backView));
And the corresponding update listener:
public class FlipListener implements ValueAnimator.AnimatorUpdateListener {
private final View mFrontView;
private final View mBackView;
private boolean mFlipped;
public FlipListener(final View front, final View back) {
this.mFrontView = front;
this.mBackView = back;
this.mBackView.setVisibility(View.GONE);
}
#Override
public void onAnimationUpdate(final ValueAnimator animation) {
final float value = animation.getAnimatedFraction();
final float scaleValue = 0.625f + (1.5f * (value - 0.5f) * (value - 0.5f));
if(value <= 0.5f){
this.mFrontView.setRotationY(180 * value);
this.mFrontView.setScaleX(scaleValue);
this.mFrontView.setScaleY(scaleValue);
if(mFlipped){
setStateFlipped(false);
}
} else {
this.mBackView.setRotationY(-180 * (1f- value));
this.mBackView.setScaleX(scaleValue);
this.mBackView.setScaleY(scaleValue);
if(!mFlipped){
setStateFlipped(true);
}
}
}
private void setStateFlipped(boolean flipped) {
mFlipped = flipped;
this.mFrontView.setVisibility(flipped ? View.GONE : View.VISIBLE);
this.mBackView.setVisibility(flipped ? View.VISIBLE : View.GONE);
}
}
That's it!
After this setup you can flip the views by calling
mFlipAnimator.start();
and reverse the flip by calling
mFlipAnimator.reverse();
If you want to check if the view is flipped, implement and call this function:
private boolean isFlipped() {
return mFlipAnimator.getAnimatedFraction() == 1;
}
You can also check if the view is currently flipping by implementing this method:
private boolean isFlipping() {
final float currentValue = mFlipAnimator.getAnimatedFraction();
return (currentValue < 1 && currentValue > 0);
}
You can combine the above functions to implement a nice function to toggle the flip, depending on if it is flipped or not:
private void toggleFlip() {
if(isFlipped()){
mFlipAnimator.reverse();
} else {
mFlipAnimator.start();
}
}
That's it! Simple and easy. Enjoy!

I have created a simple program for creating flip of view like :
In Activity you have to create this method, for adding flip_rotation in view.
private void applyRotation(View view)
{
final Flip3dAnimation rotation = new Flip3dAnimation(view);
rotation.applyPropertiesInRotation();
view.startAnimation(rotation);
}
for this, you have to copy main class used to provide flip_rotation.
import android.graphics.Camera;
import android.graphics.Matrix;
import android.util.Log;
import android.view.View;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.Animation;
import android.view.animation.Transformation;
public class Flip3dAnimation extends Animation {
private final float mFromDegrees;
private final float mToDegrees;
private final float mCenterX;
private final float mCenterY;
private Camera mCamera;
public Flip3dAnimation(View view) {
mFromDegrees = 0;
mToDegrees = 720;
mCenterX = view.getWidth() / 2.0f;
mCenterY = view.getHeight() / 2.0f;
}
#Override
public void initialize(int width, int height, int parentWidth,
int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
mCamera = new Camera();
}
public void applyPropertiesInRotation()
{
this.setDuration(2000);
this.setFillAfter(true);
this.setInterpolator(new AccelerateInterpolator());
}
#Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
final float fromDegrees = mFromDegrees;
float degrees = fromDegrees
+ ((mToDegrees - fromDegrees) * interpolatedTime);
final float centerX = mCenterX;
final float centerY = mCenterY;
final Camera camera = mCamera;
final Matrix matrix = t.getMatrix();
camera.save();
Log.e("Degree",""+degrees) ;
Log.e("centerX",""+centerX) ;
Log.e("centerY",""+centerY) ;
camera.rotateY(degrees);
camera.getMatrix(matrix);
camera.restore();
matrix.preTranslate(-centerX, -centerY);
matrix.postTranslate(centerX, centerY);
}
}

The tutorial or the link by om252345 don't produce believable 3D flips. A simple rotation on the y-axis isn't what's done in iOS. The zoom effect is also needed to create that nice flip feel. For that, take a look at this example.
There is also a video here.

One of the better solution to flip the image with out use of the resource animation , is as follow:-
ObjectAnimator animation = ObjectAnimator.ofFloat(YOUR_IMAGEVIEW, "rotationY", 0.0f, 360f); // HERE 360 IS THE ANGLE OF ROTATE, YOU CAN USE 90, 180 IN PLACE OF IT, ACCORDING TO YOURS REQUIREMENT
animation.setDuration(500); // HERE 500 IS THE DURATION OF THE ANIMATION, YOU CAN INCREASE OR DECREASE ACCORDING TO YOURS REQUIREMENT
animation.setInterpolator(new AccelerateDecelerateInterpolator());
animation.start();

The simplest way to do it is using ViewPropertyAnimator
mImageView.animate().rotationY(360f);
Using the fluent interface you can build more complex and exciting animation.
E.g. you can enable hardware acceleration just call withLayer() method(API 16). More here
If you want to figure out how to create 3d flick animation, please follow here and here
I implemended my own solution only for a research. It includes: cancelation, accelleration, support API >= 15 and is based on Property Animation.
The entire animation includes 4 parts, 2 for each side.
Every objectAnimator has a listener that defines current animation index and represents an image in the onAnimationStart and current play time value in the onAnimationCancel.
It looks like
mQuarterAnim1.addListener(new AnimatorListenerAdapter() {
#Override
public void onAnimationStart(Animator animation) {
mQuarterCurrentAnimStartIndex = QUARTER_ANIM_INDEX_1;
mImageView.setImageResource(mResIdFrontCard);
}
#Override
public void onAnimationCancel(Animator animation) {
mQuarterCurrentAnimPlayTime = ((ObjectAnimator) animation).getCurrentPlayTime();
}
});
For start set call
mAnimatorSet.play(mQuarterAnim1).before(mQuarterAnim2)
If AnimatorSet was canceled we can calculate delta and run the reverse animation relying on the current index animation and the current play time value.
long degreeDelta = mQuarterCurrentAnimPlayTime * QUARTER_ROTATE / QUARTER_ANIM_DURATION;
if (mQuarterCurrentAnimStartIndex == QUARTER_ANIM_INDEX_1) {
mQuarterAnim4.setFloatValues(degreeDelta, QUARTER_FROM_1);
mQuarterAnim4.setDuration(mQuarterCurrentAnimPlayTime);
mAnimatorSet.play(mQuarterAnim4);
}
A full code snippet you can find here

Just put the view which you're going to animate it in place of viewToFlip.
ObjectAnimator flip = ObjectAnimator.ofFloat(viewToFlip, "rotationY", 0f, 360f); // or rotationX
flip.setDuration(2000); // 2 seconds
flip.start();

Adding to A. Steenbergen's great answer. When flipping the same view (updating a TextView for example) I removed the View.Visibility change in the constructor in order to keep the transition smoother.
public FlipListener(final View front, final View back) {
this.mFrontView = front;
this.mBackView = back;
}