LibGdx animation using TextureAtlas

Question

I'm trying to load an explosion animation. The animations consists of 16 frames, all saved in the file Explosion.png. In my game, all the images are stored in a texture atlas pack.

So first i got the region that i needed from the class Assets.java

public class Explosion {
    public final AtlasRegion explosion;
    public Explosion (TextureAtlas atlas){
        explosion = atlas.findRegion(Constants.EXPLOSION);
    }
}

Then in my class which will create the explosion, I have the following code:

public Particles(Vector2 position){
    this.position = position;
    startTime = TimeUtils.nanoTime();

    Array<TextureRegion> explosionAnimationTexture = new Array<TextureRegion>();

    TextureRegion region = Assets.instance.explosion.explosion;
    Texture explosionTexture = region.getTexture();

    int ROW = 4;  // rows of sprite sheet image
    int COLUMN = 4;
    TextureRegion[][] tmp = TextureRegion.split(explosionTexture, explosionTexture.getWidth() / COLUMN, explosionTexture.getHeight() / ROW);
    TextureRegion[] frames = new TextureRegion[ROW * COLUMN];
    int elementIndex = 0;
    for (int i = 0; i < ROW; i++) {
        for (int j = 0; j < COLUMN; j++) {
            explosionAnimationTexture.add(tmp[i][j]);
            frames[elementIndex++] = tmp[i][j];
        }
    }

    explosion = new Animation(EXPLOSION_FRAME_DURATION,explosionAnimationTexture , Animation.PlayMode.LOOP_PINGPONG);
}

I'm using 4x4 since I have 16 frame. And inside the render method i got the following:

public void render(SpriteBatch batch){
    float elapsedTime = MathUtils.nanoToSec * (TimeUtils.nanoTime() - startTime);
    TextureRegion walkLoopTexture = explosion.getKeyFrame(elapsedTime);

    batch.draw(
            walkLoopTexture.getTexture(),
            position.x,
            position.y,
            0,
            0,
            walkLoopTexture.getRegionWidth(),
            walkLoopTexture.getRegionHeight(),
            0.3f,
            0.3f,
            0,
            walkLoopTexture.getRegionX(),
            walkLoopTexture.getRegionY(),
            walkLoopTexture.getRegionWidth(),
            walkLoopTexture.getRegionHeight(),
            false,
            false);

}

The animation is working, however the images are loading from the whole atlas file, and not only Explosion.png as specified in step 1.

Answer 1

Code inside your Particles class :

TextureRegion region = Assets.instance.explosion.explosion;
TextureRegion[][] tmp = TextureRegion.split(explosionTexture, explosionTexture.getWidth() / COLUMN, explosionTexture.getHeight() / ROW);

replace with :

TextureRegion[][] tmp = region.split(region.getRegionWidth()/COLUMN,region.getRegionHeight()/ROW);

---

And

draw your Animation using textureRegion instead of his texture so choose appropriate method signature of SpriteBatch for drawing textureRegion.