Libgdx滚动线的背景外观

Question

I create a background using Inkscape and i use 2 same images of this background to show a moving background but a line appear between them when i run the game, any solutions ?

Picture for the problem in a background the line appears and disappears

Picture for the problem in another background ; the repeat of background is clear

To clarify more this is my Background code :

public class Background extends Actor {


       private final TextureRegion textureRegion;
        private Rectangle textureRegionBounds1;
        private Rectangle textureRegionBounds2;
        private int speed = 70;

        public Background() {
            textureRegion = new TextureRegion(new Texture(Gdx.files.internal(Constants.BACKGROUND_IMAGE_PATH)));
            textureRegionBounds1 = new Rectangle(-800/2, 0, 800,480);
            textureRegionBounds2 = new Rectangle(800/2, 0, 800, 480);
        }

        @Override
        public void act(float delta) {
            if (leftBoundsReached(delta)) {
                resetBounds();
            } else {
                updateXBounds(-delta);
            }
        }

         @Override
        public void draw(Batch batch, float parentAlpha) {
            super.draw(batch, parentAlpha);
            batch.draw(textureRegion, textureRegionBounds1.x, textureRegionBounds1.y, 800,480);
            batch.draw(textureRegion, textureRegionBounds2.x, textureRegionBounds2.y, 800,480);
        }

        private boolean leftBoundsReached(float delta) {
            return (textureRegionBounds2.x - (delta * speed)) <= 0;
        }

        private void updateXBounds(float delta) {
            textureRegionBounds1.x += delta * speed;
            textureRegionBounds2.x += delta * speed;
        }

        private void resetBounds() {
            textureRegionBounds1 = textureRegionBounds2;
            textureRegionBounds2 = new Rectangle(800, 0, 800, 480);
        }

    }

in GameStage class Camera settings :

...
        private static final int VIEWPORT_WIDTH = 800;
        private static final int VIEWPORT_HEIGHT = 480;
...
     public GameStage(){
            super(new ScalingViewport(Scaling.stretch, VIEWPORT_WIDTH, VIEWPORT_HEIGHT,
                    new OrthographicCamera(VIEWPORT_WIDTH, VIEWPORT_HEIGHT)));
            Gdx.input.setInputProcessor(this);
           // renderer = new Box2DDebugRenderer();
            setUpWorld();
            setupCamera();

      }
...
private void setupCamera() {
        camera = new OrthographicCamera(VIEWPORT_WIDTH, VIEWPORT_HEIGHT);
        camera.position.set(camera.viewportWidth / 2, camera.viewportHeight / 2, 0f);
        camera.update();
    }
...

Answer 1

You are probably calculating wrong because you got a column of black dots on right.

Be careful if you are calculating acording to right of the screen so its not will be width. It will be width-1 because x starting with a zero.

But this is not only error you have. But i cant guess other errors from just a picture. It would be better if you provide some cod, filters you apply or original texture that you used.

Answer 2

Your resetBounds() method introduces error in the spacing between the two rectangular regions. When leftBoundsReached() returns true, the position of your region 2 bounds is not going to be an exact multiple of 400 or 800 or whatever spacing you're using. But resetBounds() creates a new set of bounds that are exactly at x = 800.

I would suggest something like this:

    private void resetBounds() {
        Rectangle tmp = textureRegionBounds1;
        textureRegionBounds1 = textureRegionBounds2;
        textureRegionBounds2 = tmp;
        textureRegionBounds2.x = textureRegionBounds1.x + textureRegionBounds1.width;
    }

By the way, I think your act method will produce a possibly visible stutter whenever the left bounds are reached, because you don't move the background on that frame. The background should be moved on every frame regardless if it's time to skip a rectangle over.