Touch code only working at center of screen in my ball game using libgdx

问题

My score does not increment after I touch the ball. It increments only when I touch the ball and its near the center of my screen. When my ball only moves in x axis keeping y constant the touch works fine. But when both are incremented the score increases only when touched at the center.

@Override
public void render () {


    batch.begin();

    Gdx.gl.glClearColor(1,1,1,1);
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

    batch.draw(ball,xposi,yposi,100,100);

    if(gameState==1) {


        if (Gdx.input.justTouched()) {

            tmp = new Vector3(Gdx.input.getX(), Gdx.input.getY(), 0);
            textureBounds = new Rectangle(xposi, yposi, 100, 100);

            if (textureBounds.contains(tmp.x, tmp.y)) {
                Gdx.app.log("Click", "On Ball");
                score++;
                } 
           else {
                Gdx.app.log("Click", "Not on Ball");
                }
            }



        font.draw(batch, String.valueOf(score), 100, 300);
        font.draw(batch, String.valueOf(lives), 200, 300);

        xposi+=velocity;
        yposi+=velocity;

        if (xposi >= xmax - 100) {

            velocity = -velocity;
        } else if (xposi <= xmin) {

            velocity = -velocity;
        }

        if (yposi >= ymax - 100) {

            velocity = -velocity;
        } else if (yposi <= ymin) {

            velocity = -velocity;
        }

        batch.end();
     }
 }

回答1:

In libgdx, when we draw something on screen then the screen origin is bottom left corner but when we detect touch then screen origin is top left corner.

When you deal with horizontal movement then there is no involvement of y coordinate so it's work fine. You detect touch on ball when your ball is in center then the value of Gdx.input.getY() is approximately same to Gdx.graphics.getHeight()-Gdx.input.getY() so sometimes works.

so simple solution is just invert touch coordinate origin to bottom left corner.

tmp = new Vector3(Gdx.input.getX(),Gdx.graphics.getHeight()-Gdx.input.getY(), 0);

Recommendation :

Don't create object in render method like you're creating object of Rectangle and Vector3, create object in show() or create() method and set value to these variable in render() method.

来源：https://stackoverflow.com/questions/42231393/touch-code-only-working-at-center-of-screen-in-my-ball-game-using-libgdx

标签

android

libgdx