Question

我想每隔x秒更改菜单的背景图像。我正在使用libGDX scene2D.ui来制作菜单。 TestScreen类扩展了AbstractScreen，它是一个实现libGDX的Screen类的抽象类。问题：通过堆栈上的Table对象将Image加载到舞台后，将图像引用更改为不同的图像。 Stage.draw（）不关心它是否制作了原始图像的副本。我想将背景保持为Image类并通过stage.draw（）进行渲染。

更复杂的是，如果我在render（）方法中将图像更改为另一个图像，那么image.setVisible（false）也会停止工作。

public class TestScreen extends AbstractScreen {

private Stage stage;
private Image background;
private boolean ChangeBackground = true;
private final float refreshTime = 2.0f; // refresh to new image every 2 seconds.
private float counter = refreshTime;

public TestScreen(Game game) {
    super(game);
}

@Override
public void render(float deltaTime) {
    Gdx.gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);

    if(ChangeBackground){
        counter -= deltaTime;
        if(counter < 0){
            counter = refreshTime;
            // Assets class has the 12 images loaded as "Image" objects already.
            // I simple want to change the reference to other (already loaded in memory images) ...
            // and make stage render the new image.
            background = Assets.instance.wallpapers[(int) (Math.random()*12)];  // The image should change.
            //background.setVisible(false);
        }
    }
    stage.act(deltaTime);
    stage.draw();
}

@Override
public void resize(int width, int height) {
    stage.setViewport(Constants.VIEWPORT_GUI_WIDTH, Constants.VIEWPORT_GUI_HEIGHT, false);
}
@Override
public void show() {
    stage = new Stage();
    Gdx.input.setInputProcessor(stage);
    makeStage();
}
@Override
public void hide() {
    stage.dispose();
}
@Override
public void pause() {   
}

// Builds the Background later and adds it to a stage through a stack.
// This is how it's done in my game. I made this test bench to demonstrate.
private void makeStage() {
    Table BackGroundLayer = new Table();
    background = Assets.instance.wallpapers[(int) (Math.random()*12)];
    BackGroundLayer.add(background);

    Stack layers = new Stack();
    layers.setSize(800, 480);
    layers.add(BackGroundLayer);

    stage.clear();
    stage.addActor(layers);
}

}

Answer 1

Image是Actor的子类。主要区别在于Image内部有Drawable。如果您拨打Drawable来调用stage.draw() draw()，则会Image。您可以使用Image更改Drawable，而不是更改setDrawable(Drawable param);。什么是Drawable？它是实现Drawable接口的任何类，例如TextureRegionDrawable。如果您使用的是TextureRegion，则可以使用此构造函数：TextureRegionDrawable(TextureRegion region);。也许最好将背景图像存储在Drawable数组中，这样每次设置新的Drawable时都不必调用construcor。示例代码：

TextureRegionDrawable[] images = new TextureRegionDrawable[12];
for (int i = 0; i<12; i++) {
    images[i] = new TextureRegionDrawable(Assets.instance.textureRegions[i]);
}

然后在你的渲染中：

if(changeBackground) {
   counter -= delta;
   if (counter < 0) {
       counter = refreshtime
       background.setDrawable(images[(int)(Math.random()*12)]);
   }
}

这应该有效

libgdx background图像更改

1 个答案: