libgdx background图像更改

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,则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.的子类Actor.主要区别在于,内部Image有一个Drawable.这Drawable如果调用被绘制stage.draw(),它调用draw()的Image.而不是改变Image你可以改变Drawable使用setDrawable(Drawable param);.什么是Drawable？它是实现Drawable接口的任何类,例如TextureRegionDrawable.如果你正在使用TextureRegions,你可以使用这个构造函数:TextureRegionDrawable(TextureRegion region);.也许最好将背景图像存储在Drawable数组中,这样每次设置新的时都不必调用construcor Drawable.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)]);
   }
}

这应该工作