Class Scene

CodenameOne/src/com/codename1/gaming/Scene.java:36–113

/// the contents change) and applies a camera offset that scrolls the whole scene.
/// `#update(double)` advances every sprite (driving `AnimatedSprite` playback).
public class Scene {
    private final List sprites = new ArrayList();
    private boolean sortDirty;
    private int cameraX;
    private int cameraY;

    private static final Comparator Z_ORDER = new ZComparator();

    private static final class ZComparator implements Comparator {
        @Override
        public int compare(Object a, Object b) {
            int za = ((Sprite) a).getZOrder();
            int zb = ((Sprite) b).getZOrder();
            return za < zb ? -1 : (za > zb ? 1 : 0);
        }
    }

    /// Adds a sprite to the scene.
    public void add(Sprite s) {
        sprites.add(s);
        sortDirty = true;
    }

    /// Removes a sprite from the scene.
    public void remove(Sprite s) {
        sprites.remove(s);
    }

    /// Removes all sprites.
    public void clear() {
        sprites.clear();
    }

    public int size() {
        return sprites.size();
    }

    public Sprite get(int index) {
        return (Sprite) sprites.get(index);
    }

    /// Advances every sprite in the scene by calling `Sprite#onUpdate(double)`. Do
    /// not add or remove sprites from within `onUpdate`; defer that to the next frame.
    public void update(double deltaSeconds) {
        for (Object sprite : sprites) {
            ((Sprite) sprite).onUpdate(deltaSeconds);
        }
    }

    /// Sorts the sprites by z-order if the contents changed. Called by the renderer
    /// before drawing.
    void ensureSorted() {
        if (sortDirty) {
            Collections.sort(sprites, Z_ORDER);
            sortDirty = false;
        }
    }