PointPlacemarks 的绘制顺序

Question

有没有办法修复World Wind中PointPlacemarks的绘制顺序？

即使在Placemarks example 中，地标 B 的顺序和音频地标也可以通过在特定缩放级别上移动鼠标来改变：

到目前为止我已经尝试过：

• 将 PointPlacemarks 添加到单独的图层
• 使用RenderableLayer.setRenderables 而不是RenderableLayer.addRenderable
• Related question on World Wind forums

Answer 1

Hacky解决方案（需要修改World Wind源代码）

在gov.nasa.worldwind.render.DrawContextImpl 中将orderedRenderables 从

protected PriorityQueue<OrderedRenderableEntry> orderedRenderables =
    new PriorityQueue<OrderedRenderableEntry>(100, new Comparator<OrderedRenderableEntry>()
    {
        public int compare(OrderedRenderableEntry orA, OrderedRenderableEntry orB)
        {
            double eA = orA.distanceFromEye;
            double eB = orB.distanceFromEye;

            return eA > eB ? -1 : eA == eB ? (orA.time < orB.time ? -1 : orA.time == orB.time ? 0 : 1) : 1;
        }
    });

到

protected Queue<OrderedRenderableEntry> orderedRenderables = new ArrayDeque<>();

（或修改比较器以执行您想要的操作）。这将修复绘图顺序。

替代方案（不需要修改World Wind源代码）

扩展PointPlacemark 并覆盖makeOrderedRenderable()：

public class OrderedPointPlacemark extends PointPlacemark {
    public OrderedPointPlacemark(Position position) {
        super(position);
    }
    @Override
    protected void makeOrderedRenderable(DrawContext dc) {
        super.makeOrderedRenderable(dc);

        if (this.intersectsFrustum(dc) || this.isDrawLine(dc)) {
            dc.pollOrderedRenderables();
            dc.addOrderedSurfaceRenderable(this);
        }
    }
}