[转]在WorldWind中加入*.x格式的三维模型

2021-01-20 13:12

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标签：archive hive val tst img tiles false path 更新

Nasa支持的WorldWind项目最近推出了1.4RC5版，可以加入三维模型，效果如下图所示：

点击查看大图

WW1.4对XML配置文件增加了许多新的元素，其中ModelFeature就是用来增加三维模型的，如下所示：

xml version="1.0" encoding="utf-8"?>
LayerSet Name="Clart Test" ShowOnlyOneLayer="false" ShowAtStartup="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="LayerSet.xsd">
  ModelFeature ShowAtStartup="true">
    Name>Tiny1Name>
    DistanceAboveSurface>160.0DistanceAboveSurface>
    Latitude>
      Value>39.93Value>
    Latitude>
    Longitude>
      Value>116.400002Value>
    Longitude>
    ScaleFactor>2ScaleFactor>
    MeshFilePath>Data\Model\tiny.xMeshFilePath>
    Orientation>
      RotationX>0.0RotationX>
      RotationY>90.0RotationY>
      RotationZ>90.0RotationZ>
    Orientation>
    MaxViewRange>10000.0MaxViewRange>
    MinViewRange>10MinViewRange>
  ModelFeature>

  ModelFeature ShowAtStartup="true">
    Name>Tiny2Name>
    DistanceAboveSurface>160.0DistanceAboveSurface>
    Latitude>
      Value>39.93Value>
    Latitude>
    Longitude>
      Value>116.410002Value>
    Longitude>
    ScaleFactor>2ScaleFactor>
    MeshFilePath>Data\Model\tiny.xMeshFilePath>
    Orientation>
      RotationX>0.0RotationX>
      RotationY>-90.0RotationY>
      RotationZ>90.0RotationZ>
    Orientation>
    MaxViewRange>10000.0MaxViewRange>
    MinViewRange>10MinViewRange>
  ModelFeature>
LayerSet>

本来在LayerSet.xsd中应该对其进行描术，不过我下载的最新版本中该文件还没有更新，所以在VS2005里对这个XML文件进行编辑时会提示找不到ModelFeature这个元素，不用管它，打开源代码在WorldWind项目里的ConfigurationLoader单元，找到getRenderableFromLayerFile函数，有这样一段代码：

addImageLayersFromXPathNodeIterator(iter.Current.Select("ImageLayer"), parentWorld, parentRenderable);
addQuadTileLayersFromXPathNodeIterator(iter.Current.Select("QuadTileSet"), parentWorld, parentRenderable, cache);
addPathList(iter.Current.Select("PathList"), parentWorld, parentRenderable);
addPolygonFeature(iter.Current.Select("PolygonFeature"), parentWorld, parentRenderable);
addLineFeature(iter.Current.Select("LineFeature"), parentWorld, parentRenderable);
addModelFeature(iter.Current.Select("ModelFeature"), parentWorld, parentRenderable);
addWater(iter.Current.Select("Water"), parentWorld, parentRenderable);
addTiledPlacenameSet(iter.Current.Select("TiledPlacenameSet"), parentWorld, parentRenderable);
addTiledWFSPlacenameSet(iter.Current.Select("TiledWFSPlacenameSet"), parentWorld, parentRenderable);
addIcon(iter.Current.Select("Icon"), parentWorld, parentRenderable, cache);
addScreenOverlays(iter.Current.Select("ScreenOverlay"), parentWorld, parentRenderable, cache);
addChildLayerSet(iter.Current.Select("ChildLayerSet"), parentWorld, parentRenderable, cache);

addExtendedInformation(iter.Current.Select("ExtendedInformation"), parentRenderable);

从这可以看出，源程序已经对ModelFeature提供了支持，而在addModelFeature函数中可以找到所有ModelFeature 的子元素，如“Name”、“Latitude”“Longitude”等。

private static void addModelFeature(XPathNodeIterator iter, World parentWorld, RenderableObjectList parentRenderable)
{
    if (iter.Count > 0)
    {
        while (iter.MoveNext())
        {
            string name = getInnerTextFromFirstChild(iter.Current.Select("Name"));
            string refreshurl = getInnerTextFromFirstChild(iter.Current.Select("RefreshURL"));
            float lat = Convert.ToSingle(getInnerTextFromFirstChild(iter.Current.Select("Latitude")));
            float lon = Convert.ToSingle(getInnerTextFromFirstChild(iter.Current.Select("Longitude")));
            float alt = Convert.ToSingle(getInnerTextFromFirstChild(iter.Current.Select("DistanceAboveSurface")));
            float scaleFactor = Convert.ToSingle(getInnerTextFromFirstChild(iter.Current.Select("ScaleFactor")));
            string meshFilePath = getInnerTextFromFirstChild(iter.Current.Select("MeshFilePath"));

            float rotX = Convert.ToSingle(getInnerTextFromFirstChild(iter.Current.SelectSingleNode("Orientation")
                .Select("RotationX")));
            float rotY = Convert.ToSingle(getInnerTextFromFirstChild(iter.Current.SelectSingleNode("Orientation")
                .Select("RotationY")));
            float rotZ = Convert.ToSingle(getInnerTextFromFirstChild(iter.Current.SelectSingleNode("Orientation")
                .Select("RotationZ")));

            ModelFeature model = new ModelFeature(name, parentWorld
                , meshFilePath, lat, lon, alt,scaleFactor,rotX,rotY,rotZ);
            model.RefreshURL = refreshurl;
            parentRenderable.Add(model);
        }
    }
}

根据这些，我们只要生成一个XML文件放到相应模型（如Earth）的配置文件目录，就可以显示自己的三维模型啦! 技术图片

我做了一个例子，下载后，解压到WorldWind1.4的安装目录（如：D:\Program Files\NASA\World Wind 1.4 ），重新启动程序在图层管理里可以看到一个新的层，如下图所示：