private void CreateScene()
{
DisposeScene();
_ellipsoid = new TessellatedGlobe();
_ellipsoid.Shape = _globeShape;
_ellipsoid.NumberOfSlicePartitions = 64;
_ellipsoid.NumberOfStackPartitions = 32;
///////////////////////////////////////////////////////////////////
// 计算椭球网格
Mesh mesh = GeographicGridEllipsoidTessellator.Compute(_globeShape,
64, 32, GeographicGridEllipsoidVertexAttributes.Position);
// 创建椭球网格线框显示对象
_wireframe = new Wireframe(_window.Context, mesh);
_wireframe.Width = 2;
///////////////////////////////////////////////////////////////////
// 创建坐标轴显示对象
_axes = new Axes();
_axes.Length = 1.5;
_axes.Width = 3;
///////////////////////////////////////////////////////////////////
// 计算p点椭球表面坐标
Vector3D p = _globeShape.ToVector3D(new Geodetic3D(0, Trig.ToRadians(45), 0));
// 计算p点地理法线向量
Vector3D deticNormal = _globeShape.GeodeticSurfaceNormal(p);
// 计算p点地心法线向量
Vector3D centricNormal = Ellipsoid.CentricSurfaceNormal(p);
double normalLength = _globeShape.MaximumRadius;
// 计算地理法线末端点三维坐标
Vector3D pDetic = p + (normalLength * deticNormal);
Vector3D pCentric = p + (normalLength * centricNormal);
VertexAttributeFloatVector3 positionAttribute = new VertexAttributeFloatVector3("position", 4);
// 创建地理法线段顶点
positionAttribute.Values.Add(p.ToVector3F());
positionAttribute.Values.Add(pDetic.ToVector3F());
// 创建地心法线段顶点
positionAttribute.Values.Add(p.ToVector3F());
positionAttribute.Values.Add(pCentric.ToVector3F());
VertexAttributeRGBA colorAttribute = new VertexAttributeRGBA("color", 4);
// 创建地理法线段顶点颜色
colorAttribute.AddColor(Color.DarkGreen);
colorAttribute.AddColor(Color.DarkGreen);
// 创建地心法线段顶点颜色
colorAttribute.AddColor(Color.DarkCyan);
colorAttribute.AddColor(Color.DarkCyan);
// 创建地理/地心发现段图形显示元语
Mesh polyline = new Mesh();
polyline.PrimitiveType = PrimitiveType.Lines;
polyline.Attributes.Add(positionAttribute);
polyline.Attributes.Add(colorAttribute);
_normals = new Polyline();
_normals.Set(_window.Context, polyline);
_normals.Width = 3;
///////////////////////////////////////////////////////////////////
Font font = new Font("Arial", 24);
IList <Bitmap> labelBitmaps = new List <Bitmap>(2);
labelBitmaps.Add(Device.CreateBitmapFromText("Geodetic", font));
labelBitmaps.Add(Device.CreateBitmapFromText("Geocentric", font));
font.Dispose();
// 创建纹理压缩对象？
TextureAtlas atlas = new TextureAtlas(labelBitmaps);
_labels = new BillboardCollection(_window.Context, 2);
_labels.Texture = Device.CreateTexture2D(atlas.Bitmap, TextureFormat.RedGreenBlueAlpha8, false);
_labels.Add(new Billboard()
{
Position = pDetic,
// 取第一个纹理
TextureCoordinates = atlas.TextureCoordinates[0],
Color = Color.DarkGreen,
HorizontalOrigin = HorizontalOrigin.Right,
VerticalOrigin = VerticalOrigin.Bottom
});
_labels.Add(new Billboard()
{
Position = pCentric,
// 取第二个纹理
TextureCoordinates = atlas.TextureCoordinates[1],
Color = Color.DarkCyan,
HorizontalOrigin = HorizontalOrigin.Right,
VerticalOrigin = VerticalOrigin.Bottom
});
atlas.Dispose();
///////////////////////////////////////////////////////////////////
Vector3D east = Vector3D.UnitZ.Cross(deticNormal);
Vector3D north = deticNormal.Cross(east);
// 创建p点切平面
_tangentPlane = new Plane(_window.Context);
_tangentPlane.Origin = p;
_tangentPlane.XAxis = east;
_tangentPlane.YAxis = north;
_tangentPlane.OutlineWidth = 3;
}