// Left mouse button click initiates tracking operation.
protected override void OnMouseLeftButtonDown(MouseButtonEventArgs args)
{
base.OnMouseLeftButtonDown(args);
Point ptMouse = args.GetPosition(viewport);
HitTestResult result = VisualTreeHelper.HitTest(viewport, ptMouse);
// We're only interested in 3D hits.
RayMeshGeometry3DHitTestResult result3d =
result as RayMeshGeometry3DHitTestResult;
if (result3d == null)
{
return;
}
// We're only interested in ModelVisual3D hits.
ModelVisual3D vis3d = result3d.VisualHit as ModelVisual3D;
if (vis3d == null)
{
return;
}
// We're only interested in visuals with translate transforms.
transTracking = vis3d.Transform as TranslateTransform3D;
if (transTracking == null)
{
return;
}
LineRange range;
ViewportInfo.Point2DtoPoint3D(viewport, ptMouse, out range);
pointOriginal = range.PointFromZ(transTracking.OffsetZ);
transOriginal = transTracking.Clone();
isTracking = true;
CaptureMouse();
Focus();
args.Handled = true;
}
