This is a new navigation mode for QgsCameraController which is meant to work
just like the terrain-based navigation mode, but for 3D scenes with globe.
Initially, the new navigation mode can handle:
- zooming in/out with mouse wheel
- orbit around globe when dragging with left mouse button pressed
- left/right/up/down keys to orbit around globe
- shift + left/right keys to change heading angle
- shift + up/down keys to change pitch angle
- page up/page down keys to increase/decrease elevation
For camera pose, we use QgsCameraPose as for "flat" scenes, but the QCamera
is positioned/rotated slightly differently - the main change is that in case
of globe, we use ECEF coordinates of the camera pose's center point, convert
them to lat/lon coordinates in order to set up initial rotation of the camera
so that it is perpendicular to the tangent plane at the given ECEF coordinate.
This introduces a new class QgsGeoTransform (derived from QTransform)
that keeps chunk's translation vector as a QgsVector3D (i.e. in double
coordinates) and if there is a shift of the origin, 3D map scene and
chunk entities react to it by adjusting the underlying QTransform.
Create a small, cheap to copy (non-qobject) class
Qgs3DMapSettingsSnapshot which is designed to store
just cheap properties of Qgs3DMapSettings. Then use this
object wherever possible to avoid accessing the (non-thread
safe) Qgs3DMapSettings object for retrieval of simple
map properties (eg crs, extent, ...)
Refs https://github.com/qgis/QGIS-Enhancement-Proposals/issues/301
The 3D scene's CRS is not necessarily the same as the project's
CRS. For example, it can be "EPSG:3857" if the project's CRS is
geographic.
The stored extent in the settings is always the 3D scene's extent.
See:
b0d1a4f8b1
