Rotation precision when switching from 2D -> 3D and back to 2D

openlayers / ol-cesium

OpenLayers - Cesium integration

http://openlayers.org/ol-cesium/

BSD 2-Clause "Simplified" License

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Rotation precision when switching from 2D -> 3D and back to 2D #306

Open bartvde opened 8 years ago

bartvde commented 8 years ago

So my map has a view with rotation 0. I then switch to 3D view which uses ol3-cesium. When switching back the 2D the rotation is not exactly 0 anymore but 3.043247875922678e-10 is there an explanation for this loss of precision in the rotation of the view?

gberaudo commented 8 years ago

The 2D and 3D views are synchronized using a floating point computation. There is a loss of precision in the rotation and the other view parameters.

What could be done, is to apply the OL3 view constraints when back to 2D:

add a core function containing https://github.com/geoadmin/mf-geoadmin3/blob/master/src/js/GaCesium.js#L170-L175; make sure rotation 0 is handled.
call it in OLCesium.setEnabled(false).

bartvde commented 8 years ago

ah thanks for pointing to this code snippet @gberaudo