[Virtual Point Clouds] Add combobox to adjust the switching between rendering overview only and sub index rendering (Request in QGIS) #10731
Description
Request for documentation
From pull request qgis/QGIS#64351
Author: @ViperMiniQ
QGIS version: 4.0
[Virtual Point Clouds] Add combobox to adjust the switching between rendering overview only and sub index rendering
PR Description:
This PR adds a combobox that controls the point of switching between rendering overview only and rendering a sub index of the VPC.
Users are presented with 4 options (adding the actual value of the option in the brackets, it is subject to change based on the feedback once in the wild): Later (0.5), Normal (1.0), Earlier (2.0), Much earlier (5.0).
On 2D map canvas, if the average extent width of the sub indexes multiplied by the value from the combobox is higher than the viewable map canvas, a sub index is loaded, otherwise overview only gets rendered.
For the 3D Map, we calculate the screen space error (SSE) - https://github.com/qgis/QGIS/blob/de30659865a24d0855eed8850675ab0181ee19c0/src/3d/qgs3dutils.cpp#L881-L905 and compare it against the fixed value of 0.2 divided by the combobox value.
One change is that when all the sub indexes are shown in the 3D Map, we disable overview rendering to save resources.