On Android the exit logic goes through `Godot#onDestroy()` who attempts to cleanup the engine using the following code:
```
runOnRenderThread {
GodotLib.ondestroy()
forceQuit()
}
```
The issue however is that by the time we ran this code, the render thread has already been paused (but not yet destroyed), and thus `GodotLib.ondestroy()` and `forceQuit()` which are scheduled on the render thread are not executed.
To address this, we instead explicitly request the render thread to exit and block until it does. As part of it exit logic, the render thread has been updated to properly destroy and clean the native instance of the Godot engine, resolving the issue.
On Windows this allows to avoid having to change the owner of the window
after it has been created, which in rare circumstances may cause the
window to bug out.
This is disabling the logic added in #84974 which caused #94416.
That issue still needs to be debugged further, but this works around
the regression and should have minimal usability impact on Android.
Before this change StringName used regular static field
definitions for its mutex, _table, configured and debug_stringname
fields.
Since in the general case the ordering of the static variable and field
initialization and destruction is undefined, it was possible that
the destruction of StringName's static fields happened prior to
the destruction of statically allocated StringName instances.
By changing the static field definitions to inline in string_name.h,
the C++17 standard guarantees the correct initialization and destruction
ordering.
When UVs are mirrored in a mesh, collapsing vertices across the
mirroring seam can significantly reduce quality in a way that is not
apparent to the simplifier. Even if simplifier was given access to UV
data, the coordinates would need to be weighted very highly to prevent
these collapses, which would penalize overall quality of reasonable
models.
Normally, well behaved models with mirrored UVs have tangent data that
is correctly mirrored, which results in duplicate vertices along the
seam. The simplifier automatically recognizes that seam and preserves
its structure; typically models have few edge loops where UV winding is
flipped so this does not affect simplification quality much.
However, pre-processing for LOD data welded vertices when UVs and
normals were close, which welds these seams and breaks simplification,
creating triangles with distorted UVs.
We now take tangent frame sign into account when the input model has
tangent data, and only weld vertices when the sign is the same.
