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.
When a FlowContainer had a TextureRect child using any of the EXPAND_FIT_* expand modes, it could crash when changing the FlowContainer's minimum size, or that of its children. This was due to the TextureRect resizing in FlowContainer::_resort, updating its minimum size, and triggering another _resort. If the TextureRect's minimum size changed in a way that caused any of the FlowContainer's children to be put on a different line, it could repeatedly cause _resort to be called again, moving the children back and forth between the old and new lines.
This change is for FlowContainer::_resort to give a warning for TextureRects with EXPAND_FIT_* expand modes when multiple lines are used, and just keep the TextureRect size the same in that case. This is similar to the check added to AspectRatioContainer in godotengine#73396, but attempting to still support it in FlowContainer when possible. In the case where the TextureRect is forced to stay the same size, there may be some overlap between the FlowContainer's children, but should no longer crash.
Prior to this fix, scrolling via mouse drag on touchscreen devices, and
drag&drop operation on a `TreeItem` element would conflict with each other
preventing the drag scroll from being released when the mouse button is
released.
The issue is addressed by disabling drag&drop when drag scrolling is ongoing.
Fixes that NavigationPolygon did not update in all cases because the internal NavigationMesh was not always unref and freed which blocked creating a new mesh later if nothing else freed it.
