View-dependent display refinement: finer curved faces and edges as you zoom in (#1320) (#1425)

* View-dependent display refinement: bodies seen up close are drawn from finer display plans (#1320)

Each frame the viewport works out every shown body's screen-space error (the display
quality's chord tolerance in pixels where the body is nearest the eye) and picks a
refinement step past the chosen display quality, each halving the chord, with hysteresis.
Steps are planned off the UI thread and swapped in when ready, within a triangle budget
and a cache size. Faces (GPU plan or CPU mesh), edges, silhouettes and highlights of a
refined body all come from the refined plan, so a highlight stays on the drawn triangles.
Planned bodies are chunked by content on the GPU, so a refinement re-evaluates only its
own chunk. Display only: the reference mesh, the B-rep and exports never change.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Display refinement: only collect finished plans while the view stands still, time the choice, keep the web planning one step a frame

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Format

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Keep the Display quality note as it was (the longer one pushed the Colour vision list off the Graphics page)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

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Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

crates/ui-egui/src/lib.rs

@@ -90,6 +90,7 @@ mod file_picker;
 pub use file_picker::FilePickerFuture;
 #[cfg(test)]
 mod blend_arrow_tests;
+pub(crate) mod display_lod;
 #[cfg(test)]
 mod file_load_ui_tests;
 #[cfg(test)]