When the smallest dash / gap element of a linetype pattern would project
below one pixel on screen, the gaps either shimmer as aliasing or vanish
entirely — the user reads the line as solid anyway. Compute the min
non-zero element of `pat0 / pat1` once in the vertex shader, flat-
interpolate it across the instance, and let the fragment stage skip the
arc-length dash test (and the `discard` for gap fragments) when
`min_elem >= u.world_per_pixel` fails. Mirrors the existing hatch-LOD
branch in `hatch.wgsl`; primary win is visual quality at extreme
zoom-out, with a small fragment-shader op saving as a side effect.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Step 3 of the wire pipeline cold-open optimization plan — the biggest
single lever.
Each segment used to upload as 6 vertices × 96 B = 576 B with the segment
payload (pos_a/pos_b/color/half_width/distance/pattern_length/pat0/pat1)
duplicated across all six corners of the quad. Wire pipeline now uploads
one INSTANCE per segment (88 B) and the vertex shader derives `which_end`
and `side` from `@builtin(vertex_index)` against a 6-entry corner table.
Net effect on cold open: ~6.5× less wire vertex memory and PCIe upload,
plus a smaller Vec to allocate and copy on the CPU side.
Wire instance attributes also collapse distance_a / distance_b into a
single mix() inside the vertex shader, so per-segment distance still
interpolates correctly for the GPU-side linetype dash test.
Touches the wire, wire_xray, and face3d-edges draw passes.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
LWDISPLAY (Show Lineweight) flipping the toggle no longer triggers a full
retessellate. `render_style_for` always bakes the entity's resolved (layer-
inherited) lineweight, and the wire shader reads `Uniforms.lwdisplay_enable`
to either honour the per-vertex half_width or collapse the quad to a 1 px line.
Side effect: PDF export now uses the real lineweight regardless of LWDISPLAY,
matching AutoCAD's plot semantics (LWDISPLAY only affects screen render).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
