#16195 added slope.up_direction to the SlopeDetection uniform struct of
phong.vs (110 and 140) but not to phong.fs, so the two stages declared the
uniform with different types and the program failed to link: "unable to
load shaders: phong" at startup, and studio lighting / realistic phong
rendering fell back. gouraud.fs already carries the member.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Reported: once extruded, a part is hard to read; the lighting says
little about its shape. Both lights of the object shaders sit near the
camera, so the sides of a part come out in almost the same tone, and
nothing marks where one face ends and the next begins.
- The phong shader gains a studio lighting model, chosen by a new
lighting_model uniform: a sky/ground hemisphere in world space (up
faces cool and bright, down faces warm and dark), a key light from the
upper left and a weak fill from the right, a plastic-like highlight,
and a darker base with a faint sheen toward the silhouette so curved
faces read as round. GLCanvas3D::set_studio_lighting() makes a canvas
draw its objects with it whatever the realistic-view preferences; only
the Design canvas turns it on. Every canvas sets the uniform on each
use, 0 for the slicer's, so they render as before.
- Every B-rep edge of a body is drawn as a thin dark line over it, depth
tested and pulled a few pixels toward the eye so it wins against the
faces meeting at it and hides behind the faces in front. The seam of a
closed surface and degenerate edges are left out
(GeometryEngine::display_edges). Edges are sampled once per shape and
kept across recomputes that leave a body unchanged; bodies faded by
body focus get fainter edges, and a dress-up previewing its result
alone hides them with the bodies.
Tests: display_edges gives a box its 12 edges at their lengths, a
cylinder its two round rims without the seam, a cone its base rim
without the seam or the apex.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QK4VgguuCAk2hZLWgcjJb9
