BeltGCodeWriter subclassed GCodeWriter and overrode seven methods, five of them
by copying the base body and changing the transform. The base writer already
carried an axis remap and already branched at each of its seven
coordinate-emission decisions; the subclass did the same branching with a
different transform, and the two copies had begun to drift.
Replace the inheritance with a strategy object owned by GCodeWriter:
CartesianKinematics to_machine = the existing apply_axis_remap; today's base
behaviour, moved rather than changed.
BeltKinematics to_machine = MachineFrameTransform o axis_remap o
BeltBackTransform, plus a world_coordinates variant for
the PA calibration generators.
New: src/libslic3r/GCode/MachineKinematics.{hpp,cpp}, GCode/BeltKinematics.{hpp,cpp}
Deleted: src/libslic3r/BeltGCodeWriter.{hpp,cpp} (341 lines)
Points worth a reviewer's attention:
* The predicate is must_emit_all_axes(), not couples_axes(). The base returns
true for any non-identity remap, including pure permutations that do not
physically couple axes, so the question is "must every axis word be
emitted", not a statement about kinematics.
* Every per-site word-omission branch is preserved. The base deliberately
emits X/Y only, or Z only, or drops Z when its quantised value is unchanged.
The strategy changes which transform applies, never whether words are
omitted.
* set_kinematics() replays the configured remap and build volume onto a newly
installed strategy, because BeltGCode::init_belt_writer runs before
GCode.cpp calls set_axis_remap/set_build_volume_max.
* uses_pointwise_travel_speed() preserves a pre-existing divergence rather
than introducing one: the base travel_to_xyz emits the raw configured travel
speed in its final branch, ignoring the first-layer value computed at the
top, whereas the belt path used the first-layer-aware value throughout. Both
are kept. Unifying them changes feedrates and belongs in its own change.
* The [BELT-DEBUG] block is deleted; it rate-limited itself with a
function-local static thread_local in the hot emission path, and this is the
commit that would otherwise have moved it into shared code.
This commit is intended to preserve existing export output. That is reviewed by
construction -- each emission site keeps its own omission branch and each policy
divergence is preserved -- and is NOT verified against a G-code diff corpus.
Building that corpus is the outstanding work here.
Two API-equivalence exceptions, neither reachable by any caller today:
* Belt kinematics with no plane pointer installed, m_is_first_layer true,
initial and normal travel speeds differing, travel_to_xyz() reaching its
final branch: the old belt writer selected the initial-layer speed, the new
writer selects the normal travel speed. The pending-lift and XY-only
branches keep their previous selection.
* Belt kinematics installed without set_force_normal_lift(true) and a
non-normal lift requested: the old belt writer forced a normal lift, the new
writer can take the slope branch.
The PA-pattern generator reaches the writer through explicit travel_to_z() /
travel_to_xy(), not travel_to_xyz() or the lazy/eager lift paths, and normal
belt export installs both the plane and the forced-normal-lift policy, so
neither exception changes output produced today. They are recorded because a
future caller could reach them.
tests/fff_print/test_gcodewriter.cpp was also not compiling before this branch:
it called writer.to_machine_coords(), a method that existed only on
BeltGCodeWriter. It never surfaced because the build targets OrcaSlicer, not
all, and BUILD_TESTS defaults to OFF, so that translation unit was outside every
compile path. Fixed here; the existing 30-degree coordinate assertions are kept
verbatim as the best available regression net.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011jgzj1sf53KMLPweZ8yeUQ
* initial commit
* fix upper bounds for assemblies
* significantly less Z shift issues, still not quite tamped down yet though
* add instrumentation to logs
* finally found the issue
* update printer defaults
