Recover biped limp and flight pair

docs/object_matching_logs/bipeds_obj_jonas_limp_flight_pair_20260831.md

@@ -0,0 +1,69 @@
+# `bipeds.obj` limp/flight exact pair (2026-08-31)
+
+## Result
+
+Starting from canonical commit `67ccd4929`, this packet integrates two small
+public biped functions from Claude campaign commit `e02971dfd`.  Both were
+unwritten in canonical and both have independently recovered HCEA source.
+
+| Function | Meaningful / padded bytes | Relocations | Normalized SHA-256 |
+|---|---:|---:|---|
+| `_biped_flying_through_air` | `77 / 80` | `2` | `7014e0409e490ffcffd5a41a6c80c0b7ee41e2aaa29ea4e96a0d162f7353d775` |
+| `_biped_stop_limp_body_physics` | `78 / 80` | `2` | `69a454875401694e27644bc9d8c9a26b0cd7ce0092520c1797f60e4c3a1a4e05` |
+| **Packet gain** | **`155 / 160`** | **`4`** | |
+
+`bipeds.obj` advances from **9 exact / 0 residual / 42 unwritten**
+to **11 exact / 0 residual / 40 unwritten**.
+
+## Source and ownership
+
+`biped_stop_limp_body_physics` obtains the typed biped and definition owners,
+checks the definition's limp-body capability and the runtime active bit, then
+clears the canonical object node-matrix and runtime limp flags with
+`TEST_FLAG`/`SET_FLAG`.  The HCEA-authenticated runtime flag name and value are
+kept as the owner-local `_biped_limp_body_physics_active_bit = 5` rather than
+the donor's weaker inferred spelling.
+
+`biped_flying_through_air` returns the natural airborne-tick predicate combined
+with the definition's flying flag and the object's dead flag.  It uses the
+existing `_biped_flying_bit`, `_biped_uses_limp_body_physics_bit`,
+`_object_dead_bit`, and `_object_do_not_recompute_node_matrices_bit` owners;
+there are no raw masks or offsets.
+
+`biped_definitions.h` is included only by the owning C file.  The two correct
+public prototypes already live in `bipeds.h`, so no shared-header edit or
+prototype duplication is introduced.  January COFF records both functions as
+external storage-class-2 function symbols, matching the retained definitions.
+
+The function names, signatures, fields, and logic are corroborated by HCEA
+commit `aa635a70`; January remains authoritative for the PC ABI, COMDAT bytes,
+relocations, and boundaries.
+
+## Deliberate exclusions
+
+The broad donor biped patch is not copied.  `biped_start_limp_body_physics`
+still needs limp-noodle prototype and debug-global ownership; `biped_reset`
+uses an incompatible `depths_of_hell` declaration; and the placement,
+preprocess, raw-layout, and larger physics bodies retain unresolved ABI or
+semantic dependencies.  No source-shaping attribute, inline assembly,
+barrier, representation cast, semantic exception, or parked record is added.
+
+## Validation
+
+- whole-unit gate: `11 exact / 0 residual / 40 unwritten`;
+- direct gates: both functions strict exact at 80 padded bytes and two REL32
+  relocations, to `_object_get_and_verify_type` and `_tag_get`;
+- all nine inherited exact biped functions remain exact;
+- owner object compiles through Ninja;
+- full cache/libcmt/progress/semantic build with the concurrent disjoint AI
+  packet: pass;
+- whole-tree verdict diff: exactly the two biped gains plus the five documented
+  AI gains, with zero unexpected transitions;
+- protected `units.obj`: 189/189;
+- changed-file fake-match scan: zero review leads;
+- tooling tests: 222/222 pass;
+- parked audit: 25 active, zero stale, zero invalid;
+- object-admission state unchanged; `config/symbols.json` parses and
+  `git diff --check` passes.
+
+No push is performed by this packet.

source/units/bipeds.c

@@ -235,10 +235,16 @@ symbols in this file:
 
 #include "cseries.h"
 #include "models/model_animation_definitions.h"
+#include "units/biped_definitions.h"
 #include "units/bipeds.h"
 
 /* ---------- constants */
 
+enum
+{
+	_biped_limp_body_physics_active_bit = 5,
+};
+
 /* ---------- macros */
 
 /* ---------- structures */
@@ -316,4 +322,36 @@ void biped_disconnect_from_structure_bsp(
 	return;
 }
 
+void biped_stop_limp_body_physics(
+	long biped_index)
+{
+	struct biped_datum *biped;
+	struct biped_definition *definition;
+
+	biped = biped_get(biped_index);
+	definition = biped_definition_get(biped->definition_index);
+	if (TEST_FLAG(definition->biped.flags, _biped_uses_limp_body_physics_bit) &&
+		TEST_FLAG(biped->biped.flags, _biped_limp_body_physics_active_bit))
+	{
+		SET_FLAG(biped->object.flags, _object_do_not_recompute_node_matrices_bit, FALSE);
+		SET_FLAG(biped->biped.flags, _biped_limp_body_physics_active_bit, FALSE);
+	}
+
+	return;
+}
+
+boolean biped_flying_through_air(
+	long biped_index)
+{
+	struct biped_datum *biped;
+	struct biped_definition *definition;
+
+	biped = biped_get(biped_index);
+	definition = biped_definition_get(biped->definition_index);
+
+	return biped->biped.airborne_ticks > 3 &&
+		(!TEST_FLAG(definition->biped.flags, _biped_flying_bit) ||
+		TEST_FLAG(biped->object.damage_flags, _object_dead_bit));
+}
+
 /* ---------- private code */