Bones: head fallback for headcrab black/fast

- head lookup now accepts head-like bone names (teeth, mouth, jaw, face, eye,
  front, snout, beak) after the HITGROUP_HEAD check
  (headcrabblack: HCblack.teeth; headcrab/fast: HCfast.wiggle_front)
- final fallback is the model's first hitbox center for non-humanoids with
  no head information at all

1 files changed, 23 insertions, 4 deletions

diff --git a/src/bones.cpp b/src/bones.cpp
index 12c7406..1940449 100644
--- a/src/bones.cpp
+++ b/src/bones.cpp
@@ -168,6 +168,18 @@ static bool contains_ci(const char *hay, const char *needle) {
   return false;
 }
 
+// Models without a humanoid head: headcrabs use teeth/front bones, others may
+// expose only eye/jaw/mouth names. The fallback is the first hitbox center.
+static bool head_like_name(const char *n) {
+  static const char *patterns[] = {"head",  "teeth", "mouth", "jaw",
+                                   "face",  "eye",   "front", "snout",
+                                   "beak",  nullptr};
+  for (int i = 0; patterns[i]; i++)
+    if (contains_ci(n, patterns[i]))
+      return true;
+  return false;
+}
+
 static bool hitbox_world(const BoneEntry *e, const Hitbox &b, Vector &out) {
   if (b.bone < 0 || b.bone >= e->count)
     return false;
@@ -423,8 +435,8 @@ bool hitbox_center(int idx, const char *name, Vector &out) {
 }
 
 // Head position with fallbacks, because several HL2 models have no hitbox
-// names: exact "head" hitbox -> hitbox whose bone name contains "head" ->
-// head bone origin. Dumps the hitbox set once for diagnosis.
+// names: exact "head" hitbox -> HITGROUP_HEAD hitbox -> head-like bone name
+// (teeth/front/jaw/eye/...) -> first hitbox center. Dumps the hitbox set once.
 bool head_position(int idx, Vector &out) {
   BoneEntry *e = find_entry(idx);
   if (!e || !e->valid || !e->hdr)
@@ -449,15 +461,22 @@ bool head_position(int idx, Vector &out) {
       if (boxes[i].bone < 0 || boxes[i].bone >= e->count)
         continue;
       const char *bn = bone_name_raw(e->hdr, boxes[i].bone);
-      if (bn && contains_ci(bn, "head"))
+      if (bn && head_like_name(bn))
         return hitbox_world(e, boxes[i], out);
     }
   }
   for (int i = 0; i < e->count; i++) {
     const char *bn = bone_name_raw(e->hdr, i);
-    if (bn && contains_ci(bn, "head"))
+    if (bn && head_like_name(bn))
       return bone_pos(idx, i, out);
   }
+  // Last resort for non-humanoid models with unnamed heads/hitboxes: the
+  // first hitbox is the body (still a valid aim point).
+  if (s && s->numhitboxes > 0) {
+    const Hitbox *boxes = hitboxes(s);
+    if (hitbox_world(e, boxes[0], out))
+      return true;
+  }
   return false;
 }