Document ACTOR_FLAG_THROW_ONLY (#2274)

* document ACTOR_FLAG_THROW_ONLY

* flip function name

* add comments

include/z64actor.h

@@ -184,8 +184,9 @@ typedef struct ActorShape {
 // ignores point lights but not directional lights (such as environment lights)
 #define ACTOR_FLAG_IGNORE_POINT_LIGHTS (1 << 22)
 
-//
+// When Player is carrying this actor, it can only be thrown, not dropped/placed.
-#define ACTOR_FLAG_23 (1 << 23)
+// Typically an actor can only be thrown when moving, but this allows an actor to be thrown when standing still.
+#define ACTOR_FLAG_THROW_ONLY (1 << 23)
 
 //
 #define ACTOR_FLAG_24 (1 << 24)

src/overlays/actors/ovl_En_Ishi/z_en_ishi.c

@@ -11,7 +11,7 @@
 #include "quake.h"
 #include "terminal.h"
 
-#define FLAGS ACTOR_FLAG_23
+#define FLAGS ACTOR_FLAG_THROW_ONLY
 
 void EnIshi_Init(Actor* thisx, PlayState* play);
 void EnIshi_Destroy(Actor* thisx, PlayState* play2);

src/overlays/actors/ovl_En_Kusa/z_en_kusa.c

@@ -12,7 +12,7 @@
 #include "assets/objects/object_kusa/object_kusa.h"
 #include "terminal.h"
 
-#define FLAGS (ACTOR_FLAG_4 | ACTOR_FLAG_23)
+#define FLAGS (ACTOR_FLAG_4 | ACTOR_FLAG_THROW_ONLY)
 
 void EnKusa_Init(Actor* thisx, PlayState* play);
 void EnKusa_Destroy(Actor* thisx, PlayState* play2);

src/overlays/actors/ovl_En_Niw/z_en_niw.c

@@ -10,7 +10,7 @@
 #include "terminal.h"
 #include "versions.h"
 
-#define FLAGS (ACTOR_FLAG_4 | ACTOR_FLAG_23)
+#define FLAGS (ACTOR_FLAG_4 | ACTOR_FLAG_THROW_ONLY)
 
 void EnNiw_Init(Actor* thisx, PlayState* play);
 void EnNiw_Destroy(Actor* thisx, PlayState* play);

src/overlays/actors/ovl_Obj_Tsubo/z_obj_tsubo.c

@@ -9,7 +9,7 @@
 #include "assets/objects/gameplay_dangeon_keep/gameplay_dangeon_keep.h"
 #include "assets/objects/object_tsubo/object_tsubo.h"
 
-#define FLAGS (ACTOR_FLAG_4 | ACTOR_FLAG_23)
+#define FLAGS (ACTOR_FLAG_4 | ACTOR_FLAG_THROW_ONLY)
 
 void ObjTsubo_Init(Actor* thisx, PlayState* play);
 void ObjTsubo_Destroy(Actor* thisx, PlayState* play2);

src/overlays/actors/ovl_player_actor/z_player.c

@@ -7423,20 +7423,29 @@ void func_8083EA94(Player* this, PlayState* play) {
     Player_AnimPlayOnce(play, this, GET_PLAYER_ANIM(PLAYER_ANIMGROUP_throw, this->modelAnimType));
 }
 
-s32 func_8083EAF0(Player* this, Actor* actor) {
+/**
-    if ((actor != NULL) && !(actor->flags & ACTOR_FLAG_23) &&
+ * Checks if an actor can be thrown or dropped.
+ * It is assumed that the `actor` argument is the actor currently being carried.
+ *
+ * @return true if it can be thrown, false if it can be dropped.
+ */
+s32 Player_CanThrowCarriedActor(Player* this, Actor* actor) {
+    // If the actor arg is null, true will be returned.
+    // It doesn't make sense for a non-existent actor to be thrown or dropped, so
+    // the safety check should happen before this function is even called.
+    if ((actor != NULL) && !(actor->flags & ACTOR_FLAG_THROW_ONLY) &&
         ((this->speedXZ < 1.1f) || (actor->id == ACTOR_EN_BOM_CHU))) {
-        return 0;
+        return false;
     }
 
-    return 1;
+    return true;
 }
 
 s32 Player_ActionHandler_9(Player* this, PlayState* play) {
     if ((this->stateFlags1 & PLAYER_STATE1_CARRYING_ACTOR) && (this->heldActor != NULL) &&
         CHECK_BTN_ANY(sControlInput->press.button, BTN_A | BTN_B | BTN_CLEFT | BTN_CDOWN | BTN_CRIGHT)) {
         if (!func_80835644(play, this, this->heldActor)) {
-            if (!func_8083EAF0(this, this->heldActor)) {
+            if (!Player_CanThrowCarriedActor(this, this->heldActor)) {
                 Player_SetupAction(play, this, Player_Action_808464B0, 1);
                 Player_AnimPlayOnce(play, this, GET_PLAYER_ANIM(PLAYER_ANIMGROUP_put, this->modelAnimType));
             } else {
@@ -10897,7 +10906,7 @@ void Player_UpdateInterface(PlayState* play, Player* this) {
                 } else if ((this->stateFlags1 & PLAYER_STATE1_CARRYING_ACTOR) && (this->getItemId == GI_NONE) &&
                            (heldActor != NULL)) {
                     if ((this->actor.bgCheckFlags & BGCHECKFLAG_GROUND) || (heldActor->id == ACTOR_EN_NIW)) {
-                        if (func_8083EAF0(this, heldActor) == 0) {
+                        if (!Player_CanThrowCarriedActor(this, heldActor)) {
                             doAction = DO_ACTION_DROP;
                         } else {
                             doAction = DO_ACTION_THROW;