Vanilla bugfix, Deku Shield burning drop crash (#6810)

soh/soh/Enhancements/AlwaysOnFixes.cpp

@@ -3,6 +3,9 @@
 #include "soh/ShipInit.hpp"
 
 extern "C" {
+#include "macros.h"
+#include "functions.h"
+#include "variables.h"
 extern void Player_UseItem(PlayState*, Player*, s32);
 extern PlayState* gPlayState;
 }
@@ -20,6 +23,17 @@ void RegisterFixOutsideTotCrash() {
     });
 }
 
+// Vanilla bug: `Actor_Item_Shield` (dropped Deku Shield when burning) assumes that segment 12
+// contains Link display list `gCullBackDList`. If an actor is drawn between player and shield
+// that uses segment 12 (such as Jabu-Jabu tentacles), the game will crash on Deku Shield drop.
+// Fix: Re-set segment 12 to the required display list.
+void RegisterFixDekuShieldDropCrash() {
+    COND_VB_SHOULD(VB_ITEMSHIELD_DRAW, true, {
+        GraphicsContext* __gfxCtx = gPlayState->state.gfxCtx;
+        gSPSegment(POLY_OPA_DISP++, 0x0C, (uintptr_t)SEGMENTED_TO_VIRTUAL(gCullBackDList));
+    });
+}
+
 // Vanilla bug: If Hookshot doesn't spawn, player is softlocked. (eg. use as child, no memory left)
 // Fix: Change item to none if no spawn. (Ranged weapon state is removed by `Player_InitItemAction`)
 void RegisterPreventHookshotNoSpawnSoftlock() {
@@ -45,5 +59,6 @@ void RegisterPreventHookshotParentSoftlock() {
 }
 
 static RegisterShipInitFunc initFuncFixOutsideTotCrash(RegisterFixOutsideTotCrash, { "" });
+static RegisterShipInitFunc initFuncFixDekuShieldDropCrash(RegisterFixDekuShieldDropCrash, { "" });
 static RegisterShipInitFunc initFuncHookshotNospawnSoftlock(RegisterPreventHookshotNoSpawnSoftlock, { "" });
 static RegisterShipInitFunc initFuncHookshotParentSoftlock(RegisterPreventHookshotParentSoftlock, { "" });

soh/soh/Enhancements/game-interactor/vanilla-behavior/GIVanillaBehavior.h

@@ -3066,6 +3066,14 @@ typedef enum {
     // - `*EnItem00`
     VB_ITEM00_KILL,
 
+    // #### `result`
+    // ```c
+    // true
+    // ```
+    // #### `args`
+    // - none
+    VB_ITEMSHIELD_DRAW,
+
     // #### `result`
     // ```c
     // true

soh/src/overlays/actors/ovl_Item_Shield/z_item_shield.c

@@ -7,6 +7,8 @@
 #include "vt.h"
 #include "z_item_shield.h"
 #include "objects/object_link_child/object_link_child.h"
+#include "soh/Enhancements/game-interactor/GameInteractor.h"
+#include "soh/Enhancements/game-interactor/GameInteractor_Hooks.h"
 
 #define FLAGS ACTOR_FLAG_UPDATE_CULLING_DISABLED
 
@@ -221,6 +223,7 @@ void ItemShield_Draw(Actor* thisx, PlayState* play) {
     if (!(this->unk_19C & 2)) {
         OPEN_DISPS(play->state.gfxCtx);
         Gfx_SetupDL_25Opa(play->state.gfxCtx);
+        GameInteractor_Should(VB_ITEMSHIELD_DRAW, true);
         gSPMatrix(POLY_OPA_DISP++, MATRIX_NEWMTX(play->state.gfxCtx), G_MTX_NOPUSH | G_MTX_LOAD | G_MTX_MODELVIEW);
         gSPDisplayList(POLY_OPA_DISP++, SEGMENTED_TO_VIRTUAL(gLinkChildDekuShieldDL));
         CLOSE_DISPS(play->state.gfxCtx);