From 776d203252af9aee69600cae2b3e04778ace161b Mon Sep 17 00:00:00 2001
From: Oliver Bell <freshollie@gmail.com>
Date: Wed, 17 Sep 2025 00:58:46 +0100
Subject: [PATCH] vc: start vc match

---
 Makefile                    |  6 ++++++
 config.mk                   |  5 +++++
 sa2_japan_vc.sha1           |  1 +
 src/game/stage/item_tasks.c | 30 ++++++++++++++++++++++++++++++
 4 files changed, 42 insertions(+)
 create mode 100644 sa2_japan_vc.sha1

diff --git a/Makefile b/Makefile
index e0610b254..b025020d3 100644
--- a/Makefile
+++ b/Makefile
@@ -203,6 +203,10 @@ FORMAT_H_PATHS   := $(shell find . -name "*.h" ! -path '*/build/*' ! -path '*/ex
 CPPFLAGS ?= $(INCLUDE_CPP_ARGS) -D $(GAME_REGION)
 CC1FLAGS ?= -Wimplicit -Wparentheses -Werror
 
+ifneq ($(GAME_VARIANT), 0)
+	CPPFLAGS += -D $(GAME_VARIANT)
+endif
+
 # These have to(?) be defined this way, because
 # the C-preprocessor cannot resolve stuff like:
 # #if (PLATFORM == gba), where PLATFORM is defined via -D.
@@ -397,6 +401,8 @@ tidy:
 
 japan: ; @$(MAKE) GAME_REGION=JAPAN
 
+japan_vc: ; @$(MAKE) GAME_REGION=JAPAN GAME_VARIANT=VIRTUAL_CONSOLE
+
 europe: ; @$(MAKE) GAME_REGION=EUROPE
 
 sdl: ; @$(MAKE) PLATFORM=sdl
diff --git a/config.mk b/config.mk
index 6356e68a1..56c3db577 100644
--- a/config.mk
+++ b/config.mk
@@ -53,6 +53,7 @@ endif
 # Default game variables
 GAME_REVISION ?= 0
 GAME_REGION   ?= USA
+GAME_VARIANT  ?= 0
 DEBUG         ?= 0
 
 # For gbafix
@@ -92,6 +93,10 @@ endif
 endif
 endif
 
+ifeq ($(GAME_VARIANT), VIRTUAL_CONSOLE)
+  BUILD_NAME := $(BUILD_NAME)_vc
+endif
+
 # Debug
 ifeq ($(DEBUG), 1)
   BUILD_NAME := $(BUILD_NAME)_debug
diff --git a/sa2_japan_vc.sha1 b/sa2_japan_vc.sha1
new file mode 100644
index 000000000..872469d4d
--- /dev/null
+++ b/sa2_japan_vc.sha1
@@ -0,0 +1 @@
+2aa6ee2cf2b0ebfafbea6d6d24165b252a7e329e  sa2_japan_vc.gba
diff --git a/src/game/stage/item_tasks.c b/src/game/stage/item_tasks.c
index 623871fcd..7606146fe 100644
--- a/src/game/stage/item_tasks.c
+++ b/src/game/stage/item_tasks.c
@@ -149,6 +149,9 @@ void Task_Item_Shield_Normal(void)
     if (!(gPlayer.itemEffect & PLAYER_ITEM_EFFECT__INVINCIBILITY)) {
         bool32 b;
         s32 screenX, screenY;
+#ifdef VIRTUAL_CONSOLE
+        u32 r0;
+#endif
 
         screenX = I(gPlayer.qWorldX) - cam->x;
         item->s.x = screenX + gPlayer.unk7C;
@@ -161,6 +164,10 @@ void Task_Item_Shield_Normal(void)
 
         UpdateSpriteAnimation(&item->s);
 
+#ifdef VIRTUAL_CONSOLE
+        r0 = Mod(gStageTime, 6);
+#endif
+
 #ifndef NON_MATCHING
         asm("mov %0, %2\n"
             "and %0, %1\n"
@@ -169,15 +176,38 @@ void Task_Item_Shield_Normal(void)
 
         // Make the compiler "forget" that itemEffect is 0x1
         asm("" : "=r"(itemEffect));
+#ifdef VIRTUAL_CONSOLE
+        {
+            register u32 r2 asm("r2") = 6;
+            r0 &= r2;
+        }
+#endif
 #else
         b = (param & 0x1);
+#ifdef VIRTUAL_CONSOLE
+        r0 &= 6;
 #endif
+#endif
+
+#ifdef VIRTUAL_CONSOLE
+        if ((!r0 && (b != itemEffect)) || (r0 && (b != 0))) {
+#else
         if (((gStageTime & 0x2) && (b != itemEffect)) || (!(gStageTime & 0x2) && (b != 0))) {
+#endif
             DisplaySprite(&item->s);
         }
     }
 }
 
+#ifndef NON_MATCHING
+// Looks like they may have manually edited the rom for the virtual console
+// to keep all the functions in the same alignment as the original rom.
+// Maybe they couldn't reexport the anims?
+#ifdef VIRTUAL_CONSOLE
+asm(".byte 0x00, 0x00, 0x00, 0x00");
+#endif
+#endif
+
 void Task_Item_Shield_Magnetic(void)
 {
     s8 param = ITEMTASK_GET_PLAYER_NUM();