From e20e27fdc30bf020d7e908a39a8393a1a202b3b3 Mon Sep 17 00:00:00 2001
From: Regan Green <regan_green27@hotmail.com>
Date: Thu, 5 Oct 2023 05:22:32 -0400
Subject: [PATCH] Further patch work

---
 LEGO1/decomp.cpp              | 102 +++++++++++++++++++++++++++++++++-
 LEGO1/decomp.h                |  23 +++++---
 LEGO1/mxtransitionmanager.cpp |   6 +-
 3 files changed, 117 insertions(+), 14 deletions(-)

diff --git a/LEGO1/decomp.cpp b/LEGO1/decomp.cpp
index dee2a0a2..f8387f24 100644
--- a/LEGO1/decomp.cpp
+++ b/LEGO1/decomp.cpp
@@ -2,8 +2,106 @@
 
 #include "Windows.h"
 
-// Export "Patch" function (non-mangled name)
+#include <stdio.h>
+
+#ifdef ISLE_BUILD_PATCH
+
+// Managed list class for patches
+static class DecompPatchList
+{
+private:
+  struct DecompPatchNode
+  {
+    DecompPatchNode *next;
+    void *origFunc, *newFunc;
+  } *m_head;
+
+public:
+  DecompPatchList()
+  {
+    // I'm having CRT initialization order issues
+    // with MSVC 4.20, so I'm going to leave m_head
+    // uninitialized. It's static so it should be
+    // zeroed anyways.
+    // m_head = NULL;
+  }
+
+  ~DecompPatchList()
+  {
+    // Delete all nodes
+    for (DecompPatchNode *node = m_head; node != NULL;)
+    {
+      DecompPatchNode *next = node->next;
+      delete node;
+      node = next;
+    }
+  }
+
+  void Add(void *origFunc, void *newFunc)
+  {
+    // Create new node
+    DecompPatchNode *node = new DecompPatchNode;
+    node->origFunc = origFunc;
+    node->newFunc = newFunc;
+    node->next = m_head;
+
+    // Add to head of list
+    m_head = node;
+  }
+
+  void Patch(void *root)
+  {
+    // Go through all nodes
+    for (DecompPatchNode *node = m_head; node != NULL; node = node->next)
+    {
+      // Inject JMP instruction
+      BYTE *location = (BYTE*)((DWORD)root + (DWORD)node->origFunc);
+      BYTE *newFunction = (BYTE*)node->newFunc;
+
+      /*
+      DWORD dwOldProtection;
+      VirtualProtect(location, 5, PAGE_EXECUTE_READWRITE, &dwOldProtection);
+      location[0] = 0xE9; //jmp
+      *((DWORD*)(location + 1)) = (DWORD)(((DWORD)newFunction - (DWORD)location) - 5);
+      VirtualProtect(location, 5, dwOldProtection, &dwOldProtection);
+      */
+
+      BYTE code[5];
+      code[0] = 0xE9; //jmp
+      *((DWORD*)(code + 1)) = (DWORD)(((DWORD)newFunction - (DWORD)location) - 5);
+
+      char buffer[256];
+      sprintf(buffer, "location %p, newFunction %p, origFunc %p, root %p", location, newFunction, node->origFunc, root);
+      MessageBoxA(NULL, buffer, "DecompPatchList", MB_ICONERROR);
+
+      static HANDLE hProcess = GetCurrentProcess();
+      DWORD written = 0;
+      if (WriteProcessMemory(hProcess, location, code, sizeof(code), &written) == FALSE || written != sizeof(code))
+      {
+        // Print error reason
+        sprintf(buffer, "WriteProcessMemory failed: %d", GetLastError());
+        MessageBoxA(NULL, buffer, "DecompPatchList", MB_ICONERROR);
+
+        MessageBoxA(NULL, "Patch failed", "DecompPatchList", MB_ICONERROR);
+      }
+    }
+  }
+} decompPatchList;
+
+// Function called to add a patch to the list of patches
+void DecompPatchAdd(void *origFunc, void *newFunc)
+{
+  // Add to list
+  decompPatchList.Add(origFunc, newFunc);
+}
+
+// Exported "Patch" function
+// This goes through all our added patches and applies them
+// Root is the root address of LEGO1.DLL
 extern "C" __declspec(dllexport) void Patch(void *root)
 {
-  MessageBoxA(NULL, "HELLO", "HELLO", 0);
+  // Apply all patches
+  decompPatchList.Patch(root);
 }
+
+#endif
diff --git a/LEGO1/decomp.h b/LEGO1/decomp.h
index f47a2343..23a849e1 100644
--- a/LEGO1/decomp.h
+++ b/LEGO1/decomp.h
@@ -14,18 +14,25 @@ typedef unsigned int undefined4;
 
 #ifdef ISLE_BUILD_PATCH
 
-class PatchHook
-{
-public:
-  PatchHook(void *p_ourFunc, void *p_origFunc);
-};
+void DecompPatchAdd(void *origFunc, void *newFunc);
 
-#define PATCH_HOOK(ourFunc, origFunc) \
-  static PatchHook _patchHook_##__COUNTER__ ((void *)ourFunc, (void *)origFunc)
+#define DECOMP_METHOD_HOOK(origFunc, cls, method, retv, args) \
+namespace _DecompPatchHook_##__COUNTER__ \
+{ \
+  class DecompPatchHook \
+  { \
+  public: \
+    DecompPatchHook() \
+    { \
+      retv(cls :: *method) args = cls::method; \
+      DecompPatchAdd((void*)origFunc, (void*)&_patchHook); \
+    } \
+  } _patchHook; \
+}
 
 #else
 
-#define PATCH_HOOK(ourFunc, origFunc)
+#define DECOMP_METHOD_HOOK()
 
 #endif
 
diff --git a/LEGO1/mxtransitionmanager.cpp b/LEGO1/mxtransitionmanager.cpp
index c985aaec..ce3cd215 100644
--- a/LEGO1/mxtransitionmanager.cpp
+++ b/LEGO1/mxtransitionmanager.cpp
@@ -153,6 +153,7 @@ MxResult MxTransitionManager::GetDDrawSurfaceFromVideoManager() // vtable+0x14
 MxResult MxTransitionManager::StartTransition(TransitionType p_animationType, MxS32 p_speed,
                                               MxBool p_doCopy, MxBool p_playMusicInAnim)
 {
+  Beep(750, 300);
   if (this->m_transitionType == NOT_TRANSITIONING) {
     if (!p_playMusicInAnim) {
       MxBackgroundAudioManager *backgroundAudioManager = BackgroundAudioManager();
@@ -192,10 +193,7 @@ MxResult MxTransitionManager::StartTransition(TransitionType p_animationType, Mx
   return FAILURE;
 }
 
-void Test()
-{
-  MxResult (MxTransitionManager:: * pfTarget)(MxTransitionManager::TransitionType, MxS32, MxBool, MxBool) = MxTransitionManager::StartTransition;
-}
+DECOMP_METHOD_HOOK(0x1004bb70, MxTransitionManager, StartTransition, MxResult, (MxTransitionManager::TransitionType, MxS32, MxBool, MxBool));
 
 // OFFSET: LEGO1 0x1004c170
 void MxTransitionManager::Transition_Wipe()