Fix a bug where sometimes MiddleFrame could be reset

src/extensions/anim/animext_hooks.cpp

@@ -327,6 +327,14 @@ DECLARE_PATCH(_AnimClass_AI_Beginning_Patch)
     animtype = this_ptr->Class;
     animtypeext = Extension::Fetch<AnimTypeClassExtension>(animtype);
 
+    /**
+     *  We have flagged that this animation's type needs to have
+     *  its biggest frame recalculated, do that.
+     */
+    if (animtype->Biggest == -1) {
+        animtypeext->Set_Biggest_Frame();
+    }
+
     /**
      *  Stolen bytes/code.
      */

src/extensions/animtype/animtypeext.cpp

@@ -64,7 +64,7 @@ AnimTypeClassExtension::AnimTypeClassExtension(const AnimTypeClass *this_ptr) :
     EndAnimsMinimum(),
     EndAnimsMaximum(),
     EndAnimsDelay(),
-    MiddleFrame(-2)
+    MiddleFrame(-1)
 {
     //if (this_ptr) EXT_DEBUG_TRACE("AnimTypeClassExtension::AnimTypeClassExtension - Name: %s (0x%08X)\n", Name(), (uintptr_t)(This()));
 
@@ -402,7 +402,7 @@ bool AnimTypeClassExtension::Read_INI(CCINIClass &ini)
     /**
      *  #issue-883
      * 
-     *  The "biggest" frame of a animation is frame which should hide all cosmetic
+     *  The "biggest" frame of an animation is frame which should hide all cosmetic
      *  changes to the underlaying ground (e.g. craters) that the animation causes,
      *  so these effects are delayed until this frame is reached. TibSun calculates
      *  this by scanning the entire shape file to find the largest visible frame, but
@@ -414,7 +414,7 @@ bool AnimTypeClassExtension::Read_INI(CCINIClass &ini)
      *  of the shape file. This behavior was observed in Red Alert 2.
      */
     if (This()->Image && This()->Image->Get_Frame_Count() > 0) {
-        MiddleFrame = ini.Get_Int_Clamp(ini_name, "MiddleFrame", -2, This()->Image->Get_Frame_Count() - 1, MiddleFrame);
+        MiddleFrame = ini.Get_Int_Clamp(ini_name, "MiddleFrame", -1, This()->Image->Get_Frame_Count() - 1, MiddleFrame);
     }
 
     IsInitialized = true;
@@ -430,10 +430,9 @@ bool AnimTypeClassExtension::Read_INI(CCINIClass &ini)
  */
 void AnimTypeClassExtension::Set_Biggest_Frame()
 {
-    if (MiddleFrame == -1 && This()->Image && This()->Image->Get_Frame_Count() >= 2) {
+    if (MiddleFrame < 0 && This()->Image && This()->Image->Get_Frame_Count() >= 2) {
         This()->Biggest = This()->Image->Get_Frame_Count() / 2;
-    }
-    else if (MiddleFrame != -2) {
+    } else {
         This()->Biggest = MiddleFrame;
     }
 }

src/extensions/animtype/animtypeext_hooks.cpp

@@ -114,22 +114,19 @@ DECLARE_PATCH(_AnimTypeClass_Get_Image_Data_Assertion_Patch)
 
 
 /**
- *  Sets the biggest frame with our override after Init because it reloads the image.
+ *  Set Biggest to -2 to flag that it needs to be recalculated.
+ *  Ideally, this would be done now, but this is sometimes hit before the extension is
+ *  constructed, and we need it.
  *
  *  @author: ZivDero
  */
-DECLARE_PATCH(_AnimTypeClass_Init_MiddleFrame_Patch)
+DECLARE_PATCH(_AnimTypeClass_Load_Image_Biggest_Patch)
 {
-    AnimTypeClassExtension::All_Set_Biggest_Frame();
-
-    // Reconstruct the epilogue
-    _asm
-    {
-        pop esi
-        pop ebp
-        add esp, 0x204
-        retn
-    }
+    GET_REGISTER_STATIC(AnimTypeClass*, this_ptr, esi);
+
+    this_ptr->Biggest = -1;
+
+    JMP(0x00418B99);
 }
 
 
@@ -148,6 +145,5 @@ void AnimTypeClassExtension_Hooks()
     Patch_Jump(0x00419B40, &AnimTypeClassExt::_Free_Image);
     Patch_Jump(0x004187DB, &_AnimTypeClass_DTOR_Free_Image_Patch);
     Patch_Jump(0x00419C0B, &_AnimTypeClass_SDDTOR_Free_Image_Patch);
-    Patch_Jump(0x004188E6, &_AnimTypeClass_Init_MiddleFrame_Patch);
-    Patch_Jump(0x004189C9, &_AnimTypeClass_Init_MiddleFrame_Patch);
+    Patch_Jump(0x00418B15, &_AnimTypeClass_Load_Image_Biggest_Patch);
 }