From 29e7495cdf6e31a431e73af085fd9ff6d67df1de Mon Sep 17 00:00:00 2001
From: CCHyper <73803386+CCHyper@users.noreply.github.com>
Date: Wed, 22 Sep 2021 17:07:28 +0100
Subject: [PATCH] Implements IsEligibleForAllyBuilding for BuildingTypes.

---
 .../buildingtype/buildingtypeext.cpp          |  9 ++-
 src/extensions/buildingtype/buildingtypeext.h |  5 ++
 src/extensions/display/displayext_hooks.cpp   | 71 +++++++++++++++++++
 3 files changed, 83 insertions(+), 2 deletions(-)

diff --git a/src/extensions/buildingtype/buildingtypeext.cpp b/src/extensions/buildingtype/buildingtypeext.cpp
index 03ee7fb79..1644b4397 100644
--- a/src/extensions/buildingtype/buildingtypeext.cpp
+++ b/src/extensions/buildingtype/buildingtypeext.cpp
@@ -46,7 +46,6 @@ ExtensionMap<BuildingTypeClass, BuildingTypeClassExtension> BuildingTypeClassExt
  */
 BuildingTypeClassExtension::BuildingTypeClassExtension(BuildingTypeClass *this_ptr) :
     Extension(this_ptr),
-
     GateUpSound(VOC_NONE),
     GateDownSound(VOC_NONE),
     ProduceCashStartup(0),
@@ -54,7 +53,8 @@ BuildingTypeClassExtension::BuildingTypeClassExtension(BuildingTypeClass *this_p
     ProduceCashDelay(0),
     ProduceCashBudget(0),
     IsStartupCashOneTime(false),
-    IsResetBudgetOnCapture(false)
+    IsResetBudgetOnCapture(false),
+    IsEligibleForAllyBuilding(false)
 {
     ASSERT(ThisPtr != nullptr);
     //DEV_DEBUG_TRACE("BuildingTypeClassExtension constructor - Name: %s (0x%08X)\n", ThisPtr->Name(), (uintptr_t)(ThisPtr));
@@ -165,6 +165,8 @@ void BuildingTypeClassExtension::Compute_CRC(WWCRCEngine &crc) const
 {
     ASSERT(ThisPtr != nullptr);
     //DEV_DEBUG_TRACE("BuildingTypeClassExtension::Compute_CRC - Name: %s (0x%08X)\n", ThisPtr->Name(), (uintptr_t)(ThisPtr));
+
+    crc(IsEligibleForAllyBuilding);
 }
 
 
@@ -194,6 +196,9 @@ bool BuildingTypeClassExtension::Read_INI(CCINIClass &ini)
     ProduceCashBudget = ini.Get_Int(ini_name, "ProduceCashBudget", ProduceCashBudget);
     IsStartupCashOneTime = ini.Get_Int(ini_name, "ProduceCashStartupOneTime", IsStartupCashOneTime);
     IsResetBudgetOnCapture = ini.Get_Bool(ini_name, "ProduceCashResetOnCapture", IsResetBudgetOnCapture);
+
+    IsEligibleForAllyBuilding = ini.Get_Bool(ini_name, "EligibleForAllyBuilding",
+                                                    ThisPtr->IsConstructionYard ? true : IsEligibleForAllyBuilding);
     
     return true;
 }
diff --git a/src/extensions/buildingtype/buildingtypeext.h b/src/extensions/buildingtype/buildingtypeext.h
index d53bd4921..63e2b38cc 100644
--- a/src/extensions/buildingtype/buildingtypeext.h
+++ b/src/extensions/buildingtype/buildingtypeext.h
@@ -91,6 +91,11 @@ class BuildingTypeClassExtension final : public Extension<BuildingTypeClass>
          *  Reset the available budget when captured?
          */
         bool IsResetBudgetOnCapture;
+
+        /**
+         *  Is this building eligible for proximity checks by players who are its owner's allies?
+         */
+        bool IsEligibleForAllyBuilding;
 };
 
 
diff --git a/src/extensions/display/displayext_hooks.cpp b/src/extensions/display/displayext_hooks.cpp
index 3083e5c20..8a0886c16 100644
--- a/src/extensions/display/displayext_hooks.cpp
+++ b/src/extensions/display/displayext_hooks.cpp
@@ -31,6 +31,14 @@
 #include "tibsun_util.h"
 #include "display.h"
 #include "iomap.h"
+#include "cell.h"
+#include "building.h"
+#include "buildingtype.h"
+#include "buildingtypeext.h"
+#include "house.h"
+#include "housetype.h"
+#include "session.h"
+#include "sessionext.h"
 #include "wwmouse.h"
 #include "fatal.h"
 #include "debughandler.h"
@@ -40,6 +48,68 @@
 #include "hooker_macros.h"
 
 
+/**
+ *  #issue-171
+ * 
+ *  Adds game option to control if allies can build off each others bases.
+ * 
+ *  @author: CCHyper
+ */
+DECLARE_PATCH(_DisplayClass_Passes_Proximity_Passes_Check_Patch)
+{
+    //GET_REGISTER_STATIC(DisplayClass *, this_ptr, ?);   // No access to "this".
+    GET_REGISTER_STATIC(BuildingClass *, base, eax);
+    GET_STACK_STATIC(HousesType, house, esp, 0x38);
+    //GET_STACK_STATIC8(bool, passes, esp, 0x3C);
+    static BuildingTypeClassExtension *buildingtypeext;
+    static HouseClass *hptr;
+
+    /**
+     *  Store the proximity check result.
+     */
+    #define passes() _asm { mov byte ptr [esp+0x3C], 1 }
+
+    hptr = Houses[house];
+
+    /**
+     *  Stolen bytes/code.
+     * 
+     *  Ensure the building is considered eligible for adjacency checks.
+     */
+    if (base->House->ID == house && base->Class->IsBase) {
+        passes();
+    }
+
+    /**
+     *  If the build-off-ally option is enabled, ensure the building is
+     *  owned by an ally house and is eligible for adjacent building before
+     *  passing the check.
+     * 
+     *  #NOTE: This feature is only available for multiplayer games.
+     */
+    if (Session.Type != GAME_NORMAL) {
+        if (SessionExtension && SessionExtension->ExtOptions.IsBuildOffAlly) {
+
+            if (base->House != hptr && base->House->Is_Ally(hptr)) {
+
+                buildingtypeext = BuildingTypeClassExtensions.find(base->Class);
+                if (buildingtypeext && buildingtypeext->IsEligibleForAllyBuilding) {
+#ifndef NDEBUG
+                    //DEV_DEBUG_INFO("Ally \"%s's\" building \"%s\" is eligible for building off.\n", base->House->IniName, base->Name());
+#endif
+                    passes();
+                }
+            }
+        }
+    }
+
+    #undef passes
+
+continue_scan:
+    JMP(0x00476308);
+}
+
+
 /**
  *  #issue-344
  * 
@@ -179,6 +249,7 @@ void DisplayClassExtension_Hooks()
 {
     Patch_Jump(0x0047AFA6, &_DisplayClass_Help_Text_GetCursorPosition_Patch);
     Patch_Jump(0x00478974, &_DisplayClass_Mouse_Left_Release_PlaceAnywhere_BugFix_Patch);
+    Patch_Jump(0x004762E4, &_DisplayClass_Passes_Proximity_Passes_Check_Patch);
 
     /**
      *  #issue-76