From 8e9e536353106191f66379857f64f625791bb003 Mon Sep 17 00:00:00 2001
From: CCHyper <73803386+CCHyper@users.noreply.github.com>
Date: Wed, 20 Oct 2021 00:28:50 +0100
Subject: [PATCH] Implements IsCanRecalcApproachTarget for TechnoTypes.

---
 src/extensions/foot/footext_hooks.cpp       | 64 +++++++++++++++++++++
 src/extensions/technotype/technotypeext.cpp |  2 +
 src/extensions/technotype/technotypeext.h   |  6 ++
 3 files changed, 72 insertions(+)

diff --git a/src/extensions/foot/footext_hooks.cpp b/src/extensions/foot/footext_hooks.cpp
index 2867be894..c67493360 100644
--- a/src/extensions/foot/footext_hooks.cpp
+++ b/src/extensions/foot/footext_hooks.cpp
@@ -29,7 +29,11 @@
 #include "foot.h"
 #include "technotype.h"
 #include "technotypeext.h"
+#include "tibsun_inline.h"
 #include "house.h"
+#include "rules.h"
+#include "rulesext.h"
+#include "target.h"
 #include "fatal.h"
 #include "asserthandler.h"
 #include "debughandler.h"
@@ -38,6 +42,65 @@
 #include "hooker_macros.h"
 
 
+/**
+ *  #issue-595
+ * 
+ *  Implements IsCanRecalcApproachTarget for TechnoTypes.
+ * 
+ *  @author: CCHyper
+ */
+static short NavCom_TarCom_Distance(FootClass *this_ptr) { return Distance(this_ptr->NavCom->Center_Coord(), this_ptr->TarCom->Center_Coord()); }
+static int Multiply_Integer(int a, double b) { return (a * b); }
+DECLARE_PATCH(_FootClass_Approach_Target_Can_Recalc_Approach_Target_Patch)
+{
+    GET_REGISTER_STATIC(FootClass *, this_ptr, ebp);
+    GET_REGISTER_STATIC(bool, in_range, bl);
+    GET_STACK_STATIC(int, maxrange, esp, 0x34);
+    static TechnoTypeClassExtension *technotypeext;
+
+    if (Target_Legal(this_ptr->NavCom)) {
+
+        if (Target_Legal(this_ptr->TarCom)) {
+
+            technotypeext = TechnoTypeClassExtensions.find(this_ptr->Techno_Type_Class());
+            if (technotypeext && technotypeext->IsCanRecalcApproachTarget) {
+
+                //DEV_DEBUG_INFO("Approach_Target: CanRecalcApproachTarget branch.\n");
+
+                if (!in_range) {
+
+                    static double reset_multiplier = 1.0;
+                    if (RulesExtension) {
+                        reset_multiplier = RulesExtension->ApproachTargetResetMultiplier;
+                    }
+
+                    if (NavCom_TarCom_Distance(this_ptr) > Multiply_Integer(maxrange, reset_multiplier)) {
+                        DEV_DEBUG_INFO("Approach_Target: Clearing NavCom.\n");
+                        this_ptr->NavCom = nullptr;
+                    }
+
+                }
+
+            }
+
+        }
+
+        if (Target_Legal(this_ptr->NavCom)) {
+            if (!this_ptr->In_Air()) {
+                goto function_return;
+            }
+        }
+    }
+
+    _asm { mov bl, byte ptr [in_range] }    // restore BL register.
+
+    JMP(0x004A2004);
+
+function_return:
+    JMP(0x004A2813);
+}
+
+
 /**
  *  #issue-595
  * 
@@ -231,4 +294,5 @@ void FootClassExtension_Hooks()
     Patch_Jump(0x004A6866, &_FootClass_Is_Allowed_To_Recloak_Cloak_Stop_BugFix_Patch);
     Patch_Jump(0x004A59E1, &_FootClass_AI_IdleRate_Patch);
     Patch_Jump(0x004A1EA8, &_FootClass_Approach_Target_Can_Approach_Patch);
+    Patch_Jump(0x004A1FEA, &_FootClass_Approach_Target_Can_Recalc_Approach_Target_Patch);
 }
diff --git a/src/extensions/technotype/technotypeext.cpp b/src/extensions/technotype/technotypeext.cpp
index e8eb6e2e7..c4d9ac46e 100644
--- a/src/extensions/technotype/technotypeext.cpp
+++ b/src/extensions/technotype/technotypeext.cpp
@@ -52,6 +52,7 @@ TechnoTypeClassExtension::TechnoTypeClassExtension(TechnoTypeClass *this_ptr) :
     IsShakeScreen(false),
     IsImmuneToEMP(false),
     IsCanApproachTarget(true),
+    IsCanRecalcApproachTarget(true),
     ShakePixelYHi(0),
     ShakePixelYLo(0),
     ShakePixelXHi(0),
@@ -237,6 +238,7 @@ bool TechnoTypeClassExtension::Read_INI(CCINIClass &ini)
     VoiceDeploy = ini.Get_VocType_List(ini_name, "VoiceDeploy", VoiceDeploy);
     VoiceHarvest = ini.Get_VocType_List(ini_name, "VoiceHarvest", VoiceHarvest);
     IsCanApproachTarget = ini.Get_Bool(ini_name, "CanApproachTarget", IsCanApproachTarget);
+    IsCanRecalcApproachTarget = ini.Get_Bool(ini_name, "CanRecalcApproachTarget", IsCanRecalcApproachTarget);
 
     IdleRate = ini.Get_Int(ini_name, "IdleRate", IdleRate);
     IdleRate = ArtINI.Get_Int(graphic_name, "IdleRate", IdleRate);
diff --git a/src/extensions/technotype/technotypeext.h b/src/extensions/technotype/technotypeext.h
index ab19deb6a..b579bf2e0 100644
--- a/src/extensions/technotype/technotypeext.h
+++ b/src/extensions/technotype/technotypeext.h
@@ -83,6 +83,12 @@ class TechnoTypeClassExtension final : public Extension<TechnoTypeClass>
          */
         bool IsCanApproachTarget;
 
+        /**
+         *  Can this unit recalculate what its next target will be when conducting
+         *  its threat scan if its current target is out of range?
+         */
+        bool IsCanRecalcApproachTarget;
+
         /**
          *  These values are used to shake the screen when the object is destroyed.
          */