Adds the "Underground" layer to the tactical display Next and Prev search.

src/extensions/display/displayext_hooks.cpp

@@ -37,6 +37,7 @@
 #include "buildingtypeext.h"
 #include "house.h"
 #include "housetype.h"
+#include "layer.h"
 #include "session.h"
 #include "sessionext.h"
 #include "wwmouse.h"
@@ -49,6 +50,116 @@
 #include "hooker_macros.h"
 
 
+/**
+ *  A fake class for implementing new member functions which allow
+ *  access to the "this" pointer of the intended class.
+ * 
+ *  @note: This must not contain a constructor or destructor!
+ *  @note: All functions must be prefixed with "_" to prevent accidental virtualization.
+ */
+class DisplayClassExt final : public DisplayClass
+{
+    public:
+        ObjectClass * _Next_Object(ObjectClass * object) const;
+        ObjectClass * _Prev_Object(ObjectClass * object) const;
+};
+
+
+/**
+ *  Reimplementation of DisplayClass::Next_Object.
+ * 
+ *  Searches for next object on display.
+ * 
+ *  @author: 06/20/1994 JLB - Red Alert source code.
+ *           CCHyper - Adjustments for Tiberian Sun.
+ */
+ObjectClass * DisplayClassExt::_Next_Object(ObjectClass * object) const
+{
+    static const LayerType _layers[] = {
+
+        /**
+         *  #issue-785
+         * 
+         *  Adds underground layer to display search.
+         */
+        LAYER_UNDERGROUND,
+
+        LAYER_GROUND, LAYER_AIR, LAYER_TOP,
+    };
+
+    ObjectClass * firstobj = nullptr;
+    bool foundmatch = false;
+
+    if (object == nullptr) {
+        foundmatch = true;
+    }
+    for (int index = 0; index < ARRAY_SIZE(_layers); ++index) {
+        LayerType layer = _layers[index];
+
+        for (unsigned uindex = 0; uindex < (unsigned)Layer[layer].Count(); uindex++) {
+            ObjectClass * obj = Layer[layer][uindex];
+
+            /**
+             *  Verify that the object can be selected by and is owned by the player.
+             */
+            if (obj != nullptr && obj->Is_Players_Army()) {
+                if (firstobj == nullptr) firstobj = obj;
+                if (foundmatch) return obj;
+                if (object == obj) foundmatch = true;
+            }
+        }
+    }
+    return firstobj;
+}
+
+
+/**
+ *  Reimplementation of DisplayClass::Next_Object.
+ * 
+ *  Searches for the previous object on the map.
+ * 
+ *  @author: 08/24/1995 JLB - Red Alert source code.
+ *           CCHyper - Adjustments for Tiberian Sun.
+ */
+ObjectClass * DisplayClassExt::_Prev_Object(ObjectClass * object)  const
+{
+    static const LayerType _layers[] = {
+        LAYER_TOP, LAYER_AIR, LAYER_GROUND,
+
+        /**
+         *  #issue-785
+         * 
+         *  Adds underground layer to display search.
+         */
+        LAYER_UNDERGROUND,
+    };
+
+    ObjectClass * firstobj = nullptr;
+    bool foundmatch = false;
+
+    if (object == nullptr) {
+        foundmatch = true;
+    }
+    for (int index = 0; index < ARRAY_SIZE(_layers); ++index) {
+        LayerType layer = _layers[index];
+
+        for (int uindex = Layer[layer].Count()-1; uindex >= 0; uindex--) {
+            ObjectClass * obj = Layer[layer][uindex];
+
+            /**
+             *  Verify that the object can be selected by and is owned by the player.
+             */
+            if (obj != nullptr && obj->Is_Players_Army()) {
+                if (firstobj == nullptr) firstobj = obj;
+                if (foundmatch) return obj;
+                if (object == obj) foundmatch = true;
+            }
+        }
+    }
+    return firstobj;
+}
+
+
 /**
  *  #issue-171
  * 
@@ -270,4 +381,7 @@ void DisplayClassExtension_Hooks()
     Patch_Dword(0x0047A0B5+1, ISOMAPPACK_BUFF_WIDTH);
     Patch_Dword(0x0047A0BA+1, ISOMAPPACK_BUFF_HEIGHT);
     Patch_Dword(0x0047A0C8+1, ISOMAPPACK_BUFF_WIDTH*ISOMAPPACK_BUFF_HEIGHT*sizeof(unsigned short));
+
+    Patch_Jump(0x00477390, &DisplayClassExt::_Next_Object);
+    Patch_Jump(0x00477430, &DisplayClassExt::_Prev_Object);
 }