Move ObjectAtPosition to objects.cpp and make it return a pointer

All set maps initialise objects as expected so dObject has the correct ID already, no need to iterate over all active objects. Also by returning a pointer we can use this function to test if an object exists at the target position.

While on msvc int8_t is typedefed to signed char we might as well match the expected data type for the dObject array

Source/gendung.cpp

@@ -55,7 +55,7 @@ DungeonFlag dFlags[MAXDUNX][MAXDUNY];
 int8_t dPlayer[MAXDUNX][MAXDUNY];
 int16_t dMonster[MAXDUNX][MAXDUNY];
 int8_t dCorpse[MAXDUNX][MAXDUNY];
-char dObject[MAXDUNX][MAXDUNY];
+int8_t dObject[MAXDUNX][MAXDUNY];
 int8_t dItem[MAXDUNX][MAXDUNY];
 char dSpecial[MAXDUNX][MAXDUNY];
 int themeCount;

Source/gendung.h

@@ -223,7 +223,7 @@ extern int16_t dMonster[MAXDUNX][MAXDUNY];
  */
 extern DVL_API_FOR_TEST int8_t dCorpse[MAXDUNX][MAXDUNY];
 /** Contains the object numbers (objects array indices) of the map. */
-extern DVL_API_FOR_TEST char dObject[MAXDUNX][MAXDUNY];
+extern DVL_API_FOR_TEST int8_t dObject[MAXDUNX][MAXDUNY];
 /** Contains the item numbers (items array indices) of the map. */
 extern int8_t dItem[MAXDUNX][MAXDUNY];
 /**

Source/objects.cpp

@@ -682,7 +682,7 @@ void LoadMapObjects(const char *path, Point start, Rectangle mapRange, int lever
 			if (objectId != 0) {
 				Point mapPos = start + Displacement { i, j };
 				AddObject(ObjTypeConv[objectId], mapPos);
-				ObjectAtPosition(mapPos).InitializeLoadedObject(mapRange, leveridx);
+				ObjectAtPosition(mapPos)->InitializeLoadedObject(mapRange, leveridx);
 			}
 		}
 	}
@@ -4350,6 +4350,16 @@ bool Object::IsDisabled() const
 	return IsAnyOf(static_cast<shrine_type>(_oVar1), shrine_type::ShrineFascinating, shrine_type::ShrineOrnate, shrine_type::ShrineSacred);
 }
 
+Object *ObjectAtPosition(Point position)
+{
+	if (InDungeonBounds(position) && dObject[position.x][position.y] != 0) {
+		return &Objects[abs(dObject[position.x][position.y]) - 1];
+	}
+
+	// nothing at this position, return a nullptr
+	return nullptr;
+}
+
 void InitObjectGFX()
 {
 	bool fileload[56] = {};

Source/objects.h

@@ -238,6 +238,14 @@ extern int ActiveObjectCount;
 extern bool ApplyObjectLighting;
 extern bool LoadingMapObjects;
 
+/**
+ * @brief Find an object given a point in map coordinates
+ *
+ * @param position The map coordinate to test
+ * @return A pointer to the object or nullptr if no object exists at this location
+ */
+Object *ObjectAtPosition(Point position);
+
 void InitObjectGFX();
 void FreeObjectGFX();
 void AddL1Objs(int x1, int y1, int x2, int y2);

Source/setmaps.cpp

@@ -87,29 +87,29 @@ BYTE SkelChamTrans3[] = {
 void AddSKingObjs()
 {
 	constexpr Rectangle SmallSecretRoom { { 20, 7 }, { 3, 3 } };
-	ObjectAtPosition({ 64, 34 }).InitializeLoadedObject(SmallSecretRoom, 1);
+	ObjectAtPosition({ 64, 34 })->InitializeLoadedObject(SmallSecretRoom, 1);
 
 	constexpr Rectangle Gate { { 20, 14 }, { 1, 2 } };
-	ObjectAtPosition({ 64, 59 }).InitializeLoadedObject(Gate, 2);
+	ObjectAtPosition({ 64, 59 })->InitializeLoadedObject(Gate, 2);
 
 	constexpr Rectangle LargeSecretRoom { { 8, 1 }, { 7, 10 } };
-	ObjectAtPosition({ 27, 37 }).InitializeLoadedObject(LargeSecretRoom, 3);
-	ObjectAtPosition({ 46, 35 }).InitializeLoadedObject(LargeSecretRoom, 3);
-	ObjectAtPosition({ 49, 53 }).InitializeLoadedObject(LargeSecretRoom, 3);
-	ObjectAtPosition({ 27, 53 }).InitializeLoadedObject(LargeSecretRoom, 3);
+	ObjectAtPosition({ 27, 37 })->InitializeLoadedObject(LargeSecretRoom, 3);
+	ObjectAtPosition({ 46, 35 })->InitializeLoadedObject(LargeSecretRoom, 3);
+	ObjectAtPosition({ 49, 53 })->InitializeLoadedObject(LargeSecretRoom, 3);
+	ObjectAtPosition({ 27, 53 })->InitializeLoadedObject(LargeSecretRoom, 3);
 }
 
 void AddSChamObjs()
 {
-	ObjectAtPosition({ 37, 30 }).InitializeLoadedObject({ { 17, 0 }, { 4, 5 } }, 1);
-	ObjectAtPosition({ 37, 46 }).InitializeLoadedObject({ { 13, 0 }, { 3, 5 } }, 2);
+	ObjectAtPosition({ 37, 30 })->InitializeLoadedObject({ { 17, 0 }, { 4, 5 } }, 1);
+	ObjectAtPosition({ 37, 46 })->InitializeLoadedObject({ { 13, 0 }, { 3, 5 } }, 2);
 }
 
 void AddVileObjs()
 {
-	ObjectAtPosition({ 26, 45 }).InitializeLoadedObject({ { 1, 1 }, { 8, 9 } }, 1);
-	ObjectAtPosition({ 45, 46 }).InitializeLoadedObject({ { 11, 1 }, { 9, 9 } }, 2);
-	ObjectAtPosition({ 35, 36 }).InitializeLoadedObject({ { 7, 11 }, { 6, 7 } }, 3);
+	ObjectAtPosition({ 26, 45 })->InitializeLoadedObject({ { 1, 1 }, { 8, 9 } }, 1);
+	ObjectAtPosition({ 45, 46 })->InitializeLoadedObject({ { 11, 1 }, { 9, 9 } }, 2);
+	ObjectAtPosition({ 35, 36 })->InitializeLoadedObject({ { 7, 11 }, { 6, 7 } }, 3);
 }
 
 void SetmapTransparancy(const char *path)
@@ -137,16 +137,6 @@ void SetmapTransparancy(const char *path)
 
 } // namespace
 
-Object &ObjectAtPosition(Point position)
-{
-	for (int i = 0; i < ActiveObjectCount; i++) {
-		int oi = ActiveObjects[i];
-		if (Objects[oi].position == position)
-			return Objects[oi];
-	}
-	app_fatal("ObjectAtPosition: Active object not found at (%i,%i)", position.x, position.y);
-}
-
 void LoadSetMap()
 {
 	switch (setlvlnum) {

Source/setmaps.h

@@ -11,14 +11,6 @@
 
 namespace devilution {
 
-/**
- * @brief Find an object given a point in map coordinates
- *
- * @param position The map coordinate to test
- * @return A reference to the object
- */
-Object &ObjectAtPosition(Point position);
-
 /**
  * @brief Load a quest map, the given map is specified via the global setlvlnum
  */