Fixes for handling of oversized map dwellings

- Marked large version of H3 Unicorn's Glade as not usable for random
dwelling replacement
- Shifted oversized dwellings - that have at most 2x2 as blocked tile,
but have non-blocked tile column will now be placed correctly
- This fixes incorrect random dwelling replacement of the only oversized
H3 dwelling - Portal of Glory
- Game will now detect & report invalid dwelling templates from mods
- Updated docs to clarify dwellings format

lib/mapObjectConstructors/AObjectTypeHandler.cpp

@@ -175,6 +175,7 @@ void AObjectTypeHandler::clearTemplates()
 void AObjectTypeHandler::addTemplate(const std::shared_ptr<const ObjectTemplate> & templ)
 {
 	templates.push_back(templ);
+	onTemplateAdded(templ);
 }
 
 void AObjectTypeHandler::addTemplate(JsonNode config)

lib/mapObjectConstructors/AObjectTypeHandler.h

@@ -57,6 +57,8 @@ protected:
 
 	/// initialization for classes that inherit this one
 	virtual void initTypeData(const JsonNode & input);
+
+	virtual void onTemplateAdded(const std::shared_ptr<const ObjectTemplate>) {}
 public:
 
 	AObjectTypeHandler();

lib/mapObjectConstructors/DwellingInstanceConstructor.cpp

@@ -15,7 +15,9 @@
 #include "../json/JsonRandom.h"
 #include "../GameLibrary.h"
 #include "../mapObjects/CGDwelling.h"
+#include "../mapObjects/ObjectTemplate.h"
 #include "../modding/IdentifierStorage.h"
+#include "../CConfigHandler.h"
 
 VCMI_LIB_NAMESPACE_BEGIN
 
@@ -52,6 +54,30 @@ void DwellingInstanceConstructor::initTypeData(const JsonNode & input)
 	}
 	guards = input["guards"];
 	bannedForRandomDwelling = input["bannedForRandomDwelling"].Bool();
+
+	for (const auto & mapTemplate : getTemplates())
+		onTemplateAdded(mapTemplate);
+}
+
+void DwellingInstanceConstructor::onTemplateAdded(const std::shared_ptr<const ObjectTemplate> mapTemplate)
+{
+	if (bannedForRandomDwelling || settings["mods"]["validation"].String() == "off")
+		return;
+
+	bool invalidForRandomDwelling = false;
+	int3 corner = mapTemplate->getCornerOffset();
+
+	for (const auto & tile : mapTemplate->getBlockedOffsets())
+		invalidForRandomDwelling |= (tile.x != -corner.x && tile.x != -corner.x-1) || (tile.y != -corner.y && tile.y != -corner.y-1);
+
+	for (const auto & tile : {mapTemplate->getVisitableOffset()})
+		invalidForRandomDwelling |= (tile.x != corner.x && tile.x != corner.x+1) || tile.y != corner.y;
+
+	invalidForRandomDwelling |= !mapTemplate->isBlockedAt(corner.x+0, corner.y) && !mapTemplate->isVisibleAt(corner.x+0, corner.y);
+	invalidForRandomDwelling |= !mapTemplate->isBlockedAt(corner.x+1, corner.y) && !mapTemplate->isVisibleAt(corner.x+1, corner.y);
+
+	if (invalidForRandomDwelling)
+		logMod->warn("Dwelling %s has template %s which is not valid for a random dwelling! Dwellings must not block tiles outside 2x2 range and must be visitable in bottom row. Change dwelling mask or mark dwelling as 'bannedForRandomDwelling'", getJsonKey(), mapTemplate->animationFile.getOriginalName());
 }
 
 bool DwellingInstanceConstructor::isBannedForRandomDwelling() const
@@ -152,5 +178,4 @@ std::vector<const CCreature *> DwellingInstanceConstructor::getProducedCreatures
 	return creatures;
 }
 
-
 VCMI_LIB_NAMESPACE_END

lib/mapObjectConstructors/DwellingInstanceConstructor.h

@@ -28,6 +28,7 @@ class DwellingInstanceConstructor : public CDefaultObjectTypeHandler<CGDwelling>
 protected:
 	bool objectFilter(const CGObjectInstance * obj, std::shared_ptr<const ObjectTemplate> tmpl) const override;
 	void initTypeData(const JsonNode & input) override;
+	void onTemplateAdded(const std::shared_ptr<const ObjectTemplate>) override;
 
 public:
 	bool hasNameTextID() const override;