Support revealing a small area of the map

source/simulation2/components/CCmpRangeManager.cpp

@@ -2130,6 +2130,88 @@ public:
 			SeeExploredEntities(p);
 	}
 
+	// Convert world-space circle to tile-space bounds
+	struct TileCircle
+	{
+		i32 centerX, centerZ;
+		i32 radius;
+		i32 squaredRadius;
+		i32 minX, maxX, minZ, maxZ;
+	};
+
+	TileCircle WorldToTileCircle(entity_pos_t worldX, entity_pos_t worldZ, entity_pos_t radius)
+	{
+		const i32 centerTileX = (worldX / LOS_TILE_SIZE).ToInt_RoundToNearest();
+		const i32 centerTileZ = (worldZ / LOS_TILE_SIZE).ToInt_RoundToNearest();
+		const i32 tileRadius = (radius / LOS_TILE_SIZE).ToInt_RoundToInfinity();
+
+		return {
+			centerTileX,
+			centerTileZ,
+			tileRadius,
+			tileRadius * tileRadius,
+			std::max(centerTileX - tileRadius, 0),
+			std::min(centerTileX + tileRadius, m_LosVerticesPerSide - 1),
+			std::max(centerTileZ - tileRadius, 0),
+			std::min(centerTileZ + tileRadius, m_LosVerticesPerSide - 1)
+		};
+	}
+
+	// Apply an action to every tile within the circle
+	template<typename Func>
+	void ForEachTileInCircle(const TileCircle& circle, Func&& func)
+	{
+		for (i32 tileZ = circle.minZ; tileZ <= circle.maxZ; ++tileZ)
+		{
+			const i32 deltaZ = tileZ - circle.centerZ;
+			const i32 squaredDeltaZ = deltaZ * deltaZ;
+
+			for (i32 tileX = circle.minX; tileX <= circle.maxX; ++tileX)
+			{
+				if (LosIsOffWorld(tileX, tileZ))
+					continue;
+
+				const i32 deltaX = tileX - circle.centerX;
+				if (deltaX * deltaX + squaredDeltaZ > circle.squaredRadius)
+					continue;
+
+				func(tileX, tileZ);
+			}
+		}
+	}
+
+	void ExploreCircle(player_id_t playerId, entity_pos_t worldX, entity_pos_t worldZ, entity_pos_t radius) override
+	{
+		if (playerId <= 0 || playerId > MAX_LOS_PLAYER_ID)
+			return;
+
+		const TileCircle circle = WorldToTileCircle(worldX, worldZ, radius);
+		const u32 exploredBitMask = static_cast<u32>(LosState::EXPLORED) << (2 * (playerId - 1));
+		u32& exploredCount = m_ExploredVertices.at(playerId);
+		bool hasChanges = false;
+
+		// Mark newly explored tiles and count them
+		ForEachTileInCircle(circle, [&](i32 tileX, i32 tileZ)
+		{
+			u32& losState = m_LosState.get(tileX, tileZ);
+			if (!(losState & exploredBitMask))
+			{
+				losState |= exploredBitMask;
+				++exploredCount;
+				hasChanges = true;
+			}
+		});
+
+		if (!hasChanges)
+			return;
+
+		// Mark visibility dirty for affected regions
+		ForEachTileInCircle(circle, [&](i32 tileX, i32 tileZ)
+		{
+			MarkVisibilityDirtyAroundTile(playerId, tileX, tileZ);
+		});
+	}
+
 	/**
 	 * Force any entity in explored territory to appear for player p.
 	 * This is useful for miraging entities inside the territory borders at the beginning of a game,

source/simulation2/components/ICmpRangeManager.cpp

@@ -62,6 +62,7 @@ DEFINE_INTERFACE_METHOD("GetGaiaAndNonGaiaEntities", ICmpRangeManager, GetGaiaAn
 DEFINE_INTERFACE_METHOD("SetDebugOverlay", ICmpRangeManager, SetDebugOverlay)
 DEFINE_INTERFACE_METHOD("ExploreMap", ICmpRangeManager, ExploreMap)
 DEFINE_INTERFACE_METHOD("ExploreTerritories", ICmpRangeManager, ExploreTerritories)
+DEFINE_INTERFACE_METHOD("ExploreCircle", ICmpRangeManager, ExploreCircle)
 DEFINE_INTERFACE_METHOD("SetLosRevealWholeMap", ICmpRangeManager, SetLosRevealWholeMap)
 DEFINE_INTERFACE_METHOD("GetLosRevealWholeMap", ICmpRangeManager, GetLosRevealWholeMap)
 DEFINE_INTERFACE_METHOD("SetLosRevealWholeMapForAll", ICmpRangeManager, SetLosRevealWholeMapForAll)

source/simulation2/components/ICmpRangeManager.h

@@ -333,6 +333,12 @@ public:
 	 */
 	virtual void ExploreTerritories() = 0;
 
+	/**
+	 * Explore a circular area of the map for the given player.
+	 * This marks the tiles as explored (fogged) but not necessarily visible.
+	 */
+	virtual void ExploreCircle(player_id_t p, entity_pos_t x, entity_pos_t z, entity_pos_t radius) = 0;
+
 	/**
 	 * Reveal the shore for specified player p.
 	 * This works like for entities: if RevealShore is called multiple times with enabled, it