1 files changed, 96 insertions, 0 deletions

diff --git a/src/Mobs/PathFinder.h b/src/Mobs/PathFinder.h
new file mode 100644
index 000000000..1570679bf
--- /dev/null
+++ b/src/Mobs/PathFinder.h
@@ -0,0 +1,96 @@
+
+#pragma once
+#include "Path.h"
+
+#define WAYPOINT_RADIUS 0.5
+/*
+TODO DOXY style
+
+This class wraps cPath.
+cPath is a "dumb device" - You give it point A and point B, and it returns a full path path.
+cPathFinder - You give it a constant stream of point A (where you are) and point B (where you want to go),
+and it tells you where to go next. It manages path recalculation internally, and is much more efficient that calling cPath every step.
+
+*/
+
+class cPathFinder
+{
+
+public:
+	/** Creates a cPathFinder instance. Each mob should have one cPathFinder throughout its lifetime.
+	@param a_MobWidth The mob width.
+	@param a_MobWidth The mob height.
+	*/
+	cPathFinder(double a_MobWidth, double a_MobHeight);
+
+	/** Updates the PathFinder's internal state and returns a waypoint.
+	A waypoint is a coordinate which the mob can safely move to from its current position in a straight line.
+	The mob is expected to call this function tick as long as it is following a path.
+	@param a_Chunk The chunk in which the mob is currently at.
+	@param a_Source The mob's position. a_Source's coordinates are expected to be within the chunk given in a_Chunk.
+	@param a_Destination The position the mob would like to reach. If a_ExactPath is true, the PathFinder may modify this.
+	@param a_OutputWaypoint An output parameter: The next waypoint to go to.
+	@param a_DontCare If true, the mob doesn't care where to go, and the Pathfinder may modify a_Destination.
+	This should usually be false. An exception is a wandering idle mob which doesn't care about its final destination.
+	In the future, idle mobs shouldn't use A* at all.
+
+	Returns an ePathFinderStatus.
+	ePathFinderStatus:CALCULATING - The PathFinder is still processing a path. Nothing was written to a_OutputWaypoint. The mob should probably not move.
+	ePathFinderStatus:PATH_FOUND - The PathFinder has found a path to the target. The next waypoint was written a_OutputWaypoint. The mob should probably move to a_OutputWaypoint.
+	ePathFinderStatus:NEARBY_FOUND - The PathFinder did not find a destination to the target but did find a nearby spot. The next waypoint was written a_OutputWaypoint. The mob should probably move to a_OutputWaypoint.
+	ePathFinderStatus:PATH_NOT_FOUND - The PathFinder did not find a destination to the target. Nothing was written to a_OutputWaypoint. The mob should probably not move.
+
+	Note: Once NEARBY_FOUND is returned once, subsequent calls return PATH_FOUND. */
+	ePathFinderStatus GetNextWayPoint(cChunk & a_Chunk, const Vector3d & a_Source, Vector3d * a_Destination, Vector3d * a_OutputWaypoint, bool a_DontCare = false);
+
+private:
+
+	/** The width of the Mob which owns this PathFinder. */
+	double m_Width;
+
+	/** The height of the Mob which owns this PathFinder. */
+	double m_Height;
+
+	/** The current cPath instance we have. This is discarded and recreated when a path recalculation is needed. */
+	cPath m_Path;
+
+	/** If 0, will give up reaching the next m_WayPoint and will recalculate path. */
+	int m_GiveUpCounter;
+
+	/** Coordinates of the next position that should be reached. */
+	Vector3d m_WayPoint;
+
+	/** Coordinates for where we should go. This is out ultimate, final destination. */
+	Vector3d m_FinalDestination;
+
+	/** Coordinates for where we are practically going. */
+	Vector3d m_PathDestination;
+
+	/** When FinalDestination is too far from this, we recalculate.
+	This usually equals PathDestination. Except when m_NoPathToTarget is true. */
+	Vector3d m_DeviationOrigin;
+
+
+	/** Coordinates for where the mob is currently at. */
+	Vector3d m_Source;
+
+	/** True if there's no path to target and we're walking to a nearby location instead. */
+	bool m_NoPathToTarget;
+
+	/** When a path is not found, this cooldown prevents any recalculations for several ticks. */
+	int m_NotFoundCooldown;
+
+	/** Ensures the destination is not buried underground or under water. Also ensures the destination is not in the air.
+	Only the Y coordinate of m_FinalDestination might be changed by this call.
+	1. If m_FinalDestination is the position of a water block, m_FinalDestination's Y will be modified to point to the heighest water block in the pool in the current column.
+	2. If m_FinalDestination is the position of a solid, m_FinalDestination's Y will be modified to point to the first airblock above the solid in the current column.
+	3. If m_FinalDestination is the position of an air block, Y will keep decreasing until hitting either a solid or water.
+	Now either 1 or 2 is performed. */
+	bool EnsureProperDestination(cChunk & a_Chunk);
+
+	/** Resets a pathfinding task, typically because m_FinalDestination has deviated too much from m_DeviationOrigin. */
+	void ResetPathFinding(cChunk &a_Chunk);
+
+	/** Is the path too old and should be recalculated? When this is true ResetPathFinding() is called. */
+	bool PathIsTooOld() const;
+};