1 files changed, 110 insertions, 0 deletions

diff --git a/src/Physics/Tracers/LineBlockTracer.h b/src/Physics/Tracers/LineBlockTracer.h
new file mode 100644
index 000000000..b1dacee20
--- /dev/null
+++ b/src/Physics/Tracers/LineBlockTracer.h
@@ -0,0 +1,110 @@
+
+// LineBlockTracer.h
+
+// Declares the cLineBlockTracer class representing a cBlockTracer that traces along a straight line between two points
+
+
+
+
+
+#pragma once
+
+#include "BlockTracer.h"
+
+
+
+
+
+// fwd: Chunk.h
+class cChunk;
+
+
+
+
+
+class cLineBlockTracer:
+	public cBlockTracer
+{
+	using Super = cBlockTracer;
+
+public:
+
+	enum eLineOfSight
+	{
+		// Bit flags used for LineOfSightTrace's Sight parameter:
+		losAir = 1,    // Can see through air
+		losWater = 2,  // Can see through water
+		losLava = 4,   // Can see through lava
+
+		// Common combinations:
+		losAirWaterLava = losAir | losWater | losLava,
+		losAirWater = losAir | losWater,
+	};
+
+
+	cLineBlockTracer(cWorld & a_World, cCallbacks & a_Callbacks);
+
+	/** Traces one line between Start and End; returns true if the entire line was traced (until OnNoMoreHits()) */
+	bool Trace(Vector3d a_Start, Vector3d a_End);
+
+
+	// Utility functions for simple one-line usage:
+
+	/** Traces one line between Start and End; returns true if the entire line was traced (until OnNoMoreHits()) */
+	static bool Trace(cWorld & a_World, cCallbacks & a_Callbacks, const Vector3d a_Start, const Vector3d a_End);
+
+	/** Returns true if the two positions are within line of sight (not obscured by blocks).
+	a_Sight specifies which blocks are considered transparent for the trace, is an OR-combination of eLineOfSight constants. */
+	static bool LineOfSightTrace(cWorld & a_World, const Vector3d & a_Start, const Vector3d & a_End, int a_Sight);
+
+	/** Traces until the first solid block is hit (or until end, whichever comes first.
+	If a solid block was hit, returns true and fills a_HitCoords, a_HitBlockCoords and a_HitBlockFace.
+	If a_End is encountered without hitting any solid block, returns false and doesn't touch a_HitCoords, a_HitBlockCoords nor a_HitBlockFace.
+	a_HitCoords is the exact coords of the hit,
+	a_HitBlockCoords are the coords of the solid block that was hit,
+	a_HitBlockFace is the face of the solid block that was hit. */
+	static bool FirstSolidHitTrace(
+		cWorld & a_World,
+		const Vector3d & a_Start, const Vector3d & a_End,
+		Vector3d & a_HitCoords,
+		Vector3i & a_HitBlockCoords,
+		eBlockFace & a_HitBlockFace
+	);
+
+protected:
+	/** The start point of the trace */
+	Vector3d m_Start;
+
+	/** The end point of the trace */
+	Vector3d m_End;
+
+	/** The difference in coords, End - Start */
+	Vector3d m_Diff;
+
+	/** The increment at which the block coords are going from Start to End; either +1 or -1 */
+	Vector3i m_Dir;
+
+	/** The current block */
+	Vector3i m_Current;
+
+	/** The face through which the current block has been entered */
+	eBlockFace m_CurrentFace;
+
+
+	/** Adjusts the start point above the world to just at the world's top */
+	void FixStartAboveWorld(void);
+
+	/** Adjusts the start point below the world to just at the world's bottom */
+	void FixStartBelowWorld(void);
+
+	/** Calculates the XZ coords of an intersection with the specified Yconst plane; assumes that such an intersection exists */
+	void CalcXZIntersection(double a_Y, double & a_IntersectX, double & a_IntersectZ);
+
+	/** Moves m_Current to the next block on the line; returns false if no move is possible (reached the end) */
+	bool MoveToNextBlock(void);
+
+	bool ChunkCallback(cChunk * a_Chunk);
+} ;
+
+
+