3 files changed, 38 insertions, 45 deletions

diff --git a/source/Bindings.cpp b/source/Bindings.cpp
index a052d1062..4bcfe8cbb 100644
--- a/source/Bindings.cpp
+++ b/source/Bindings.cpp
@@ -23790,41 +23790,6 @@ static int tolua_AllToLua_cTracer_Trace00(lua_State* tolua_S)
 }
 #endif //#ifndef TOLUA_DISABLE
 
-/* method: SetValues of class  cTracer */
-#ifndef TOLUA_DISABLE_tolua_AllToLua_cTracer_SetValues00
-static int tolua_AllToLua_cTracer_SetValues00(lua_State* tolua_S)
-{
-#ifndef TOLUA_RELEASE
- tolua_Error tolua_err;
- if (
-     !tolua_isusertype(tolua_S,1,"cTracer",0,&tolua_err) ||
-     (tolua_isvaluenil(tolua_S,2,&tolua_err) || !tolua_isusertype(tolua_S,2,"const Vector3f",0,&tolua_err)) ||
-     (tolua_isvaluenil(tolua_S,3,&tolua_err) || !tolua_isusertype(tolua_S,3,"const Vector3f",0,&tolua_err)) ||
-     !tolua_isnoobj(tolua_S,4,&tolua_err)
- )
-  goto tolua_lerror;
- else
-#endif
- {
-  cTracer* self = (cTracer*)  tolua_tousertype(tolua_S,1,0);
-  const Vector3f* a_Start = ((const Vector3f*)  tolua_tousertype(tolua_S,2,0));
-  const Vector3f* a_Direction = ((const Vector3f*)  tolua_tousertype(tolua_S,3,0));
-#ifndef TOLUA_RELEASE
-  if (!self) tolua_error(tolua_S,"invalid 'self' in function 'SetValues'", NULL);
-#endif
-  {
-   self->SetValues(*a_Start,*a_Direction);
-  }
- }
- return 0;
-#ifndef TOLUA_RELEASE
- tolua_lerror:
- tolua_error(tolua_S,"#ferror in function 'SetValues'.",&tolua_err);
- return 0;
-#endif
-}
-#endif //#ifndef TOLUA_DISABLE
-
 /* get function: BlockHitPosition of class  cTracer */
 #ifndef TOLUA_DISABLE_tolua_get_cTracer_BlockHitPosition
 static int tolua_get_cTracer_BlockHitPosition(lua_State* tolua_S)
@@ -30959,7 +30924,6 @@ TOLUA_API int tolua_AllToLua_open (lua_State* tolua_S)
    tolua_function(tolua_S,".call",tolua_AllToLua_cTracer_new00_local);
    tolua_function(tolua_S,"delete",tolua_AllToLua_cTracer_delete00);
    tolua_function(tolua_S,"Trace",tolua_AllToLua_cTracer_Trace00);
-   tolua_function(tolua_S,"SetValues",tolua_AllToLua_cTracer_SetValues00);
    tolua_variable(tolua_S,"BlockHitPosition",tolua_get_cTracer_BlockHitPosition,tolua_set_cTracer_BlockHitPosition);
    tolua_variable(tolua_S,"HitNormal",tolua_get_cTracer_HitNormal,tolua_set_cTracer_HitNormal);
    tolua_variable(tolua_S,"RealHit",tolua_get_cTracer_RealHit,tolua_set_cTracer_RealHit);
diff --git a/source/Tracer.cpp b/source/Tracer.cpp
index 42f1ae5dd..ef136302f 100644
--- a/source/Tracer.cpp
+++ b/source/Tracer.cpp
@@ -131,12 +131,12 @@ void cTracer::SetValues(const Vector3f & a_Start, const Vector3f & a_Direction)
 
 
 
-int cTracer::Trace( const Vector3f & a_Start, const Vector3f & a_Direction, int a_Distance)
+bool cTracer::Trace( const Vector3f & a_Start, const Vector3f & a_Direction, int a_Distance, bool a_LineOfSight)
 {
 	if ((a_Start.y < 0) || (a_Start.y >= cChunkDef::Height))
 	{
 		LOGD("%s: Start Y is outside the world (%.2f), not tracing.", __FUNCTION__, a_Start.y);
-		return 0;
+		return false;
 	}
 	
 	SetValues(a_Start, a_Direction);
@@ -157,7 +157,7 @@ int cTracer::Trace( const Vector3f & a_Start, const Vector3f & a_Direction, int
 	// check if first is occupied
 	if (pos.Equals(end1))
 	{
-		return 0;
+		return false;
 	}
 
 	bool reachedX = false, reachedY = false, reachedZ = false;
@@ -224,8 +224,9 @@ int cTracer::Trace( const Vector3f & a_Start, const Vector3f & a_Direction, int
 		}
 		
 		BLOCKTYPE BlockID = m_World->GetBlock(pos.x, pos.y, pos.z);
-		// No collision with water ;)
-		if ((BlockID != E_BLOCK_AIR) || IsBlockWater(BlockID))  // _X 2013_03_29: Why is the IsBlockWater condition here? water equals air?
+		// Block is counted as a collision if we are not doing a line of sight and it is solid,
+		// or if the block is not air and not water. That way mobs can still see underwater.
+		if ((!a_LineOfSight && g_BlockIsSolid[BlockID]) || (a_LineOfSight && (BlockID != E_BLOCK_AIR) && !IsBlockWater(BlockID)))
 		{
 			BlockHitPosition = pos;
 			int Normal = GetHitNormal(a_Start, End, pos );
@@ -233,10 +234,10 @@ int cTracer::Trace( const Vector3f & a_Start, const Vector3f & a_Direction, int
 			{
 				HitNormal = m_NormalTable[Normal-1];
 			}
-			return 1;
+			return true;
 		}
 	}
-	return 0;
+	return false;
 }
 
 
diff --git a/source/Tracer.h b/source/Tracer.h
index 2f627366f..bc348d955 100644
--- a/source/Tracer.h
+++ b/source/Tracer.h
@@ -12,14 +12,42 @@ public:				// tolua_export
 	Vector3f BoxOffset;
 	cTracer( cWorld* a_World);		// tolua_export
 	~cTracer();						// tolua_export
-	int Trace( const Vector3f & a_Start, const Vector3f & a_Direction, int a_Distance );		// tolua_export
-	void SetValues( const Vector3f & a_Start, const Vector3f & a_Direction );					// tolua_export
+
+	/// Determines if a collision occures along a line. Returns true if a collision occurs.
+	bool Trace( const Vector3f & a_Start, const Vector3f & a_Direction, int a_Distance)	// tolua_export
+	{
+		return Trace(a_Start, a_Direction, a_Distance, false);
+	}
+
+	/// Determines if a collision occures along a line. Returns true if a collision occurs.
+	/// When a_LineOfSight is true, we don't use the standard collision detection rules. Instead we use
+	/// the rules for monster vision. E.g. Only water and air do not block vision.
+	bool Trace( const Vector3f & a_Start, const Vector3f & a_Direction, int a_Distance, bool a_LineOfSight);		// tolua_export
+
+	/// Contains the position of the block that caused the collision
 	Vector3f BlockHitPosition;		// tolua_export
+
+	/// Contains which face was hit
 	Vector3f HitNormal;			// tolua_export
+
+	/// Contains the exact position where a collision occured. (BlockHitPosition + Offset on block)
 	Vector3f RealHit;				// tolua_export
 private:
+
+	/// Preps Tracer object for call of Trace function. Only used internally.
+	void SetValues( const Vector3f & a_Start, const Vector3f & a_Direction );
+
+	/// Calculates where on the block a collision occured, if it does occur
+	/// Returns 0 if no intersection occured
+	/// Returns 1 if an intersection occured at a single point
+	/// Returns 2 if the line segment lies in the plane being checked 
 	int intersect3D_SegmentPlane( const Vector3f & a_Origin, const Vector3f & a_End, const Vector3f & a_PlanePos, const Vector3f & a_PlaneNormal );
+	
+	/// Determines which face on the block a collision occured, if it does occur
+	/// Returns 0 if the block is air, water or no collision occured
+	/// Return 1 through 6 for the following block faces, repectively: -x, -z, x, z, y, -y
 	int GetHitNormal( const Vector3f & start, const Vector3f & end, const Vector3i &  a_BlockPos);
+
 	float SigNum( float a_Num );
 	cWorld* m_World;