+/*!
+ * Corrects the light in a map block.
+ * For server use only.
+ *
+ * \param block the block to update
+ */
+void repair_block_light(ServerMap *map, MapBlock *block,
+ std::map<v3s16, MapBlock*> *modified_blocks);
+
+/*!
+ * This class iterates trough voxels that intersect with
+ * a line. The collision detection does not see nodeboxes,
+ * every voxel is a cube and is returned.
+ * This iterator steps to all nodes exactly once.
+ */
+struct VoxelLineIterator
+{
+public:
+ //! Starting position of the line in world coordinates.
+ v3f m_start_position;
+ //! Direction and length of the line in world coordinates.
+ v3f m_line_vector;
+ /*!
+ * Each component stores the next smallest positive number, by
+ * which multiplying the line's vector gives a vector that ends
+ * on the intersection of two nodes.
+ */
+ v3f m_next_intersection_multi { 10000.0f, 10000.0f, 10000.0f };
+ /*!
+ * Each component stores the smallest positive number, by which
+ * m_next_intersection_multi's components can be increased.
+ */
+ v3f m_intersection_multi_inc { 10000.0f, 10000.0f, 10000.0f };
+ /*!
+ * Direction of the line. Each component can be -1 or 1 (if a
+ * component of the line's vector is 0, then there will be 1).
+ */
+ v3s16 m_step_directions { 1, 1, 1 };
+ //! Position of the current node.
+ v3s16 m_current_node_pos;
+ //! Index of the current node
+ s16 m_current_index = 0;
+ //! Position of the start node.
+ v3s16 m_start_node_pos;
+ //! Index of the last node
+ s16 m_last_index;
+
+ /*!
+ * Creates a voxel line iterator with the given line.
+ * @param start_position starting point of the line
+ * in voxel coordinates
+ * @param line_vector length and direction of the
+ * line in voxel coordinates. start_position+line_vector
+ * is the end of the line
+ */
+ VoxelLineIterator(const v3f &start_position,const v3f &line_vector);
+
+ /*!
+ * Steps to the next voxel.
+ * Updates m_current_node_pos and
+ * m_previous_node_pos.
+ * Note that it works even if hasNext() is false,
+ * continuing the line as a ray.
+ */
+ void next();
+
+ /*!
+ * Returns true if the next voxel intersects the given line.
+ */
+ inline bool hasNext() const
+ {
+ return m_current_index < m_last_index;
+ }
+
+ /*!
+ * Returns how many times next() must be called until
+ * voxel==m_current_node_pos.
+ * If voxel does not intersect with the line,
+ * the result is undefined.
+ */
+ s16 getIndex(v3s16 voxel);
+};
+
+} // namespace voxalgo