1 /*
2 Minetest
3 Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
4 
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as published by
7 the Free Software Foundation; either version 2.1 of the License, or
8 (at your option) any later version.
9 
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 GNU Lesser General Public License for more details.
14 
15 You should have received a copy of the GNU Lesser General Public License along
16 with this program; if not, write to the Free Software Foundation, Inc.,
17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 */
19 
20 #pragma once
21 
22 #include "voxel.h"
23 #include "mapnode.h"
24 #include "util/container.h"
25 
26 class Map;
27 class ServerMap;
28 class MapBlock;
29 class MMVManip;
30 
31 namespace voxalgo
32 {
33 
34 /*!
35  * Updates the lighting on the map.
36  * The result will be correct only if
37  * no nodes were changed except the given ones.
38  * Before calling this procedure make sure that all new nodes on
39  * the map have zero light level!
40  *
41  * \param oldnodes contains the MapNodes that were replaced by the new
42  * MapNodes and their positions
43  * \param modified_blocks output, contains all map blocks that
44  * the function modified
45  */
46 void update_lighting_nodes(
47 	Map *map,
48 	std::vector<std::pair<v3s16, MapNode> > &oldnodes,
49 	std::map<v3s16, MapBlock*> &modified_blocks);
50 
51 /*!
52  * Updates borders of the given mapblock.
53  * Only updates if the block was marked with incomplete
54  * lighting and the neighbor is also loaded.
55  *
56  * \param block the block to update
57  * \param modified_blocks output, contains all map blocks that
58  * the function modified
59  */
60 void update_block_border_lighting(Map *map, MapBlock *block,
61 	std::map<v3s16, MapBlock*> &modified_blocks);
62 
63 /*!
64  * Copies back nodes from a voxel manipulator
65  * to the map and updates lighting.
66  * For server use only.
67  *
68  * \param modified_blocks output, contains all map blocks that
69  * the function modified
70  */
71 void blit_back_with_light(ServerMap *map, MMVManip *vm,
72 	std::map<v3s16, MapBlock*> *modified_blocks);
73 
74 /*!
75  * Corrects the light in a map block.
76  * For server use only.
77  *
78  * \param block the block to update
79  */
80 void repair_block_light(ServerMap *map, MapBlock *block,
81 	std::map<v3s16, MapBlock*> *modified_blocks);
82 
83 /*!
84  * This class iterates trough voxels that intersect with
85  * a line. The collision detection does not see nodeboxes,
86  * every voxel is a cube and is returned.
87  * This iterator steps to all nodes exactly once.
88  */
89 struct VoxelLineIterator
90 {
91 public:
92 	//! Starting position of the line in world coordinates.
93 	v3f m_start_position;
94 	//! Direction and length of the line in world coordinates.
95 	v3f m_line_vector;
96 	/*!
97 	 * Each component stores the next smallest positive number, by
98 	 * which multiplying the line's vector gives a vector that ends
99 	 * on the intersection of two nodes.
100 	 */
101 	v3f m_next_intersection_multi { 10000.0f, 10000.0f, 10000.0f };
102 	/*!
103 	 * Each component stores the smallest positive number, by which
104 	 * m_next_intersection_multi's components can be increased.
105 	 */
106 	v3f m_intersection_multi_inc { 10000.0f, 10000.0f, 10000.0f };
107 	/*!
108 	 * Direction of the line. Each component can be -1 or 1 (if a
109 	 * component of the line's vector is 0, then there will be 1).
110 	 */
111 	v3s16 m_step_directions { 1, 1, 1 };
112 	//! Position of the current node.
113 	v3s16 m_current_node_pos;
114 	//! Index of the current node
115 	s16 m_current_index = 0;
116 	//! Position of the start node.
117 	v3s16 m_start_node_pos;
118 	//! Index of the last node
119 	s16 m_last_index;
120 
121 	/*!
122 	 * Creates a voxel line iterator with the given line.
123 	 * @param start_position starting point of the line
124 	 * in voxel coordinates
125 	 * @param line_vector    length and direction of the
126 	 * line in voxel coordinates. start_position+line_vector
127 	 * is the end of the line
128 	 */
129 	VoxelLineIterator(const v3f &start_position,const v3f &line_vector);
130 
131 	/*!
132 	 * Steps to the next voxel.
133 	 * Updates m_current_node_pos and
134 	 * m_previous_node_pos.
135 	 * Note that it works even if hasNext() is false,
136 	 * continuing the line as a ray.
137 	 */
138 	void next();
139 
140 	/*!
141 	 * Returns true if the next voxel intersects the given line.
142 	 */
hasNextVoxelLineIterator143 	inline bool hasNext() const
144 	{
145 		return m_current_index < m_last_index;
146 	}
147 
148 	/*!
149 	 * Returns how many times next() must be called until
150 	 * voxel==m_current_node_pos.
151 	 * If voxel does not intersect with the line,
152 	 * the result is undefined.
153 	 */
154 	s16 getIndex(v3s16 voxel);
155 };
156 
157 } // namespace voxalgo
158