1 package org.opentrafficsim.road.gtu.lane.perception;
2
3 import org.djunits.value.vdouble.scalar.Length;
4
5 /**
6 * This data structure can clearly indicate the lane structure ahead of us, e.g. in the following situation:
7 *
8 * <pre>
9 * (---- a ----)(---- b ----)(---- c ----)(---- d ----)(---- e ----)(---- f ----)(---- g ----)
10 * __________ __________
11 * / _________ 1 / _________ 2
12 * / / / /
13 * __________/ / _______________________/ /
14 * 1 ____________ ____________ /_ _ _ _ _ _/____________ /_ _ _ _ _ _ _ _ _ _ _ _ /
15 * 0 |_ _X_ _ _ _ |_ _ _ _ _ _ |_ _ _ _ _ _ |_ _ _ _ _ _ |_ _ _ _ _ _ |_ _ _ _ _ _ \____________
16 * -1 |____________|_ _ _ _ _ _ |____________|____________| __________|____________|____________| 3
17 * -2 / __________/ \ \
18 * ________/ / \ \___________
19 * 5 _________/ \____________ 4
20 * </pre>
21 *
22 * When the GTU is looking ahead, it needs to know that when it continues to destination 3, it needs to shift one lane to the
23 * right at some point, but <b>not</b> two lanes to the right in link b, and not later than at the end of link f. When it needs
24 * to go to destination 1, it needs to shift to the left in link c. When it has to go to destination 2, it has to shift to the
25 * left, but not earlier than at link e. At node [de], it is possible to leave the rightmost lane of link e, and go to
26 * destination 4. The rightmost lane just splits into two lanes at the end of link d, and the GTU can either continue driving to
27 * destination 3, turn right to destination 4. This means that the right lane of link d has <b>two</b> successor lanes.
28 * <p>
29 * In the data structures, lanes are numbered laterally. Suppose that the lane where vehicle X resides would be number 0.
30 * Consistent with "left is positive" for angles, the lane right of X would have number -1, and entry 5 would have number -2.
31 * <p>
32 * In the data structure, this can be indicated as follows (N = next, P = previous, L = left, R = right, D = lane drop, . =
33 * continued but not in this structure). The merge lane in b is considered "off limits" for the GTUs on the "main" lane -1; the
34 * "main" lane 0 is considered off limits from the exit lanes on c, e, and f. Still, we need to maintain pointers to these
35 * lanes, as we are interested in the GTUs potentially driving next to us, feeding into our lane, etc.
36 *
37 * <pre>
38 * 1 0 -1 -2
39 *
40 * ROOT
41 * _____|_____ ___________ ___________
42 * |_-_|_._|_R_|----|_L_|_._|_-_| |_-_|_._|_-_| a
43 * | | |
44 * _____V_____ _____V_____ _____V_____
45 * |_-_|_N_|_R_|----|_L_|_N_|_R_|<---|_L_|_D_|_-_| b
46 * | |
47 * ___________ _____V_____ _____V_____
48 * |_-_|_N_|_R_|<---|_L_|_N_|_R_|----|_L_|_N_|_-_| c
49 * | | |
50 * _____V_____ _____V_____ _____V_____
51 * |_-_|_._|_-_| |_-_|_N_|_R_|----|_L_|_NN|_-_| d
52 * | ||_______________
53 * ___________ _____V_____ _____V_____ _____V_____
54 * |_-_|_N_|_R_|<---|_L_|_N_|_R_|----|_L_|_N_|_-_| |_-_|_N_|_-_| e
55 * | | | |
56 * _____V_____ _____V_____ _____V_____ _____V_____
57 * |_-_|_N_|_R_|<---|_L_|_D_|_R_|----|_L_|_N_|_-_| |_-_|_._|_-_| f
58 * | |
59 * _____V_____ _____V_____
60 * |_-_|_._|_-_| |_-_|_._|_-_| g
61 *
62 *
63 * </pre>
64 * <p>
65 * Copyright (c) 2013-2015 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
66 * BSD-style license. See <a href="http://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
67 * </p>
68 * $LastChangedDate: 2015-07-24 02:58:59 +0200 (Fri, 24 Jul 2015) $, @version $Revision: 1147 $, by $Author: averbraeck $,
69 * initial version Feb 20, 2016 <br>
70 * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
71 */
72 public class LaneStructure
73 {
74 /** The length of this structure, to see if it needs updating. */
75 private Length.Rel length;
76
77 /** The lanes from which we observe the situation. */
78 private LaneStructureRecord rootLSR;
79
80 /**
81 * @param initialRootLSR the initial rot record.
82 *
83 */
84 public LaneStructure(final LaneStructureRecord initialRootLSR)
85 {
86 setRootLSR(initialRootLSR);
87 }
88
89 /**
90 * @return rootLSR
91 */
92 public final LaneStructureRecord getRootLSR()
93 {
94 return this.rootLSR;
95 }
96
97 /**
98 * @param rootLSR set rootLSR
99 */
100 public final void setRootLSR(final LaneStructureRecord rootLSR)
101 {
102 this.rootLSR = rootLSR;
103 }
104
105 /**
106 * @return length
107 */
108 public final Length.Rel getLength()
109 {
110 return this.length;
111 }
112
113 }