1.开源库获取
地址：http://en.wikipedia.org/wiki/Visibility_graph
2. 使用
使用处包含头文件 #include "visilibity.hpp" 即可，以下面在Qt中使用为例：
1 /*
2 =========A VisiLibity Example Program=========
3 This program provides a text interface which will
4
5 (1) read an environment and guard locations from files given as
6 command line arguments,
7
8 (2) check the geometric validity of these inputs (edges of the
9 environment do not cross each other, guards are contained in the
10 environment, etc.),
11
12 (3) display environment and guards' data and statistics, and
13
14 (4) compute and display the visibility polygon of a guard chosen by
15 the user.
16
17 The environment representation and the guard locations can be read
18 from any files in the (human-readable) format demonstrated in
19 example.environment and example.guards.
20
21 Instructions: use the accompanying makefile to compile, then from
22 command line run
23 ./main [environment file] [guards file]
24 ,e.g., using the example files included with your VisiLibity download,
25 ./main example.environment example.guards
26 */
27
28 #include "visilibity.hpp" //VisiLibity header file
29 #include <cmath> //Puts math functions in std namespace
30 #include <cstdlib> //Gives rand, srand, exit
31 #include <cstring> //Gives C-string manipulation
32 #include <ctime> //Gives Unix time
33 #include <fstream> //File I/O
34 #include <iostream> //std I/O
35 #include <sstream> //Gives string streams
36 #include <string> //Gives string class
37 #include <vector> //std vectors
38 //#define NDEBUG //Turns off assert.
39 #include <cassert>
40
41 // ASCII escape sequences for colored terminal text.
42 std::string alert("\a"); // Beep
43 std::string normal("\x1b[0m"); // Designated fg color default bg color
44 std::string red("\x1b[31m");
45 std::string red_blink("\x1b[5;31m");
46 std::string black("\E[30;47m");
47 std::string green("\E[32m");
48 std::string yellow("\E[33;40m");
49 std::string blue("\E[34;47m");
50 std::string magenta("\x1b[35m");
51 std::string cyan("\E[36m");
52 std::string white_bold("\E[1;37;40m");
53 std::string clear_display("\E[2J");
54
55 //=========================Main=========================//
56 int main(int argc, char *argv[]) {
57 std::cout << argv[0] << std::endl;
58 std::cout << argv[1] << std::endl;
59 std::cout << argv[2] << std::endl;
60
61 // Check input validity
62 if (argc > 3) {
63 std::cerr << "Error: too many input arguments" << std::endl;
64 exit(1);
65 }
66
67 // Set iostream floating-point display format
68 const int IOS_PRECISION = 10;
69 std::cout.setf(std::ios::fixed);
70 std::cout.setf(std::ios::showpoint);
71 std::cout.precision(IOS_PRECISION);
72
73 // Seed the rand() fnc w/Unix time
74 //(only necessary once at the beginning of the program)
75 std::srand(std::time(NULL));
76 rand();
77
78 // Set geometric robustness constant
79 //:WARNING:
80 // may need to modify epsilon for Environments with greatly varying
81 // scale of features
82 double epsilon = 0.000000001;
83 std::cout << green << "The robustness constant epsilon is set to " << epsilon
84 << normal << std::endl;
85
86 /*----------Load Geometry from Files----------*/
87
88 // Load geometric environment model from file
89 std::cout << "Loading environment file ";
90 std::string environment_file(argv[1]);
91 // Print environment filename to screen
92 std::cout << environment_file << " . . . ";
93 // Construct Environment object from file
94 VisiLibity::Environment my_environment(environment_file);
95 std::cout << "OK" << std::endl;
96
97 // Load guard positions from file
98 std::cout << "Loading guards file ";
99 std::string guards_file(argv[2]);
100 // Print guards filename to screen
101 std::cout << guards_file << " . . . ";
102 // Construct Guards object from file
103 VisiLibity::Guards my_guards(guards_file);
104 std::cout << "OK" << std::endl;
105
106 /*----------Check Validity of Geometry----------*/
107
108 // Check Environment is epsilon-valid
109 std::cout << "Validating environment model . . . ";
110 if (my_environment.is_valid(epsilon))
111 std::cout << "OK" << std::endl;
112 else {
113 std::cout << std::endl
114 << red << "Warning: Environment model "
115 << "is invalid." << std::endl
116 << "A valid environment model must have" << std::endl
117 << " 1) outer boundary and holes pairwise "
118 << "epsilon -disjoint simple polygons" << std::endl
119 << " (no two features should come "
120 << "within epsilon of each other)," << std::endl
121 << " 2) outer boundary is oriented ccw, and" << std::endl
122 << " 3) holes are oriented cw." << std::endl
123 << normal;
124 exit(1);
125 }
126
127 // Check Guards are all in the Environment
128 std::cout << "Checking all guards are "
129 << "in the environment and noncolocated . . . ";
130 my_guards.snap_to_boundary_of(my_environment, epsilon);
131 my_guards.snap_to_vertices_of(my_environment, epsilon);
132 for (unsigned i = 0; i < my_guards.N(); i++) {
133 if (!my_guards[i].in(my_environment, epsilon)) {
134 std::cout << std::endl
135 << red << "Warning: guard " << i << " not in the environment."
136 << normal << std::endl;
137 exit(1);
138 }
139 }
140 if (!my_guards.noncolocated(epsilon)) {
141 std::cout << std::endl
142 << red << "Warning: Some guards are colocated." << normal
143 << std::endl;
144 exit(1);
145 } else
146 std::cout << "OK" << std::endl;
147
148 /*----------Print Data and Statistics to Screen----------*/
149
150 // Environment data
151 std::cout << "The environment model is:" << std::endl;
152 std::cout << magenta << my_environment << normal;
153
154 // Environment stats
155 std::cout << "This environment has " << cyan << my_environment.n()
156 << " vertices, " << my_environment.r() << " reflex vertices, "
157 << my_environment.h() << " holes, "
158 << "area " << my_environment.area() << ", "
159 << "boundary length " << my_environment.boundary_length() << ", "
160 << "diameter " << my_environment.diameter() << "." << normal
161 << std::endl;
162
163 // Guards data
164 std::cout << "The guards' positions are:" << std::endl;
165 std::cout << magenta << my_guards << normal;
166
167 // Guards stats
168 std::cout << "There are " << cyan << my_guards.N() << " guards." << normal
169 << std::endl;
170
171 /*----------Compute the Visibility Polygon
172 of a Guard Chosen by User----------*/
173
174 // Prompt user
175 int guard_choice(0);
176 std::cout << "Which guard would you like "
177 << "to compute the visibility polygon of "
178 << "(0, 1, 2, ...)? " << std::endl;
179 std::cin >> guard_choice;
180 std::cout << normal;
181
182 // Compute and display visibility polygon
183 VisiLibity::Visibility_Polygon my_visibility_polygon(my_guards[guard_choice],
184 my_environment, epsilon);
185 std::cout << "The visibility polygon is" << std::endl
186 << magenta << my_visibility_polygon << normal << std::endl;
187
188 /*
189 //To save the visibility polygon in an Environment file
190 VisiLibity::Environment(my_visibility_polygon)
191 .write_to_file("./example_visibility_polygon.cin", IOS_PRECISION);
192 */
193
194 return 0;
195 }
View Code
注：运行时需要将两个输入文件添加到运行参数同时将这两个文件放入到运行目录。
example1.environment文件说明：
example1.guards文件说明：
运行程序结果：
标签：std,environment,图论,string,C++,---,guards,include,Gives From： https://www.cnblogs.com/henkk/p/17983938