1function SetUpServer() {
2  TopHeader = "<HTML><title>Walk through a maze</title>"
3  TopDoc = "\
4    <h2>Please choose one of the following actions:</h2>\
5    <UL>\
6      <LI><A HREF=" MyPrefix "/AboutServer>About this server</A>\
7      <LI><A HREF=" MyPrefix "/VRMLtest>Watch a simple VRML scene</A>\
8    </UL>"
9  TopFooter  = "</HTML>"
10  srand()
11}
12function HandleGET() {
13  if (MENU[2] == "AboutServer") {
14    Document  = "If your browser has a VRML 2 plugin,\
15      this server shows you a simple VRML scene."
16  } else if (MENU[2] == "VRMLtest") {
17    XSIZE = YSIZE = 11              # initially, everything is wall
18    for (y = 0; y < YSIZE; y++)
19       for (x = 0; x < XSIZE; x++)
20          Maze[x, y] = "#"
21    delete Maze[0, 1]              # entry is not wall
22    delete Maze[XSIZE-1, YSIZE-2]  # exit  is not wall
23    MakeMaze(1, 1)
24    Document = "\
25#VRML V2.0 utf8\n\
26Group {\n\
27  children [\n\
28    PointLight {\n\
29      ambientIntensity 0.2\n\
30      color 0.7 0.7 0.7\n\
31      location 0.0 8.0 10.0\n\
32    }\n\
33    DEF B1 Background {\n\
34      skyColor [0 0 0, 1.0 1.0 1.0 ]\n\
35      skyAngle 1.6\n\
36      groundColor [1 1 1, 0.8 0.8 0.8, 0.2 0.2 0.2 ]\n\
37      groundAngle [ 1.2 1.57 ]\n\
38    }\n\
39    DEF Wall Shape {\n\
40      geometry Box {size 1 1 1}\n\
41      appearance Appearance { material Material { diffuseColor 0 0 1 } }\n\
42    }\n\
43    DEF Entry Viewpoint {\n\
44      position 0.5 1.0 5.0\n\
45      orientation 0.0 0.0 -1.0 0.52\n\
46    }\n"
47    for (i in Maze) {
48      split(i, t, SUBSEP)
49      Document = Document "    Transform { translation "
50      Document = Document t[1] " 0 -" t[2] " children USE Wall }\n"
51    }
52    Document = Document "  ] # end of group for world\n}"
53    Reason = "OK" ORS "Content-type: model/vrml"
54    Header = Footer = ""
55  }
56}
57function MakeMaze(x, y) {
58  delete Maze[x, y]     # here we are, we have no wall here
59  p = 0                 # count unvisited fields in all directions
60  if (x-2 SUBSEP y   in Maze) d[p++] = "-x"
61  if (x   SUBSEP y-2 in Maze) d[p++] = "-y"
62  if (x+2 SUBSEP y   in Maze) d[p++] = "+x"
63  if (x   SUBSEP y+2 in Maze) d[p++] = "+y"
64  if (p>0) {            # if there are unvisited fields, go there
65    p = int(p*rand())   # choose one unvisited field at random
66    if        (d[p] == "-x") { delete Maze[x - 1, y]; MakeMaze(x - 2, y)
67    } else if (d[p] == "-y") { delete Maze[x, y - 1]; MakeMaze(x, y - 2)
68    } else if (d[p] == "+x") { delete Maze[x + 1, y]; MakeMaze(x + 2, y)
69    } else if (d[p] == "+y") { delete Maze[x, y + 1]; MakeMaze(x, y + 2)
70    }                   # we are back from recursion
71    MakeMaze(x, y);     # try again while there are unvisited fields
72  }
73}
74