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1 | /* |
2 | * (c) Lambros Lambrou 2008 |
3 | * |
4 | * Code for working with general grids, which can be any planar graph |
5 | * with faces, edges and vertices (dots). Includes generators for a few |
6 | * types of grid, including square, hexagonal, triangular and others. |
7 | */ |
8 | |
9 | #ifndef PUZZLES_GRID_H |
10 | #define PUZZLES_GRID_H |
11 | |
12 | /* Useful macros */ |
1515b973 |
13 | #define SQ(x) ( (x) * (x) ) |
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14 | |
15 | /* ---------------------------------------------------------------------- |
16 | * Grid structures: |
17 | * A grid is made up of faces, edges and dots. These structures hold |
18 | * the incidence relationships between these types. For example, an |
19 | * edge always joins two dots, and is adjacent to two faces. |
20 | * The "grid_xxx **" members are lists of pointers which are dynamically |
21 | * allocated during grid generation. |
22 | * A pointer to a face/edge/dot will always point somewhere inside one of the |
23 | * three lists of the main "grid" structure: faces, edges, dots. |
24 | * Could have used integer offsets into these lists, but using actual |
25 | * pointers instead gives us type-safety. |
26 | */ |
27 | |
28 | /* Need forward declarations */ |
29 | typedef struct grid_face grid_face; |
30 | typedef struct grid_edge grid_edge; |
31 | typedef struct grid_dot grid_dot; |
32 | |
33 | struct grid_face { |
34 | int order; /* Number of edges, also the number of dots */ |
35 | grid_edge **edges; /* edges around this face */ |
36 | grid_dot **dots; /* corners of this face */ |
37 | }; |
38 | struct grid_edge { |
39 | grid_dot *dot1, *dot2; |
40 | grid_face *face1, *face2; /* Use NULL for the infinite outside face */ |
41 | }; |
42 | struct grid_dot { |
43 | int order; |
44 | grid_edge **edges; |
45 | grid_face **faces; /* A NULL grid_face* means infinite outside face */ |
46 | |
47 | /* Position in some fairly arbitrary (Cartesian) coordinate system. |
48 | * Use large enough values such that we can get away with |
49 | * integer arithmetic, but small enough such that arithmetic |
50 | * won't overflow. */ |
51 | int x, y; |
52 | }; |
53 | typedef struct grid { |
54 | /* These are (dynamically allocated) arrays of all the |
55 | * faces, edges, dots that are in the grid. */ |
56 | int num_faces; grid_face *faces; |
57 | int num_edges; grid_edge *edges; |
58 | int num_dots; grid_dot *dots; |
59 | |
60 | /* Should be a face roughly near the middle of the grid. |
61 | * Used to seed path-generation, and also for nearest-edge |
62 | * detection. */ |
63 | grid_face *middle_face; |
64 | |
65 | /* Cache the bounding-box of the grid, so the drawing-code can quickly |
66 | * figure out the proper scaling to draw onto a given area. */ |
67 | int lowest_x, lowest_y, highest_x, highest_y; |
68 | |
69 | /* A measure of tile size for this grid (in grid coordinates), to help |
70 | * the renderer decide how large to draw the grid. |
71 | * Roughly the size of a single tile - for example the side-length |
72 | * of a square cell. */ |
73 | int tilesize; |
74 | |
75 | /* We really don't want to copy this monstrosity! |
76 | * A grid is immutable once generated. |
77 | */ |
78 | int refcount; |
79 | } grid; |
80 | |
81 | grid *grid_new_square(int width, int height); |
82 | grid *grid_new_honeycomb(int width, int height); |
83 | grid *grid_new_triangular(int width, int height); |
84 | grid *grid_new_snubsquare(int width, int height); |
85 | grid *grid_new_cairo(int width, int height); |
86 | grid *grid_new_greathexagonal(int width, int height); |
87 | grid *grid_new_octagonal(int width, int height); |
88 | grid *grid_new_kites(int width, int height); |
89 | |
90 | void grid_free(grid *g); |
91 | |
92 | grid_edge *grid_nearest_edge(grid *g, int x, int y); |
93 | |
94 | #endif /* PUZZLES_GRID_H */ |