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to add two kinds of Penrose tiling to the grid types supported by Loopy. This has involved a certain amount of infrastructure work, because of course the whole point of Penrose tilings is that they don't have to be the same every time: so now grid.c has grown the capacity to describe its grids as strings, and reconstitute them from those string descriptions. Hence a Penrose Loopy game description consists of a string identifying a particular piece of Penrose tiling, followed by the normal Loopy clue encoding. All the existing grid types decline to provide a grid description string, so their Loopy game descriptions have not changed encoding. [originally from svn r9159]
132 lines
4.6 KiB
C
132 lines
4.6 KiB
C
/*
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* (c) Lambros Lambrou 2008
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*
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* Code for working with general grids, which can be any planar graph
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* with faces, edges and vertices (dots). Includes generators for a few
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* types of grid, including square, hexagonal, triangular and others.
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*/
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#ifndef PUZZLES_GRID_H
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#define PUZZLES_GRID_H
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#include "puzzles.h" /* for random_state */
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/* Useful macros */
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#define SQ(x) ( (x) * (x) )
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/* ----------------------------------------------------------------------
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* Grid structures:
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* A grid is made up of faces, edges and dots. These structures hold
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* the incidence relationships between these types. For example, an
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* edge always joins two dots, and is adjacent to two faces.
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* The "grid_xxx **" members are lists of pointers which are dynamically
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* allocated during grid generation.
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* A pointer to a face/edge/dot will always point somewhere inside one of the
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* three lists of the main "grid" structure: faces, edges, dots.
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* Could have used integer offsets into these lists, but using actual
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* pointers instead gives us type-safety.
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*/
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/* Need forward declarations */
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typedef struct grid_face grid_face;
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typedef struct grid_edge grid_edge;
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typedef struct grid_dot grid_dot;
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struct grid_face {
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int order; /* Number of edges, also the number of dots */
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grid_edge **edges; /* edges around this face */
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grid_dot **dots; /* corners of this face */
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/*
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* For each face, we optionally compute and store its 'incentre'.
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* The incentre of a triangle is the centre of a circle tangent to
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* all three edges; I generalise the concept to arbitrary polygons
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* by defining it to be the centre of the largest circle you can fit
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* anywhere in the polygon. It's a useful thing to know because if
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* you want to draw any symbol or text in the face (e.g. clue
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* numbers in Loopy), that's the place it will most easily fit.
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*
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* When a grid is first generated, no face has this information
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* computed, because it's fiddly to do. You can call
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* grid_find_incentre() on a face, and it will fill in ix,iy below
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* and set has_incentre to indicate that it's done so.
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*/
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int has_incentre;
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int ix, iy; /* incentre (centre of largest inscribed circle) */
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};
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struct grid_edge {
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grid_dot *dot1, *dot2;
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grid_face *face1, *face2; /* Use NULL for the infinite outside face */
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};
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struct grid_dot {
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int order;
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grid_edge **edges;
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grid_face **faces; /* A NULL grid_face* means infinite outside face */
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/* Position in some fairly arbitrary (Cartesian) coordinate system.
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* Use large enough values such that we can get away with
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* integer arithmetic, but small enough such that arithmetic
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* won't overflow. */
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int x, y;
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};
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typedef struct grid {
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/* These are (dynamically allocated) arrays of all the
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* faces, edges, dots that are in the grid. */
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int num_faces; grid_face *faces;
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int num_edges; grid_edge *edges;
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int num_dots; grid_dot *dots;
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/* Cache the bounding-box of the grid, so the drawing-code can quickly
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* figure out the proper scaling to draw onto a given area. */
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int lowest_x, lowest_y, highest_x, highest_y;
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/* A measure of tile size for this grid (in grid coordinates), to help
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* the renderer decide how large to draw the grid.
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* Roughly the size of a single tile - for example the side-length
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* of a square cell. */
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int tilesize;
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/* We really don't want to copy this monstrosity!
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* A grid is immutable once generated.
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*/
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int refcount;
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} grid;
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/* Grids are specified by type: GRID_SQUARE, GRID_KITE, etc. */
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#define GRIDGEN_LIST(A) \
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A(SQUARE,square) \
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A(HONEYCOMB,honeycomb) \
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A(TRIANGULAR,triangular) \
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A(SNUBSQUARE,snubsquare) \
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A(CAIRO,cairo) \
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A(GREATHEXAGONAL,greathexagonal) \
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A(OCTAGONAL,octagonal) \
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A(KITE,kites) \
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A(FLORET,floret) \
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A(DODECAGONAL,dodecagonal) \
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A(GREATDODECAGONAL,greatdodecagonal) \
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A(PENROSE_P2,penrose_p2_kite) \
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A(PENROSE_P3,penrose_p3_thick)
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#define ENUM(upper,lower) GRID_ ## upper,
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typedef enum grid_type { GRIDGEN_LIST(ENUM) GRID_TYPE_MAX } grid_type;
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#undef ENUM
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/* Free directly after use if non-NULL. Will never contain an underscore
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* (so clients can safely use that as a separator). */
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char *grid_new_desc(grid_type type, int width, int height, random_state *rs);
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char *grid_validate_desc(grid_type type, int width, int height, char *desc);
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grid *grid_new(grid_type type, int width, int height, char *desc);
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void grid_free(grid *g);
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grid_edge *grid_nearest_edge(grid *g, int x, int y);
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void grid_compute_size(grid_type type, int width, int height,
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int *tilesize, int *xextent, int *yextent);
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void grid_find_incentre(grid_face *f);
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#endif /* PUZZLES_GRID_H */
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