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/*
* Copyright (C) 2006-2007, Greg McIntyre. All rights reserved. See the file
* named COPYING in the distribution for more details.
*/
/**
* \mainpage Field of View Library
*
* \section about About
*
* This is a C library which implements a course-grained lighting
* algorithm suitable for tile-based games such as roguelikes.
*
* \section copyright Copyright
*
* \verbinclude COPYING
*
* \section thanks Thanks
*
* Thanks to Björn Bergström
* <bjorn.bergstrom@hyperisland.se> for the algorithm.
*
*/
/**
* \file fov.h
* Field-of-view algorithm for dynamically casting light/shadow on a
* low resolution 2D raster.
*/
#ifndef LIBFOV_HEADER
#define LIBFOV_HEADER
#include <stdbool.h>
#include <stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
/** Eight-way directions. */
typedef enum {
FOV_EAST = 0,
FOV_NORTHEAST,
FOV_NORTH,
FOV_NORTHWEST,
FOV_WEST,
FOV_SOUTHWEST,
FOV_SOUTH,
FOV_SOUTHEAST
} fov_direction_type;
/** Values for the shape setting. */
typedef enum {
FOV_SHAPE_CIRCLE_PRECALCULATE,
FOV_SHAPE_SQUARE,
FOV_SHAPE_CIRCLE,
FOV_SHAPE_OCTAGON
} fov_shape_type;
/** Values for the corner peek setting. */
typedef enum {
FOV_CORNER_NOPEEK,
FOV_CORNER_PEEK
} fov_corner_peek_type;
/** Values for the opaque apply setting. */
typedef enum {
FOV_OPAQUE_APPLY,
FOV_OPAQUE_NOAPPLY
} fov_opaque_apply_type;
/** @cond INTERNAL */
typedef /*@null@*/ unsigned *height_array_t;
/** @endcond */
typedef struct {
/** Opacity test callback. */
/*@null@*/ bool (*opaque)(void *map, int x, int y);
/** Lighting callback to set lighting on a map tile. */
/*@null@*/ void (*apply)(void *map, int x, int y, int dx, int dy, void *src);
/** Shape setting. */
fov_shape_type shape;
/** Whether to peek around corners. */
fov_corner_peek_type corner_peek;
/** Whether to call apply on opaque tiles. */
fov_opaque_apply_type opaque_apply;
/** \cond INTERNAL */
/** Pre-calculated data. \internal */
/*@null@*/ height_array_t *heights;
/** Size of pre-calculated data. \internal */
unsigned numheights;
/** \endcond */
} fov_settings_type;
/** The opposite direction to that given. */
#define fov_direction_opposite(direction) ((fov_direction_type)(((direction)+4)&0x7))
/**
* Set all the default options. You must call this option when you
* create a new settings data structure.
*
* These settings are the defaults used:
*
* - shape: FOV_SHAPE_CIRCLE_PRECALCULATE
* - corner_peek: FOV_CORNER_NOPEEK
* - opaque_apply: FOV_OPAQUE_APPLY
*
* Callbacks still need to be set up after calling this function.
*
* \param settings Pointer to data structure containing settings.
*/
void fov_settings_init(fov_settings_type *settings);
/**
* Set the shape of the field of view.
*
* \param settings Pointer to data structure containing settings.
* \param value One of the following values, where R is the radius:
*
* - FOV_SHAPE_CIRCLE_PRECALCULATE \b (default): Limit the FOV to a
* circle with radius R by precalculating, which consumes more memory
* at the rate of 4*(R+2) bytes per R used in calls to fov_circle.
* Each radius is only calculated once so that it can be used again.
* Use fov_free() to free this precalculated data's memory.
*
* - FOV_SHAPE_CIRCLE: Limit the FOV to a circle with radius R by
* calculating on-the-fly.
*
* - FOV_SHAPE_OCTOGON: Limit the FOV to an octogon with maximum radius R.
*
* - FOV_SHAPE_SQUARE: Limit the FOV to an R*R square.
*/
void fov_settings_set_shape(fov_settings_type *settings, fov_shape_type value);
/**
* <em>NOT YET IMPLEMENTED</em>.
*
* Set whether sources will peek around corners.
*
* \param settings Pointer to data structure containing settings.
* \param value One of the following values:
*
* - FOV_CORNER_PEEK \b (default): Renders:
\verbatim
........
........
........
..@#
...#
\endverbatim
* - FOV_CORNER_NOPEEK: Renders:
\verbatim
......
.....
....
..@#
...#
\endverbatim
*/
void fov_settings_set_corner_peek(fov_settings_type *settings, fov_corner_peek_type value);
/**
* Whether to call the apply callback on opaque tiles.
*
* \param settings Pointer to data structure containing settings.
* \param value One of the following values:
*
* - FOV_OPAQUE_APPLY \b (default): Call apply callback on opaque tiles.
* - FOV_OPAQUE_NOAPPLY: Do not call the apply callback on opaque tiles.
*/
void fov_settings_set_opaque_apply(fov_settings_type *settings, fov_opaque_apply_type value);
/**
* Set the function used to test whether a map tile is opaque.
*
* \param settings Pointer to data structure containing settings.
* \param f The function called to test whether a map tile is opaque.
*/
void fov_settings_set_opacity_test_function(fov_settings_type *settings, bool (*f)(void *map, int x, int y));
/**
* Set the function used to apply lighting to a map tile.
*
* \param settings Pointer to data structure containing settings.
* \param f The function called to apply lighting to a map tile.
*/
void fov_settings_set_apply_lighting_function(fov_settings_type *settings, void (*f)(void *map, int x, int y, int dx, int dy, void *src));
/**
* Free any memory that may have been cached in the settings
* structure.
*
* \param settings Pointer to data structure containing settings.
*/
void fov_settings_free(fov_settings_type *settings);
/**
* Calculate a full circle field of view from a source at (x,y).
*
* \param settings Pointer to data structure containing settings.
* \param map Pointer to map data structure to be passed to callbacks.
* \param source Pointer to data structure holding source of light.
* \param source_x x-axis coordinate from which to start.
* \param source_y y-axis coordinate from which to start.
* \param radius Euclidean distance from (x,y) after which to stop.
*/
void fov_circle(fov_settings_type *settings, void *map, void *source,
int source_x, int source_y, unsigned radius
);
/**
* Calculate a field of view from source at (x,y), pointing
* in the given direction and with the given angle. The larger
* the angle, the wider, "less focused" the beam. Each side of the
* line pointing in the direction from the source will be half the
* angle given such that the angle specified will be represented on
* the raster.
*
* \param settings Pointer to data structure containing settings.
* \param map Pointer to map data structure to be passed to callbacks.
* \param source Pointer to data structure holding source of light.
* \param source_x x-axis coordinate from which to start.
* \param source_y y-axis coordinate from which to start.
* \param radius Euclidean distance from (x,y) after which to stop.
* \param direction One of eight directions the beam of light can point.
* \param angle The angle at the base of the beam of light, in degrees.
*/
void fov_beam(fov_settings_type *settings, void *map, void *source,
int source_x, int source_y, unsigned radius,
fov_direction_type direction, float angle
);
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif
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