/*
* Copyright (C) 2006, Greg McIntyre
* All rights reserved. See the file named COPYING in the distribution
* for more details.
*/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#define __USE_ISOC99 1
#include <math.h>
#include <float.h>
#include <assert.h>
#include "fov.h"
/*
+---++---++---++---+
| || || || |
| || || || |
| || || || |
+---++---++---++---+ 2
+---++---++---+#####
| || || |#####
| || || |#####
| || || |#####
+---++---++---+#####X 1 <-- y
+---++---++---++---+
| || || || |
| @ || || || | <-- srcy centre -> dy = 0.5 = y - 0.5
| || || || |
+---++---++---++---+ 0
0 1 2 3 4
^ ^
| |
srcx x -> dx = 3.5 = x + 0.5
centre
Slope from @ to X.
+---++---++---++---+
| || || || |
| || || || |
| || || || |
+---++---++---++---+ 2
+---++---++---++---+
| || || || |
| || || || |
| || || || |
+---++---++---+X---+ 1 <-- y
+---++---++---+#####
| || || |#####
| @ || || |##### <-- srcy centre -> dy = 0.5 = y - 0.5
| || || |#####
+---++---++---+##### 0
0 1 2 3
^ ^
| |
srcx x -> dx = 2.5 = x - 0.5
centre
Slope from @ to X
*/
/* Types ---------------------------------------------------------- */
/** \cond INTERNAL */
typedef struct {
/*@observer@*/ fov_settings_type *settings;
/*@observer@*/ void *map;
/*@observer@*/ void *source;
int source_x;
int source_y;
unsigned radius;
} fov_private_data_type;
/** \endcond */
/* Options -------------------------------------------------------- */
void fov_settings_init(fov_settings_type *settings) {
settings->shape = FOV_SHAPE_CIRCLE_PRECALCULATE;
settings->corner_peek = FOV_CORNER_NOPEEK;
settings->opaque_apply = FOV_OPAQUE_APPLY;
settings->opaque = NULL;
settings->apply = NULL;
settings->heights = NULL;
settings->numheights = 0;
}
void fov_settings_set_shape(fov_settings_type *settings,
fov_shape_type value) {
settings->shape = value;
}
void fov_settings_set_corner_peek(fov_settings_type *settings,
fov_corner_peek_type value) {
settings->corner_peek = value;
}
void fov_settings_set_opaque_apply(fov_settings_type *settings,
fov_opaque_apply_type value) {
settings->opaque_apply = value;
}
void fov_settings_set_opacity_test_function(fov_settings_type *settings,
bool (*f)(void *map,
int x, int y)) {
settings->opaque = f;
}
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)) {
settings->apply = f;
}
/* Circular FOV --------------------------------------------------- */
/*@null@*/ static unsigned *precalculate_heights(unsigned maxdist) {
unsigned i;
unsigned *result = (unsigned *)malloc((maxdist+2)*sizeof(unsigned));
if (result) {
for (i = 0; i <= maxdist; ++i) {
result[i] = (unsigned)sqrtf((float)(maxdist*maxdist - i*i));
}
result[maxdist+1] = 0;
}
return result;
}
static unsigned height(fov_settings_type *settings, int x,
unsigned maxdist) {
unsigned **newheights;
if (maxdist > settings->numheights) {
newheights = (unsigned **)calloc((size_t)maxdist, sizeof(unsigned*));
if (newheights != NULL) {
if (settings->heights != NULL && settings->numheights > 0) {
/* Copy the pointers to the heights arrays we've already
* calculated. Once copied out, we can free the old
* array of pointers. */
memcpy(newheights, settings->heights,
settings->numheights*sizeof(unsigned*));
free(settings->heights);
}
settings->heights = newheights;
settings->numheights = maxdist;
}
}
if (settings->heights) {
if (settings->heights[maxdist-1] == NULL) {
settings->heights[maxdist-1] = precalculate_heights(maxdist);
}
if (settings->heights[maxdist-1] != NULL) {
return settings->heights[maxdist-1][abs(x)];
}
}
return 0;
}
void fov_settings_free(fov_settings_type *settings) {
unsigned i;
if (settings != NULL) {
if (settings->heights != NULL && settings->numheights > 0) {
/*@+forloopexec@*/
for (i = 0; i < settings->numheights; ++i) {
unsigned *h = settings->heights[i];
if (h != NULL) {
free(h);
}
settings->heights[i] = NULL;
}
/*@=forloopexec@*/
free(settings->heights);
settings->heights = NULL;
settings->numheights = 0;
}
}
}
/* Slope ---------------------------------------------------------- */
static float fov_slope(float dx, float dy) {
if (dx <= -FLT_EPSILON || dx >= FLT_EPSILON) {
return dy/dx;
} else {
return 0.0;
}
}
/* Octants -------------------------------------------------------- */
#define FOV_DEFINE_OCTANT(signx, signy, rx, ry, nx, ny, nf, apply_edge, apply_diag) \
static void fov_octant_##nx##ny##nf( \
fov_private_data_type *data, \
int dx, \
float start_slope, \
float end_slope) { \
int x, y, dy, dy0, dy1; \
unsigned h; \
int prev_blocked = -1; \
float end_slope_next; \
fov_settings_type *settings = data->settings; \
\
if (dx == 0) { \
fov_octant_##nx##ny##nf(data, dx+1, start_slope, end_slope); \
return; \
} else if ((unsigned)dx > data->radius) { \
return; \
} \
\
dy0 = (int)(0.5f + ((float)dx)*start_slope); \
dy1 = (int)(0.5f + ((float)dx)*end_slope); \
\
rx = data->source_##rx signx dx; \
ry = data->source_##ry signy dy0; \
\
if (!apply_diag && dy1 == dx) { \
/* We do diagonal lines on every second octant, so they don't get done twice. */ \
--dy1; \
} \
\
switch (settings->shape) { \
case FOV_SHAPE_CIRCLE_PRECALCULATE: \
h = height(settings, dx, data->radius); \
break; \
case FOV_SHAPE_CIRCLE: \
h = (unsigned)sqrtf((float)(data->radius*data->radius - dx*dx)); \
break; \
case FOV_SHAPE_OCTAGON: \
h = (data->radius - dx)<<1; \
break; \
default: \
h = data->radius; \
break; \
}; \
if ((unsigned)dy1 > h) { \
if (h == 0) { \
return; \
} \
dy1 = (int)h; \
} \
\
/*fprintf(stderr, "(%2d) = [%2d .. %2d] (%f .. %f), h=%d,edge=%d\n", \
dx, dy0, dy1, ((float)dx)*start_slope, \
0.5f + ((float)dx)*end_slope, h, apply_edge);*/ \
\
for (dy = dy0; dy <= dy1; ++dy) { \
ry = data->source_##ry signy dy; \
\
if (settings->opaque(data->map, x, y)) { \
if (settings->opaque_apply == FOV_OPAQUE_APPLY && (apply_edge || dy > 0)) { \
settings->apply(data->map, x, y, x - data->source_x, y - data->source_y, data->source); \
} \
if (prev_blocked == 0) { \
end_slope_next = fov_slope((float)dx + 0.5f, (float)dy - 0.5f); \
fov_octant_##nx##ny##nf(data, dx+1, start_slope, end_slope_next); \
} \
prev_blocked = 1; \
} else { \
if (apply_edge || dy > 0) { \
settings->apply(data->map, x, y, x - data->source_x, y - data->source_y, data->source); \
} \
if (prev_blocked == 1) { \
start_slope = fov_slope((float)dx - 0.5f, (float)dy - 0.5f); \
} \
prev_blocked = 0; \
} \
} \
\
if (prev_blocked == 0) { \
fov_octant_##nx##ny##nf(data, dx+1, start_slope, end_slope); \
} \
}
FOV_DEFINE_OCTANT(+,+,x,y,p,p,n,true,true)
FOV_DEFINE_OCTANT(+,+,y,x,p,p,y,true,false)
FOV_DEFINE_OCTANT(+,-,x,y,p,m,n,false,true)
FOV_DEFINE_OCTANT(+,-,y,x,p,m,y,false,false)
FOV_DEFINE_OCTANT(-,+,x,y,m,p,n,true,true)
FOV_DEFINE_OCTANT(-,+,y,x,m,p,y,true,false)
FOV_DEFINE_OCTANT(-,-,x,y,m,m,n,false,true)
FOV_DEFINE_OCTANT(-,-,y,x,m,m,y,false,false)
/* Circle --------------------------------------------------------- */
static void _fov_circle(fov_private_data_type *data) {
/*
* Octants are defined by (x,y,r) where:
* x = [p]ositive or [n]egative x increment
* y = [p]ositive or [n]egative y increment
* r = [y]es or [n]o for reflecting on axis x = y
*
* \pmy|ppy/
* \ | /
* \ | /
* mpn\|/ppn
* ----@----
* mmn/|\pmn
* / | \
* / | \
* /mmy|mpy\
*/
fov_octant_ppn(data, 1, (float)0.0f, (float)1.0f);
fov_octant_ppy(data, 1, (float)0.0f, (float)1.0f);
fov_octant_pmn(data, 1, (float)0.0f, (float)1.0f);
fov_octant_pmy(data, 1, (float)0.0f, (float)1.0f);
fov_octant_mpn(data, 1, (float)0.0f, (float)1.0f);
fov_octant_mpy(data, 1, (float)0.0f, (float)1.0f);
fov_octant_mmn(data, 1, (float)0.0f, (float)1.0f);
fov_octant_mmy(data, 1, (float)0.0f, (float)1.0f);
}
void fov_circle(fov_settings_type *settings,
void *map,
void *source,
int source_x,
int source_y,
unsigned radius) {
fov_private_data_type data;
data.settings = settings;
data.map = map;
data.source = source;
data.source_x = source_x;
data.source_y = source_y;
data.radius = radius;
_fov_circle(&data);
}
/**
* Limit x to the range [a, b].
*/
static float betweenf(float x, float a, float b) {
if (x - a < FLT_EPSILON) { /* x < a */
return a;
} else if (x - b > FLT_EPSILON) { /* x > b */
return b;
} else {
return x;
}
}
#define BEAM_DIRECTION(d, p1, p2, p3, p4, p5, p6, p7, p8) \
if (direction == d) { \
end_slope = betweenf(a, 0.0f, 1.0f); \
fov_octant_##p1(&data, 1, 0.0f, end_slope); \
fov_octant_##p2(&data, 1, 0.0f, end_slope); \
if (a - 1.0f > FLT_EPSILON) { /* a > 1.0f */ \
start_slope = betweenf(2.0f - a, 0.0f, 1.0f); \
fov_octant_##p3(&data, 1, start_slope, 1.0f); \
fov_octant_##p4(&data, 1, start_slope, 1.0f); \
} \
if (a - 2.0f > FLT_EPSILON) { /* a > 2.0f */ \
end_slope = betweenf(a - 2.0f, 0.0f, 1.0f); \
fov_octant_##p5(&data, 1, 0.0f, end_slope); \
fov_octant_##p6(&data, 1, 0.0f, end_slope); \
} \
if (a - 3.0f > FLT_EPSILON) { /* a > 3.0f */ \
start_slope = betweenf(4.0f - a, 0.0f, 1.0f); \
fov_octant_##p7(&data, 1, start_slope, 1.0f); \
fov_octant_##p8(&data, 1, start_slope, 1.0f); \
} \
}
#define BEAM_DIRECTION_DIAG(d, p1, p2, p3, p4, p5, p6, p7, p8) \
if (direction == d) { \
start_slope = betweenf(1.0f - a, 0.0f, 1.0f); \
fov_octant_##p1(&data, 1, start_slope, 1.0f); \
fov_octant_##p2(&data, 1, start_slope, 1.0f); \
if (a - 1.0f > FLT_EPSILON) { /* a > 1.0f */ \
end_slope = betweenf(a - 1.0f, 0.0f, 1.0f); \
fov_octant_##p3(&data, 1, 0.0f, end_slope); \
fov_octant_##p4(&data, 1, 0.0f, end_slope); \
} \
if (a - 2.0f > FLT_EPSILON) { /* a > 2.0f */ \
start_slope = betweenf(3.0f - a, 0.0f, 1.0f); \
fov_octant_##p5(&data, 1, start_slope, 1.0f); \
fov_octant_##p6(&data, 1, start_slope, 1.0f); \
} \
if (a - 3.0f > FLT_EPSILON) { /* a > 3.0f */ \
end_slope = betweenf(a - 3.0f, 0.0f, 1.0f); \
fov_octant_##p7(&data, 1, 0.0f, end_slope); \
fov_octant_##p8(&data, 1, 0.0f, end_slope); \
} \
}
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) {
fov_private_data_type data;
float start_slope, end_slope, a;
data.settings = settings;
data.map = map;
data.source = source;
data.source_x = source_x;
data.source_y = source_y;
data.radius = radius;
if (angle <= 0.0f) {
return;
} else if (angle >= 360.0f) {
_fov_circle(&data);
return;
}
/* Calculate the angle as a percentage of 45 degrees, halved (for
* each side of the centre of the beam). e.g. angle = 180.0f means
* half the beam is 90.0 which is 2x45, so the result is 2.0.
*/
a = angle/90.0f;
BEAM_DIRECTION(FOV_EAST, ppn, pmn, ppy, mpy, pmy, mmy, mpn, mmn);
BEAM_DIRECTION(FOV_WEST, mpn, mmn, pmy, mmy, ppy, mpy, ppn, pmn);
BEAM_DIRECTION(FOV_NORTH, mpy, mmy, mmn, pmn, mpn, ppn, pmy, ppy);
BEAM_DIRECTION(FOV_SOUTH, pmy, ppy, mpn, ppn, mmn, pmn, mmy, mpy);
BEAM_DIRECTION_DIAG(FOV_NORTHEAST, pmn, mpy, mmy, ppn, mmn, ppy, mpn, pmy);
BEAM_DIRECTION_DIAG(FOV_NORTHWEST, mmn, mmy, mpn, mpy, pmy, pmn, ppy, ppn);
BEAM_DIRECTION_DIAG(FOV_SOUTHEAST, ppn, ppy, pmy, pmn, mpn, mpy, mmn, mmy);
BEAM_DIRECTION_DIAG(FOV_SOUTHWEST, pmy, mpn, ppy, mmn, ppn, mmy, pmn, mpy);
}