void fov_circle(fov_map_t* map, void* light_source,
int x, int y, int max_radius) {
int oct, r2;
r2 = max_radius * max_radius;
/* recursive shadow casting */
for (oct=0; oct < 8; ++oct) {
cast_light(map, light_source, y, x, 1, 1.0, 0.0, max_radius, r2,
mult[0][oct], mult[1][oct], mult[2][oct], mult[3][oct]);
}
map->apply(map, NULL, x, y);
}
static void cast_light(map_t *map,int cx, int cy,int row,float start, float end, int radius, int r2,
int xx, int xy, int yx, int yy, int id, bool light_walls) {
int j;
float new_start=0.0f;
if ( start < end ) return;
for (j=row; j< radius+1; j++) {
int dx=-j-1;
int dy=-j;
bool blocked=false;
while ( dx <= 0 ) {
int X,Y;
dx++;
X=cx+dx*xx+dy*xy;
Y=cy+dx*yx+dy*yy;
if ((unsigned)X < (unsigned)map->width && (unsigned)Y < (unsigned)map->height) {
float l_slope,r_slope;
int offset;
offset=X+Y*map->width;
l_slope=(dx-0.5f)/(dy+0.5f);
r_slope=(dx+0.5f)/(dy-0.5f);
if( start < r_slope ) continue;
else if( end > l_slope ) break;
if ( dx*dx+dy*dy <= r2
&& (light_walls || map->cells[offset].transparent)) map->cells[offset].fov=1;
if ( blocked ) {
if (!map->cells[offset].transparent) {
new_start=r_slope;
continue;
} else {
blocked=false;
start=new_start;
}
} else {
if (!map->cells[offset].transparent && j < radius ) {
blocked=true;
cast_light(map,cx,cy,j+1,start,l_slope,radius,r2,xx,xy,yx,yy,id+1,light_walls);
new_start=r_slope;
}
}
}
}
if ( blocked ) break;
}
}
static void cast_light(fov_map_t* map, void* light_source, int cx, int cy,
int row, float start, float end, int radius, int r2,
int xx, int xy, int yx, int yy) {
int j;
float new_start = 0.0f;
if(start < end) return;
for(j = row; j < radius + 1; j++) {
int dx = -j - 1;
int dy = -j;
int blocked = 0;
while(dx <= 0) {
int X, Y;
++dx;
X = cx + dx * xx + dy * xy;
Y = cy + dx * yx + dy * yy;
if(X < map->width && Y < map->height) {
float l_slope, r_slope;
l_slope = (dx - 0.5f) / (dy + 0.5f);
r_slope = (dx + 0.5f) / (dy - 0.5f);
if(start < r_slope) continue;
else if( end > l_slope ) break;
if(dx * dx + dy * dy <= r2) {
map->apply(map, NULL, X, Y);
}
if(blocked) {
if(map->blocked(map, X, Y)) {
new_start = r_slope;
continue;
} else {
blocked = 0;
start = new_start;
}
} else if(map->blocked(map, X, Y) && j < radius ) {
blocked = 1;
cast_light(map, light_source, cx, cy, j + 1, start, l_slope,
radius, r2, xx, xy, yx, yy);
new_start = r_slope;
}
}
}
if(blocked) break;
}
}
void TCOD_map_compute_fov_recursive_shadowcasting(TCOD_map_t map, int player_x, int player_y, int max_radius, bool light_walls) {
int oct,c,r2;
map_t *m = (map_t *)map;
/* clean the map */
for (c=m->nbcells-1; c >= 0; c--) {
m->cells[c].fov=0;
}
if ( max_radius == 0 ) {
int max_radius_x=m->width-player_x;
int max_radius_y=m->height-player_y;
max_radius_x=MAX(max_radius_x,player_x);
max_radius_y=MAX(max_radius_y,player_y);
max_radius = (int)(sqrt(max_radius_x*max_radius_x+max_radius_y*max_radius_y))+1;
}
r2=max_radius*max_radius;
/* recursive shadow casting */
for (oct=0; oct < 8; oct++) cast_light(m,player_x,player_y,1,1.0,0.0,max_radius,r2,
mult[0][oct],mult[1][oct],mult[2][oct],mult[3][oct],0,light_walls);
m->cells[player_x+player_y*m->width].fov=1;
}
