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(line_of_sight): Normalize coordinates before indexing. Closes

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#950514.

(line_of_sight): There's just one straight line between two points on
a plane, but on a torus there are four.  Code assumed plane, and thus
could screw up near the origin.  Pick a shortest line of the four.
Partial fix for #950510.
This commit is contained in:
Markus Armbruster 2004-05-09 15:54:00 +00:00
parent e4d1c38c96
commit c6678f3899
1 changed files with 8 additions and 5 deletions
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13
src/lib/commands/sona.c
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@ -332,10 +332,12 @@ plane_sona(struct emp_qelem *plane_list, int x, int y,
#define DIST(ax,ay,bx,by) LEN(bx - ax, by -ay)
int
line_of_sight(s_char **rad, int ax, int ay, int bx, int by)
line_of_sight(char **rad, int ax, int ay, int bx, int by)
{
int dx = bx - ax;
int dy = by - ay;
int dxn = XNORM(bx - ax);
int dyn = YNORM(by - ay);
int dx = dxn > WORLD_X / 2 ? dxn - WORLD_X : dxn;
int dy = dyn > WORLD_Y / 2 ? dyn - WORLD_Y : dyn;
int dlen = LEN(dx, dy);
int n;
int cx = 0;
@ -366,12 +368,13 @@ line_of_sight(s_char **rad, int ax, int ay, int bx, int by)
closest = n;
}
}
if (closest < 0) /* not possible */
if (CANT_HAPPEN(closest < 0))
return 0;
cx = cx + diroff[closest][0];
cy = cy + diroff[closest][1];
if (rad) {
blocked = (rad[ay + cy][ax + cx] != dchr[SCT_WATER].d_mnem);
blocked = (rad[YNORM(ay + cy)][XNORM(ax + cx)]
!= dchr[SCT_WATER].d_mnem);
} else {
sectp = getsectp((ax + cx), (ay + cy));
if (sectp) {