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Line box intersection code.

This commit is contained in:
Steve 2018-02-02 18:14:50 +00:00
parent 0817b2e600
commit bac35a3bab
1 changed files with 34 additions and 0 deletions
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34
src/util/util.c
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@ -25,6 +25,40 @@ int collision(int x1, int y1, int w1, int h1, int x2, int y2, int w2, int h2)
return (MAX(x1, x2) < MIN(x1 + w1, x2 + w2)) && (MAX(y1, y2) < MIN(y1 + h1, y2 + h2));
}
int lineLineIntersection(int x1, int y1, int x2, int y2, int x3, int y3, int x4, int y4)
{
int d, n1, n2, ua, ub;
d = ((y4 - y3) * (x2 - x1)) - ((x4 - x3) * (y2 - y1));
n1 = ((x4 - x3) * (y1 - y3)) - ((y4 - y3) * (x1 - x3));
n2 = ((x2 - x1) * (y1 - y3)) - ((y2 - y1) * (x1 - x3));
if (d == 0)
{
if ( n1 == 0 && n2 == 0)
{
return 0;
}
return 0;
}
ua = n1 / d;
ub = n2 / d;
return (ua >= 0 && ua <= 1 && ub >= 0 && ub <= 1);
}
int lineRectIntersection(int x1, int y1, int x2, int y2, SDL_Rect *r)
{
return (
lineLineIntersection(x1, y1, x2, y2, r->x, r->y, r->x + r->w, r->y) || /* top */
lineLineIntersection(x1, y1, x2, y2, r->x, r->y + r->h, r->x + r->w, r->y + r->h) || /* bottom */
lineLineIntersection(x1, y1, x2, y2, r->x, r->y, r->x, r->y + r->h) || /* left */
lineLineIntersection(x1, y1, x2, y2, r->x + r->w, r->y, r->x + r->w, r->y + r->h) /* right */
);
}
char *timeToString(long millis, int showHours)
{
static char TIME[MAX_NAME_LENGTH];