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Handle dual collisions.

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When the trace collides with something on both sides of a plane, the nearer
collision is required. The code now correctly checks both sides and keeps
the nearer collision.
This commit is contained in:
Bill Currie 2011-11-13 08:48:44 +09:00
parent 0cf5dec5bb
commit a943cdf2c4
1 changed files with 25 additions and 11 deletions
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36
libs/models/trace.c
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@ -103,17 +103,23 @@ calc_impact (trace_t *trace, const vec3_t start, const vec3_t end,
if (t1 < 0) {
frac = (t1 + offset + DIST_EPSILON) / (t1 - t2);
// invert plane paramterers
VectorNegate (plane->normal, trace->plane.normal);
trace->plane.dist = -plane->dist;
} else {
frac = (t1 - offset - DIST_EPSILON) / (t1 - t2);
VectorCopy (plane->normal, trace->plane.normal);
trace->plane.dist = plane->dist;
}
frac = bound (0, frac, 1);
trace->fraction = frac;
VectorSubtract (end, start, dist);
VectorMultAdd (start, frac, dist, trace->endpos);
if (frac < trace->fraction) {
trace->fraction = frac;
VectorSubtract (end, start, dist);
VectorMultAdd (start, frac, dist, trace->endpos);
if (t1 < 0) {
// invert plane paramterers
VectorNegate (plane->normal, trace->plane.normal);
trace->plane.dist = -plane->dist;
} else {
VectorCopy (plane->normal, trace->plane.normal);
trace->plane.dist = plane->dist;
}
}
}
VISIBLE void
@ -160,7 +166,8 @@ MOD_TraceLine (hull_t *hull, int num,
// crossing from an empty leaf to a solid leaf: the trace
// has collided.
calc_impact (trace, start_point, end_point, split_plane);
return;
if (trace->type == tr_point)
return;
}
} else {
seen_empty = true;
@ -172,6 +179,7 @@ MOD_TraceLine (hull_t *hull, int num,
}
// pop up the stack for a back side
// FIXME detect early out from collisions
if (tstack-- == tracestack) {
// we've finished.
return;
@ -208,13 +216,19 @@ MOD_TraceLine (hull_t *hull, int num,
// cross the plane
if (start_dist < offset && end_dist < offset
&& start_dist >= -offset && end_dist >= end_dist) {
if (start_dist == end_dist) {
// avoid division by zero (non-point clip only)
// since we need to check both sides anyway, it doesn't matter
// which side we start with, so long as the fractions are
// correct.
side = 0;
frac[0] = 1;
frac[1] = 0;
} else {
side = start_dist < offset;
// if either start or end have the box straddling the plane, then
// frac will be appropriately clipped to 0 and 1, otherwise, frac
// will be inside that range
side = start_dist < end_dist;
frac[0] = (start_dist + offset) / (start_dist - end_dist);
frac[1] = (start_dist - offset) / (start_dist - end_dist);
frac[0] = bound (0, frac[0], 1);