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correct faulty segment-into-plane collision, adds interior point

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rdb 2011-05-07 12:25:39 +00:00
parent 686e7f39e7
commit 1a0bae35b7
1 changed files with 26 additions and 22 deletions
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48
panda/src/collide/collisionPlane.cxx
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@ -277,26 +277,13 @@ test_intersection_from_segment(const CollisionEntry &entry) const {
LPoint3f from_a = segment->get_point_a() * wrt_mat;
LPoint3f from_b = segment->get_point_b() * wrt_mat;
LVector3f from_direction = from_b - from_a;
float t;
if (_plane.dist_to_plane(from_a) < 0.0f) {
// The first point of the line segment is behind the plane, so we
// don't need to test further.
t = 0.0f;
float dist_a = _plane.dist_to_plane(from_a);
float dist_b = _plane.dist_to_plane(from_b);
} else {
if (!_plane.intersects_line(t, from_a, from_direction)) {
// No intersection. The line segment is parallel to the plane.
return NULL;
}
if (t < 0.0f || t > 1.0f) {
// The intersection point is before the start of the segment or
// after the end of the segment. Therefore, the line segment is
// entirely in front of the plane.
return NULL;
}
if (dist_a >= 0.0f && dist_b >= 0.0f)
// Entirely in front of the plane means no intersection.
return NULL;
}
if (collide_cat.is_debug()) {
@ -306,12 +293,29 @@ test_intersection_from_segment(const CollisionEntry &entry) const {
}
PT(CollisionEntry) new_entry = new CollisionEntry(entry);
LPoint3f into_intersection_point = from_a + t * from_direction;
LVector3f normal = (has_effective_normal() && segment->get_respect_effective_normal()) ? get_effective_normal() : get_normal();
new_entry->set_surface_normal(normal);
new_entry->set_surface_point(into_intersection_point);
if (_plane.intersects_line(t, from_a, from_b - from_a)) {
// It intersects the plane.
if (t >= 0.0f && t <= 1.0f) {
// Within the segment! Yay, that means we have a surface point.
new_entry->set_surface_point(from_a + t * from_direction);
}
}
if (dist_a < dist_b) {
// Point A penetrates deeper.
new_entry->set_interior_point(from_a);
} else if (dist_b < dist_a) {
// No, point B does.
new_entry->set_interior_point(from_b);
} else {
// Let's be fair and choose the center of the segment.
new_entry->set_interior_point((from_a * from_b) * 0.5);
}
return new_entry;
}