252 lines
7.6 KiB
C++
252 lines
7.6 KiB
C++
/*************************************************************************/
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/* bvh_abb.h */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md). */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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#ifndef BVH_ABB_H
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#define BVH_ABB_H
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// special optimized version of axis aligned bounding box
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struct BVH_ABB {
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struct ConvexHull {
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// convex hulls (optional)
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const Plane *planes;
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int num_planes;
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const Vector3 *points;
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int num_points;
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};
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struct Segment {
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Vector3 from;
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Vector3 to;
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};
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enum IntersectResult {
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IR_MISS = 0,
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IR_PARTIAL,
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IR_FULL,
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};
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// we store mins with a negative value in order to test them with SIMD
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Vector3 min;
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Vector3 neg_max;
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bool operator==(const BVH_ABB &o) const { return (min == o.min) && (neg_max == o.neg_max); }
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bool operator!=(const BVH_ABB &o) const { return (*this == o) == false; }
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void set(const Vector3 &_min, const Vector3 &_max) {
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min = _min;
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neg_max = -_max;
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}
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// to and from standard AABB
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void from(const AABB &p_aabb) {
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min = p_aabb.position;
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neg_max = -(p_aabb.position + p_aabb.size);
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}
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void to(AABB &r_aabb) const {
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r_aabb.position = min;
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r_aabb.size = calculate_size();
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}
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void merge(const BVH_ABB &p_o) {
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neg_max.x = MIN(neg_max.x, p_o.neg_max.x);
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neg_max.y = MIN(neg_max.y, p_o.neg_max.y);
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neg_max.z = MIN(neg_max.z, p_o.neg_max.z);
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min.x = MIN(min.x, p_o.min.x);
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min.y = MIN(min.y, p_o.min.y);
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min.z = MIN(min.z, p_o.min.z);
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}
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Vector3 calculate_size() const {
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return -neg_max - min;
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}
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Vector3 calculate_centre() const {
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return Vector3((calculate_size() * 0.5) + min);
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}
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real_t get_proximity_to(const BVH_ABB &p_b) const {
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const Vector3 d = (min - neg_max) - (p_b.min - p_b.neg_max);
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return (Math::abs(d.x) + Math::abs(d.y) + Math::abs(d.z));
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}
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int select_by_proximity(const BVH_ABB &p_a, const BVH_ABB &p_b) const {
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return (get_proximity_to(p_a) < get_proximity_to(p_b) ? 0 : 1);
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}
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uint32_t find_cutting_planes(const BVH_ABB::ConvexHull &p_hull, uint32_t *p_plane_ids) const {
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uint32_t count = 0;
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for (int n = 0; n < p_hull.num_planes; n++) {
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const Plane &p = p_hull.planes[n];
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if (intersects_plane(p)) {
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p_plane_ids[count++] = n;
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}
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}
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return count;
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}
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bool intersects_plane(const Plane &p_p) const {
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Vector3 size = calculate_size();
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Vector3 half_extents = size * 0.5;
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Vector3 ofs = min + half_extents;
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// forward side of plane?
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Vector3 point_offset(
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(p_p.normal.x < 0) ? -half_extents.x : half_extents.x,
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(p_p.normal.y < 0) ? -half_extents.y : half_extents.y,
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(p_p.normal.z < 0) ? -half_extents.z : half_extents.z);
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Vector3 point = point_offset + ofs;
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if (!p_p.is_point_over(point))
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return false;
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point = -point_offset + ofs;
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if (p_p.is_point_over(point))
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return false;
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return true;
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}
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bool intersects_convex_optimized(const ConvexHull &p_hull, const uint32_t *p_plane_ids, uint32_t p_num_planes) const {
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Vector3 size = calculate_size();
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Vector3 half_extents = size * 0.5;
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Vector3 ofs = min + half_extents;
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for (unsigned int i = 0; i < p_num_planes; i++) {
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const Plane &p = p_hull.planes[p_plane_ids[i]];
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Vector3 point(
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(p.normal.x > 0) ? -half_extents.x : half_extents.x,
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(p.normal.y > 0) ? -half_extents.y : half_extents.y,
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(p.normal.z > 0) ? -half_extents.z : half_extents.z);
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point += ofs;
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if (p.is_point_over(point))
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return false;
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}
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return true;
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}
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bool intersects_convex_partial(const ConvexHull &p_hull) const {
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AABB bb;
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to(bb);
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return bb.intersects_convex_shape(p_hull.planes, p_hull.num_planes, p_hull.points, p_hull.num_points);
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}
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IntersectResult intersects_convex(const ConvexHull &p_hull) const {
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if (intersects_convex_partial(p_hull)) {
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// fully within? very important for tree checks
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if (is_within_convex(p_hull)) {
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return IR_FULL;
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}
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return IR_PARTIAL;
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}
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return IR_MISS;
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}
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bool is_within_convex(const ConvexHull &p_hull) const {
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// use half extents routine
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AABB bb;
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to(bb);
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return bb.inside_convex_shape(p_hull.planes, p_hull.num_planes);
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}
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bool is_point_within_hull(const ConvexHull &p_hull, const Vector3 &p_pt) const {
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for (int n = 0; n < p_hull.num_planes; n++) {
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if (p_hull.planes[n].distance_to(p_pt) > 0.0f)
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return false;
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}
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return true;
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}
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bool intersects_segment(const Segment &p_s) const {
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AABB bb;
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to(bb);
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return bb.intersects_segment(p_s.from, p_s.to);
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}
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bool intersects_point(const Vector3 &p_pt) const {
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if (_vector3_any_lessthan(-p_pt, neg_max)) return false;
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if (_vector3_any_lessthan(p_pt, min)) return false;
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return true;
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}
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bool intersects(const BVH_ABB &p_o) const {
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if (_vector3_any_morethan(p_o.min, -neg_max)) return false;
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if (_vector3_any_morethan(min, -p_o.neg_max)) return false;
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return true;
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}
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bool is_other_within(const BVH_ABB &p_o) const {
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if (_vector3_any_lessthan(p_o.neg_max, neg_max)) return false;
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if (_vector3_any_lessthan(p_o.min, min)) return false;
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return true;
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}
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void grow(const Vector3 &p_change) {
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neg_max -= p_change;
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min -= p_change;
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}
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void expand(real_t p_change) {
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grow(Vector3(p_change, p_change, p_change));
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}
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float get_area() const // actually surface area metric
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{
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Vector3 d = calculate_size();
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return 2.0f * (d.x * d.y + d.y * d.z + d.z * d.x);
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}
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void set_to_max_opposite_extents() {
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neg_max = Vector3(FLT_MAX, FLT_MAX, FLT_MAX);
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min = neg_max;
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}
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bool _vector3_any_morethan(const Vector3 &p_a, const Vector3 &p_b) const {
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if (p_a.x > p_b.x) return true;
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if (p_a.y > p_b.y) return true;
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if (p_a.z > p_b.z) return true;
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return false;
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}
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bool _vector3_any_lessthan(const Vector3 &p_a, const Vector3 &p_b) const {
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if (p_a.x < p_b.x) return true;
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if (p_a.y < p_b.y) return true;
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if (p_a.z < p_b.z) return true;
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return false;
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}
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};
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#endif // BVH_ABB_H
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