godot/core/math/bvh_abb.h
2022-09-19 15:08:50 -05:00

293 lines
8.1 KiB
C++

/*************************************************************************/
/* bvh_abb.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md). */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/*************************************************************************/
#ifndef BVH_ABB_H
#define BVH_ABB_H
// special optimized version of axis aligned bounding box
template <class BOUNDS = AABB, class POINT = Vector3>
struct BVH_ABB {
struct ConvexHull {
// convex hulls (optional)
const Plane *planes;
int num_planes;
const Vector3 *points;
int num_points;
};
struct Segment {
POINT from;
POINT to;
};
enum IntersectResult {
IR_MISS = 0,
IR_PARTIAL,
IR_FULL,
};
// we store mins with a negative value in order to test them with SIMD
POINT min;
POINT neg_max;
bool operator==(const BVH_ABB &o) const { return (min == o.min) && (neg_max == o.neg_max); }
bool operator!=(const BVH_ABB &o) const { return (*this == o) == false; }
void set(const POINT &_min, const POINT &_max) {
min = _min;
neg_max = -_max;
}
// to and from standard AABB
void from(const BOUNDS &p_aabb) {
min = p_aabb.position;
neg_max = -(p_aabb.position + p_aabb.size);
}
void to(BOUNDS &r_aabb) const {
r_aabb.position = min;
r_aabb.size = calculate_size();
}
void merge(const BVH_ABB &p_o) {
for (int axis = 0; axis < POINT::AXIS_COUNT; ++axis) {
neg_max[axis] = MIN(neg_max[axis], p_o.neg_max[axis]);
min[axis] = MIN(min[axis], p_o.min[axis]);
}
}
POINT calculate_size() const {
return -neg_max - min;
}
POINT calculate_centre() const {
return POINT((calculate_size() * 0.5) + min);
}
real_t get_proximity_to(const BVH_ABB &p_b) const {
const POINT d = (min - neg_max) - (p_b.min - p_b.neg_max);
real_t proximity = 0.0;
for (int axis = 0; axis < POINT::AXIS_COUNT; ++axis) {
proximity += Math::abs(d[axis]);
}
return proximity;
}
int select_by_proximity(const BVH_ABB &p_a, const BVH_ABB &p_b) const {
return (get_proximity_to(p_a) < get_proximity_to(p_b) ? 0 : 1);
}
uint32_t find_cutting_planes(const typename BVH_ABB::ConvexHull &p_hull, uint32_t *p_plane_ids) const {
uint32_t count = 0;
for (int n = 0; n < p_hull.num_planes; n++) {
const Plane &p = p_hull.planes[n];
if (intersects_plane(p)) {
p_plane_ids[count++] = n;
}
}
return count;
}
bool intersects_plane(const Plane &p_p) const {
Vector3 size = calculate_size();
Vector3 half_extents = size * 0.5;
Vector3 ofs = min + half_extents;
// forward side of plane?
Vector3 point_offset(
(p_p.normal.x < 0) ? -half_extents.x : half_extents.x,
(p_p.normal.y < 0) ? -half_extents.y : half_extents.y,
(p_p.normal.z < 0) ? -half_extents.z : half_extents.z);
Vector3 point = point_offset + ofs;
if (!p_p.is_point_over(point)) {
return false;
}
point = -point_offset + ofs;
if (p_p.is_point_over(point)) {
return false;
}
return true;
}
bool intersects_convex_optimized(const ConvexHull &p_hull, const uint32_t *p_plane_ids, uint32_t p_num_planes) const {
Vector3 size = calculate_size();
Vector3 half_extents = size * 0.5;
Vector3 ofs = min + half_extents;
for (unsigned int i = 0; i < p_num_planes; i++) {
const Plane &p = p_hull.planes[p_plane_ids[i]];
Vector3 point(
(p.normal.x > 0) ? -half_extents.x : half_extents.x,
(p.normal.y > 0) ? -half_extents.y : half_extents.y,
(p.normal.z > 0) ? -half_extents.z : half_extents.z);
point += ofs;
if (p.is_point_over(point)) {
return false;
}
}
return true;
}
bool intersects_convex_partial(const ConvexHull &p_hull) const {
BOUNDS bb;
to(bb);
return bb.intersects_convex_shape(p_hull.planes, p_hull.num_planes, p_hull.points, p_hull.num_points);
}
IntersectResult intersects_convex(const ConvexHull &p_hull) const {
if (intersects_convex_partial(p_hull)) {
// fully within? very important for tree checks
if (is_within_convex(p_hull)) {
return IR_FULL;
}
return IR_PARTIAL;
}
return IR_MISS;
}
bool is_within_convex(const ConvexHull &p_hull) const {
// use half extents routine
BOUNDS bb;
to(bb);
return bb.inside_convex_shape(p_hull.planes, p_hull.num_planes);
}
bool is_point_within_hull(const ConvexHull &p_hull, const Vector3 &p_pt) const {
for (int n = 0; n < p_hull.num_planes; n++) {
if (p_hull.planes[n].distance_to(p_pt) > 0.0f) {
return false;
}
}
return true;
}
bool intersects_segment(const Segment &p_s) const {
BOUNDS bb;
to(bb);
return bb.intersects_segment(p_s.from, p_s.to);
}
bool intersects_point(const POINT &p_pt) const {
if (_any_lessthan(-p_pt, neg_max)) {
return false;
}
if (_any_lessthan(p_pt, min)) {
return false;
}
return true;
}
// Very hot in profiling, make sure optimized
bool intersects(const BVH_ABB &p_o) const {
if (_any_morethan(p_o.min, -neg_max)) {
return false;
}
if (_any_morethan(min, -p_o.neg_max)) {
return false;
}
return true;
}
// for pre-swizzled tester (this object)
bool intersects_swizzled(const BVH_ABB &p_o) const {
if (_any_lessthan(min, p_o.min)) {
return false;
}
if (_any_lessthan(neg_max, p_o.neg_max)) {
return false;
}
return true;
}
bool is_other_within(const BVH_ABB &p_o) const {
if (_any_lessthan(p_o.neg_max, neg_max)) {
return false;
}
if (_any_lessthan(p_o.min, min)) {
return false;
}
return true;
}
void grow(const POINT &p_change) {
neg_max -= p_change;
min -= p_change;
}
void expand(real_t p_change) {
POINT change;
for (int axis = 0; axis < POINT::AXIS_COUNT; ++axis) {
change[axis] = p_change;
}
grow(change);
}
// Actually surface area metric.
float get_area() const {
POINT d = calculate_size();
return 2.0f * (d.x * d.y + d.y * d.z + d.z * d.x);
}
void set_to_max_opposite_extents() {
for (int axis = 0; axis < POINT::AXIS_COUNT; ++axis) {
neg_max[axis] = FLT_MAX;
}
min = neg_max;
}
bool _any_morethan(const POINT &p_a, const POINT &p_b) const {
for (int axis = 0; axis < POINT::AXIS_COUNT; ++axis) {
if (p_a[axis] > p_b[axis]) {
return true;
}
}
return false;
}
bool _any_lessthan(const POINT &p_a, const POINT &p_b) const {
for (int axis = 0; axis < POINT::AXIS_COUNT; ++axis) {
if (p_a[axis] < p_b[axis]) {
return true;
}
}
return false;
}
};
#endif // BVH_ABB_H