553 lines
14 KiB
C++
553 lines
14 KiB
C++
/*************************************************************************/
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/* bsp_tree.cpp */
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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) 2007-2022 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2022 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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#include "bsp_tree.h"
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#include "core/error_macros.h"
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#include "core/print_string.h"
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void BSP_Tree::from_aabb(const AABB &p_aabb) {
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planes.clear();
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for (int i = 0; i < 3; i++) {
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Vector3 n;
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n[i] = 1;
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planes.push_back(Plane(n, p_aabb.position[i] + p_aabb.size[i]));
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planes.push_back(Plane(-n, -p_aabb.position[i]));
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}
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nodes.clear();
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for (int i = 0; i < 6; i++) {
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Node n;
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n.plane = i;
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n.under = (i == 0) ? UNDER_LEAF : i - 1;
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n.over = OVER_LEAF;
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nodes.push_back(n);
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}
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aabb = p_aabb;
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error_radius = 0;
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}
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Vector<BSP_Tree::Node> BSP_Tree::get_nodes() const {
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return nodes;
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}
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Vector<Plane> BSP_Tree::get_planes() const {
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return planes;
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}
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AABB BSP_Tree::get_aabb() const {
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return aabb;
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}
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int BSP_Tree::_get_points_inside(int p_node, const Vector3 *p_points, int *p_indices, const Vector3 &p_center, const Vector3 &p_half_extents, int p_indices_count) const {
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const Node *node = &nodes[p_node];
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const Plane &p = planes[node->plane];
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Vector3 min(
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(p.normal.x > 0) ? -p_half_extents.x : p_half_extents.x,
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(p.normal.y > 0) ? -p_half_extents.y : p_half_extents.y,
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(p.normal.z > 0) ? -p_half_extents.z : p_half_extents.z);
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Vector3 max = -min;
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max += p_center;
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min += p_center;
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real_t dist_min = p.distance_to(min);
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real_t dist_max = p.distance_to(max);
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if ((dist_min * dist_max) < CMP_EPSILON) { //intersection, test point by point
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int under_count = 0;
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//sort points, so the are under first, over last
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for (int i = 0; i < p_indices_count; i++) {
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int index = p_indices[i];
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if (p.is_point_over(p_points[index])) {
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// kind of slow (but cache friendly), should try something else,
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// but this is a corner case most of the time
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for (int j = index; j < p_indices_count - 1; j++) {
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p_indices[j] = p_indices[j + 1];
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}
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p_indices[p_indices_count - 1] = index;
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} else {
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under_count++;
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}
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}
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int total = 0;
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if (under_count > 0) {
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if (node->under == UNDER_LEAF) {
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total += under_count;
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} else {
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total += _get_points_inside(node->under, p_points, p_indices, p_center, p_half_extents, under_count);
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}
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}
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if (under_count != p_indices_count) {
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if (node->over == OVER_LEAF) {
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//total+=0 //if they are over an OVER_LEAF, they are outside the model
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} else {
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total += _get_points_inside(node->over, p_points, &p_indices[under_count], p_center, p_half_extents, p_indices_count - under_count);
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}
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}
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return total;
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} else if (dist_min > 0) { //all points over plane
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if (node->over == OVER_LEAF) {
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return 0; // all these points are not visible
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}
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return _get_points_inside(node->over, p_points, p_indices, p_center, p_half_extents, p_indices_count);
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} else { //all points behind plane
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if (node->under == UNDER_LEAF) {
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return p_indices_count; // all these points are visible
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}
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return _get_points_inside(node->under, p_points, p_indices, p_center, p_half_extents, p_indices_count);
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}
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}
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int BSP_Tree::get_points_inside(const Vector3 *p_points, int p_point_count) const {
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if (nodes.size() == 0) {
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return 0;
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}
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#if 1
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//this version is easier to debug, and and MUCH faster in real world cases
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int pass_count = 0;
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const Node *nodesptr = &nodes[0];
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const Plane *planesptr = &planes[0];
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int node_count = nodes.size();
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if (node_count == 0) { // no nodes!
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return 0;
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}
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for (int i = 0; i < p_point_count; i++) {
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const Vector3 &point = p_points[i];
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if (!aabb.has_point(point)) {
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continue;
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}
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int idx = node_count - 1;
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bool pass = false;
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while (true) {
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if (idx == OVER_LEAF) {
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pass = false;
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break;
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} else if (idx == UNDER_LEAF) {
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pass = true;
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break;
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}
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#ifdef DEBUG_ENABLED
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int plane_count = planes.size();
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uint16_t plane = nodesptr[idx].plane;
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ERR_FAIL_UNSIGNED_INDEX_V(plane, plane_count, 0);
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#endif
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idx = planesptr[nodesptr[idx].plane].is_point_over(point) ? nodes[idx].over : nodes[idx].under;
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#ifdef DEBUG_ENABLED
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ERR_FAIL_COND_V(idx < MAX_NODES && idx >= node_count, 0);
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#endif
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}
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if (pass) {
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pass_count++;
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}
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}
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return pass_count;
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#else
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//this version scales better but it's slower for real world cases
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int *indices = (int *)alloca(p_point_count * sizeof(int));
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AABB bounds;
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for (int i = 0; i < p_point_count; i++) {
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indices[i] = i;
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if (i == 0)
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bounds.pos = p_points[i];
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else
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bounds.expand_to(p_points[i]);
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}
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Vector3 half_extents = bounds.size / 2.0;
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return _get_points_inside(nodes.size() + 1, p_points, indices, bounds.pos + half_extents, half_extents, p_point_count);
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#endif
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}
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bool BSP_Tree::point_is_inside(const Vector3 &p_point) const {
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if (!aabb.has_point(p_point)) {
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return false;
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}
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int node_count = nodes.size();
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if (node_count == 0) { // no nodes!
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return false;
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}
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const Node *nodesptr = &nodes[0];
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const Plane *planesptr = &planes[0];
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int idx = node_count - 1;
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while (true) {
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if (idx == OVER_LEAF) {
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return false;
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}
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if (idx == UNDER_LEAF) {
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return true;
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}
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#ifdef DEBUG_ENABLED
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int plane_count = planes.size();
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uint16_t plane = nodesptr[idx].plane;
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ERR_FAIL_UNSIGNED_INDEX_V(plane, plane_count, false);
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#endif
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bool over = planesptr[nodesptr[idx].plane].is_point_over(p_point);
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idx = over ? nodes[idx].over : nodes[idx].under;
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#ifdef DEBUG_ENABLED
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ERR_FAIL_COND_V(idx < MAX_NODES && idx >= node_count, false);
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#endif
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}
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}
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static int _bsp_find_best_half_plane(const Face3 *p_faces, const Vector<int> &p_indices, real_t p_tolerance) {
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int ic = p_indices.size();
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const int *indices = p_indices.ptr();
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int best_plane = -1;
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real_t best_plane_cost = 1e20;
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// Loop to find the polygon that best divides the set.
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for (int i = 0; i < ic; i++) {
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const Face3 &f = p_faces[indices[i]];
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Plane p = f.get_plane();
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int num_over = 0, num_under = 0, num_spanning = 0;
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for (int j = 0; j < ic; j++) {
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if (i == j) {
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continue;
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}
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const Face3 &g = p_faces[indices[j]];
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int over = 0, under = 0;
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for (int k = 0; k < 3; k++) {
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real_t d = p.distance_to(g.vertex[j]);
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if (Math::abs(d) > p_tolerance) {
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if (d > 0) {
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over++;
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} else {
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under++;
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}
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}
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}
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if (over && under) {
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num_spanning++;
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} else if (over) {
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num_over++;
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} else {
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num_under++;
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}
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}
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//real_t split_cost = num_spanning / (real_t) face_count;
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real_t relation = Math::abs(num_over - num_under) / (real_t)ic;
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// being honest, i never found a way to add split cost to the mix in a meaninguful way
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// in this engine, also, will likely be ignored anyway
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real_t plane_cost = /*split_cost +*/ relation;
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//printf("plane %i, %i over, %i under, %i spanning, cost is %g\n",i,num_over,num_under,num_spanning,plane_cost);
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if (plane_cost < best_plane_cost) {
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best_plane = i;
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best_plane_cost = plane_cost;
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}
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}
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return best_plane;
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}
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static int _bsp_create_node(const Face3 *p_faces, const Vector<int> &p_indices, Vector<Plane> &p_planes, Vector<BSP_Tree::Node> &p_nodes, real_t p_tolerance) {
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ERR_FAIL_COND_V(p_nodes.size() == BSP_Tree::MAX_NODES, -1);
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// should not reach here
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ERR_FAIL_COND_V(p_indices.size() == 0, -1);
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int ic = p_indices.size();
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const int *indices = p_indices.ptr();
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int divisor_idx = _bsp_find_best_half_plane(p_faces, p_indices, p_tolerance);
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// returned error
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ERR_FAIL_COND_V(divisor_idx < 0, -1);
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Vector<int> faces_over;
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Vector<int> faces_under;
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Plane divisor_plane = p_faces[indices[divisor_idx]].get_plane();
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for (int i = 0; i < ic; i++) {
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if (i == divisor_idx) {
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continue;
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}
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const Face3 &f = p_faces[indices[i]];
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/*
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if (f.get_plane().is_equal_approx(divisor_plane))
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continue;
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*/
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int over_count = 0;
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int under_count = 0;
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for (int j = 0; j < 3; j++) {
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real_t d = divisor_plane.distance_to(f.vertex[j]);
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if (Math::abs(d) > p_tolerance) {
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if (d > 0) {
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over_count++;
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} else {
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under_count++;
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}
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}
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}
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if (over_count) {
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faces_over.push_back(indices[i]);
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}
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if (under_count) {
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faces_under.push_back(indices[i]);
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}
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}
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uint16_t over_idx = BSP_Tree::OVER_LEAF, under_idx = BSP_Tree::UNDER_LEAF;
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if (faces_over.size() > 0) { //have facess above?
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int idx = _bsp_create_node(p_faces, faces_over, p_planes, p_nodes, p_tolerance);
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if (idx >= 0) {
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over_idx = idx;
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}
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}
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if (faces_under.size() > 0) { //have facess above?
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int idx = _bsp_create_node(p_faces, faces_under, p_planes, p_nodes, p_tolerance);
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if (idx >= 0) {
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under_idx = idx;
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}
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}
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/* Create the node */
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// find existing divisor plane
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int divisor_plane_idx = -1;
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for (int i = 0; i < p_planes.size(); i++) {
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if (p_planes[i].is_equal_approx(divisor_plane)) {
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divisor_plane_idx = i;
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break;
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}
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}
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if (divisor_plane_idx == -1) {
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ERR_FAIL_COND_V(p_planes.size() == BSP_Tree::MAX_PLANES, -1);
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divisor_plane_idx = p_planes.size();
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p_planes.push_back(divisor_plane);
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}
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BSP_Tree::Node node;
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node.plane = divisor_plane_idx;
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node.under = under_idx;
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node.over = over_idx;
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p_nodes.push_back(node);
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return p_nodes.size() - 1;
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}
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BSP_Tree::operator Variant() const {
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Dictionary d;
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d["error_radius"] = error_radius;
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Vector<real_t> plane_values;
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plane_values.resize(planes.size() * 4);
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for (int i = 0; i < planes.size(); i++) {
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plane_values.write[i * 4 + 0] = planes[i].normal.x;
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plane_values.write[i * 4 + 1] = planes[i].normal.y;
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plane_values.write[i * 4 + 2] = planes[i].normal.z;
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plane_values.write[i * 4 + 3] = planes[i].d;
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}
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d["planes"] = plane_values;
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PoolVector<int> dst_nodes;
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dst_nodes.resize(nodes.size() * 3);
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for (int i = 0; i < nodes.size(); i++) {
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dst_nodes.set(i * 3 + 0, nodes[i].over);
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dst_nodes.set(i * 3 + 1, nodes[i].under);
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dst_nodes.set(i * 3 + 2, nodes[i].plane);
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}
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d["nodes"] = dst_nodes;
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d["aabb"] = aabb;
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return Variant(d);
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}
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BSP_Tree::BSP_Tree() {
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}
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BSP_Tree::BSP_Tree(const Variant &p_variant) {
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Dictionary d = p_variant;
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ERR_FAIL_COND(!d.has("nodes"));
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ERR_FAIL_COND(!d.has("planes"));
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ERR_FAIL_COND(!d.has("aabb"));
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ERR_FAIL_COND(!d.has("error_radius"));
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PoolVector<int> src_nodes = d["nodes"];
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ERR_FAIL_COND(src_nodes.size() % 3);
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if (d["planes"].get_type() == Variant::POOL_REAL_ARRAY) {
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PoolVector<real_t> src_planes = d["planes"];
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int plane_count = src_planes.size();
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ERR_FAIL_COND(plane_count % 4);
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planes.resize(plane_count / 4);
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if (plane_count) {
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PoolVector<real_t>::Read r = src_planes.read();
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for (int i = 0; i < plane_count / 4; i++) {
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planes.write[i].normal.x = r[i * 4 + 0];
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planes.write[i].normal.y = r[i * 4 + 1];
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planes.write[i].normal.z = r[i * 4 + 2];
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planes.write[i].d = r[i * 4 + 3];
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}
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}
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} else {
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planes = d["planes"];
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}
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error_radius = d["error"];
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aabb = d["aabb"];
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//int node_count = src_nodes.size();
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nodes.resize(src_nodes.size() / 3);
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PoolVector<int>::Read r = src_nodes.read();
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for (int i = 0; i < nodes.size(); i++) {
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nodes.write[i].over = r[i * 3 + 0];
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nodes.write[i].under = r[i * 3 + 1];
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nodes.write[i].plane = r[i * 3 + 2];
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}
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}
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BSP_Tree::BSP_Tree(const PoolVector<Face3> &p_faces, real_t p_error_radius) {
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// compute aabb
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int face_count = p_faces.size();
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PoolVector<Face3>::Read faces_r = p_faces.read();
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const Face3 *facesptr = faces_r.ptr();
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bool first = true;
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Vector<int> indices;
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for (int i = 0; i < face_count; i++) {
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const Face3 &f = facesptr[i];
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if (f.is_degenerate()) {
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continue;
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}
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for (int j = 0; j < 3; j++) {
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if (first) {
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aabb.position = f.vertex[0];
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first = false;
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} else {
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aabb.expand_to(f.vertex[j]);
|
|
}
|
|
}
|
|
|
|
indices.push_back(i);
|
|
}
|
|
|
|
ERR_FAIL_COND(aabb.has_no_area());
|
|
|
|
int top = _bsp_create_node(faces_r.ptr(), indices, planes, nodes, aabb.get_longest_axis_size() * 0.0001);
|
|
|
|
if (top < 0) {
|
|
nodes.clear();
|
|
planes.clear();
|
|
ERR_FAIL_COND(top < 0);
|
|
}
|
|
|
|
error_radius = p_error_radius;
|
|
}
|
|
|
|
BSP_Tree::BSP_Tree(const Vector<Node> &p_nodes, const Vector<Plane> &p_planes, const AABB &p_aabb, real_t p_error_radius) :
|
|
nodes(p_nodes),
|
|
planes(p_planes),
|
|
aabb(p_aabb),
|
|
error_radius(p_error_radius) {
|
|
}
|
|
|
|
BSP_Tree::~BSP_Tree() {
|
|
}
|