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456 lines
12 KiB
C++
456 lines
12 KiB
C++
/*************************************************************************/
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/* quick_hull.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 "quick_hull.h"
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#include "core/templates/rb_map.h"
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uint32_t QuickHull::debug_stop_after = 0xFFFFFFFF;
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Error QuickHull::build(const Vector<Vector3> &p_points, Geometry3D::MeshData &r_mesh) {
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/* CREATE AABB VOLUME */
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AABB aabb;
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for (int i = 0; i < p_points.size(); i++) {
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if (i == 0) {
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aabb.position = p_points[i];
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} else {
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aabb.expand_to(p_points[i]);
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}
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}
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if (aabb.size == Vector3()) {
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return ERR_CANT_CREATE;
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}
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Vector<bool> valid_points;
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valid_points.resize(p_points.size());
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HashSet<Vector3> valid_cache;
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for (int i = 0; i < p_points.size(); i++) {
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Vector3 sp = p_points[i].snapped(Vector3(0.0001, 0.0001, 0.0001));
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if (valid_cache.has(sp)) {
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valid_points.write[i] = false;
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} else {
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valid_points.write[i] = true;
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valid_cache.insert(sp);
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}
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}
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/* CREATE INITIAL SIMPLEX */
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int longest_axis = aabb.get_longest_axis_index();
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//first two vertices are the most distant
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int simplex[4] = { 0 };
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{
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real_t max = 0, min = 0;
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for (int i = 0; i < p_points.size(); i++) {
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if (!valid_points[i]) {
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continue;
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}
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real_t d = p_points[i][longest_axis];
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if (i == 0 || d < min) {
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simplex[0] = i;
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min = d;
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}
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if (i == 0 || d > max) {
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simplex[1] = i;
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max = d;
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}
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}
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}
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//third vertex is one most further away from the line
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{
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real_t maxd = 0;
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Vector3 rel12 = p_points[simplex[0]] - p_points[simplex[1]];
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for (int i = 0; i < p_points.size(); i++) {
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if (!valid_points[i]) {
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continue;
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}
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Vector3 n = rel12.cross(p_points[simplex[0]] - p_points[i]).cross(rel12).normalized();
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real_t d = Math::abs(n.dot(p_points[simplex[0]]) - n.dot(p_points[i]));
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if (i == 0 || d > maxd) {
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maxd = d;
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simplex[2] = i;
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}
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}
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}
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//fourth vertex is the one most further away from the plane
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{
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real_t maxd = 0;
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Plane p(p_points[simplex[0]], p_points[simplex[1]], p_points[simplex[2]]);
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for (int i = 0; i < p_points.size(); i++) {
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if (!valid_points[i]) {
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continue;
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}
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real_t d = Math::abs(p.distance_to(p_points[i]));
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if (i == 0 || d > maxd) {
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maxd = d;
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simplex[3] = i;
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}
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}
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}
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//compute center of simplex, this is a point always warranted to be inside
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Vector3 center;
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for (int i = 0; i < 4; i++) {
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center += p_points[simplex[i]];
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}
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center /= 4.0;
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//add faces
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List<Face> faces;
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for (int i = 0; i < 4; i++) {
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static const int face_order[4][3] = {
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{ 0, 1, 2 },
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{ 0, 1, 3 },
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{ 0, 2, 3 },
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{ 1, 2, 3 }
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};
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Face f;
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for (int j = 0; j < 3; j++) {
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f.vertices[j] = simplex[face_order[i][j]];
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}
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Plane p(p_points[f.vertices[0]], p_points[f.vertices[1]], p_points[f.vertices[2]]);
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if (p.is_point_over(center)) {
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//flip face to clockwise if facing inwards
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SWAP(f.vertices[0], f.vertices[1]);
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p = -p;
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}
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f.plane = p;
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faces.push_back(f);
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}
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real_t over_tolerance = 3 * UNIT_EPSILON * (aabb.size.x + aabb.size.y + aabb.size.z);
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/* COMPUTE AVAILABLE VERTICES */
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for (int i = 0; i < p_points.size(); i++) {
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if (i == simplex[0]) {
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continue;
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}
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if (i == simplex[1]) {
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continue;
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}
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if (i == simplex[2]) {
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continue;
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}
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if (i == simplex[3]) {
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continue;
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}
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if (!valid_points[i]) {
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continue;
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}
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for (Face &E : faces) {
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if (E.plane.distance_to(p_points[i]) > over_tolerance) {
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E.points_over.push_back(i);
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break;
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}
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}
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}
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faces.sort(); // sort them, so the ones with points are in the back
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/* BUILD HULL */
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//poop face (while still remain)
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//find further away point
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//find lit faces
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//determine horizon edges
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//build new faces with horizon edges, them assign points side from all lit faces
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//remove lit faces
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uint32_t debug_stop = debug_stop_after;
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while (debug_stop > 0 && faces.back()->get().points_over.size()) {
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debug_stop--;
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Face &f = faces.back()->get();
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//find vertex most outside
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int next = -1;
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real_t next_d = 0;
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for (int i = 0; i < f.points_over.size(); i++) {
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real_t d = f.plane.distance_to(p_points[f.points_over[i]]);
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if (d > next_d) {
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next_d = d;
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next = i;
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}
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}
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ERR_FAIL_COND_V(next == -1, ERR_BUG);
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Vector3 v = p_points[f.points_over[next]];
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//find lit faces and lit edges
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List<List<Face>::Element *> lit_faces; //lit face is a death sentence
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HashMap<Edge, FaceConnect, Edge> lit_edges; //create this on the flight, should not be that bad for performance and simplifies code a lot
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for (List<Face>::Element *E = faces.front(); E; E = E->next()) {
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if (E->get().plane.distance_to(v) > 0) {
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lit_faces.push_back(E);
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for (int i = 0; i < 3; i++) {
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uint32_t a = E->get().vertices[i];
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uint32_t b = E->get().vertices[(i + 1) % 3];
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Edge e(a, b);
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HashMap<Edge, FaceConnect, Edge>::Iterator F = lit_edges.find(e);
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if (!F) {
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F = lit_edges.insert(e, FaceConnect());
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}
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if (e.vertices[0] == a) {
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//left
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F->value.left = E;
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} else {
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F->value.right = E;
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}
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}
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}
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}
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//create new faces from horizon edges
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List<List<Face>::Element *> new_faces; //new faces
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for (KeyValue<Edge, FaceConnect> &E : lit_edges) {
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FaceConnect &fc = E.value;
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if (fc.left && fc.right) {
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continue; //edge is uninteresting, not on horizon
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}
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//create new face!
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Face face;
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face.vertices[0] = f.points_over[next];
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face.vertices[1] = E.key.vertices[0];
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face.vertices[2] = E.key.vertices[1];
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Plane p(p_points[face.vertices[0]], p_points[face.vertices[1]], p_points[face.vertices[2]]);
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if (p.is_point_over(center)) {
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//flip face to clockwise if facing inwards
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SWAP(face.vertices[0], face.vertices[1]);
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p = -p;
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}
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face.plane = p;
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new_faces.push_back(faces.push_back(face));
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}
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//distribute points into new faces
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for (List<Face>::Element *&F : lit_faces) {
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Face &lf = F->get();
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for (int i = 0; i < lf.points_over.size(); i++) {
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if (lf.points_over[i] == f.points_over[next]) { //do not add current one
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continue;
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}
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Vector3 p = p_points[lf.points_over[i]];
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for (List<Face>::Element *&E : new_faces) {
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Face &f2 = E->get();
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if (f2.plane.distance_to(p) > over_tolerance) {
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f2.points_over.push_back(lf.points_over[i]);
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break;
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}
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}
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}
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}
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//erase lit faces
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while (lit_faces.size()) {
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faces.erase(lit_faces.front()->get());
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lit_faces.pop_front();
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}
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//put faces that contain no points on the front
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for (List<Face>::Element *&E : new_faces) {
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Face &f2 = E->get();
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if (f2.points_over.size() == 0) {
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faces.move_to_front(E);
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}
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}
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//whew, done with iteration, go next
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}
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/* CREATE MESHDATA */
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//make a map of edges again
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HashMap<Edge, RetFaceConnect, Edge> ret_edges;
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List<Geometry3D::MeshData::Face> ret_faces;
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for (const Face &E : faces) {
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Geometry3D::MeshData::Face f;
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f.plane = E.plane;
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for (int i = 0; i < 3; i++) {
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f.indices.push_back(E.vertices[i]);
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}
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List<Geometry3D::MeshData::Face>::Element *F = ret_faces.push_back(f);
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for (int i = 0; i < 3; i++) {
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uint32_t a = E.vertices[i];
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uint32_t b = E.vertices[(i + 1) % 3];
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Edge e(a, b);
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HashMap<Edge, RetFaceConnect, Edge>::Iterator G = ret_edges.find(e);
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if (!G) {
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G = ret_edges.insert(e, RetFaceConnect());
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}
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if (e.vertices[0] == a) {
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//left
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G->value.left = F;
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} else {
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G->value.right = F;
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}
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}
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}
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//fill faces
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for (List<Geometry3D::MeshData::Face>::Element *E = ret_faces.front(); E; E = E->next()) {
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Geometry3D::MeshData::Face &f = E->get();
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for (int i = 0; i < f.indices.size(); i++) {
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int a = E->get().indices[i];
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int b = E->get().indices[(i + 1) % f.indices.size()];
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Edge e(a, b);
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HashMap<Edge, RetFaceConnect, Edge>::Iterator F = ret_edges.find(e);
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ERR_CONTINUE(!F);
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List<Geometry3D::MeshData::Face>::Element *O = F->value.left == E ? F->value.right : F->value.left;
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ERR_CONTINUE(O == E);
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ERR_CONTINUE(O == nullptr);
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if (O->get().plane.is_equal_approx(f.plane)) {
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//merge and delete edge and contiguous face, while repointing edges (uuugh!)
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int ois = O->get().indices.size();
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for (int j = 0; j < ois; j++) {
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//search a
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if (O->get().indices[j] == a) {
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//append the rest
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for (int k = 0; k < ois; k++) {
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int idx = O->get().indices[(k + j) % ois];
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int idxn = O->get().indices[(k + j + 1) % ois];
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if (idx == b && idxn == a) { //already have b!
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break;
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}
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if (idx != a) {
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f.indices.insert(i + 1, idx);
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i++;
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}
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Edge e2(idx, idxn);
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HashMap<Edge, RetFaceConnect, Edge>::Iterator F2 = ret_edges.find(e2);
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ERR_CONTINUE(!F2);
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//change faceconnect, point to this face instead
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if (F2->value.left == O) {
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F2->value.left = E;
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} else if (F2->value.right == O) {
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F2->value.right = E;
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}
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}
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break;
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}
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}
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// remove all edge connections to this face
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for (KeyValue<Edge, RetFaceConnect> &G : ret_edges) {
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if (G.value.left == O) {
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G.value.left = nullptr;
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}
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if (G.value.right == O) {
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G.value.right = nullptr;
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}
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}
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ret_edges.remove(F); //remove the edge
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ret_faces.erase(O); //remove the face
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}
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}
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}
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//fill mesh
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r_mesh.faces.clear();
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r_mesh.faces.resize(ret_faces.size());
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int idx = 0;
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for (const Geometry3D::MeshData::Face &E : ret_faces) {
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r_mesh.faces.write[idx++] = E;
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}
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r_mesh.edges.resize(ret_edges.size());
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idx = 0;
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for (const KeyValue<Edge, RetFaceConnect> &E : ret_edges) {
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Geometry3D::MeshData::Edge e;
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e.a = E.key.vertices[0];
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e.b = E.key.vertices[1];
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r_mesh.edges.write[idx++] = e;
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}
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r_mesh.vertices = p_points;
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return OK;
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}
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