godot/core/math/quick_hull.cpp
Rémi Verschelde c7bc44d5ad Welcome in 2017, dear changelog reader!
That year should bring the long-awaited OpenGL ES 3.0 compatible renderer
with state-of-the-art rendering techniques tuned to work as low as middle
end handheld devices - without compromising with the possibilities given
for higher end desktop games of course. Great times ahead for the Godot
community and the gamers that will play our games!
2017-01-01 22:03:33 +01:00

515 lines
11 KiB
C++

/*************************************************************************/
/* quick_hull.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* http://www.godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
/* */
/* 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.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#include "quick_hull.h"
#include "map.h"
uint32_t QuickHull::debug_stop_after=0xFFFFFFFF;
Error QuickHull::build(const Vector<Vector3>& p_points, Geometry::MeshData &r_mesh) {
static const real_t over_tolerance = 0.0001;
/* CREATE AABB VOLUME */
AABB aabb;
for(int i=0;i<p_points.size();i++) {
if (i==0) {
aabb.pos=p_points[i];
} else {
aabb.expand_to(p_points[i]);
}
}
if (aabb.size==Vector3()) {
return ERR_CANT_CREATE;
}
Vector<bool> valid_points;
valid_points.resize(p_points.size());
Set<Vector3> valid_cache;
for(int i=0;i<p_points.size();i++) {
Vector3 sp = p_points[i].snapped(0.0001);
if (valid_cache.has(sp)) {
valid_points[i]=false;
//print_line("INVALIDATED: "+itos(i));
}else {
valid_points[i]=true;
valid_cache.insert(sp);
}
}
/* CREATE INITIAL SIMPLEX */
int longest_axis = aabb.get_longest_axis_index();
//first two vertices are the most distant
int simplex[4];
{
real_t max,min;
for(int i=0;i<p_points.size();i++) {
if (!valid_points[i])
continue;
float d = p_points[i][longest_axis];
if (i==0 || d < min) {
simplex[0]=i;
min=d;
}
if (i==0 || d > max) {
simplex[1]=i;
max=d;
}
}
}
//third vertex is one most further away from the line
{
float maxd;
Vector3 rel12 = p_points[simplex[0]] - p_points[simplex[1]];
for(int i=0;i<p_points.size();i++) {
if (!valid_points[i])
continue;
Vector3 n = rel12.cross(p_points[simplex[0]]-p_points[i]).cross(rel12).normalized();
real_t d = Math::abs(n.dot(p_points[simplex[0]])-n.dot(p_points[i]));
if (i==0 || d>maxd) {
maxd=d;
simplex[2]=i;
}
}
}
//fourth vertex is the one most further away from the plane
{
float maxd;
Plane p(p_points[simplex[0]],p_points[simplex[1]],p_points[simplex[2]]);
for(int i=0;i<p_points.size();i++) {
if (!valid_points[i])
continue;
real_t d = Math::abs(p.distance_to(p_points[i]));
if (i==0 || d>maxd) {
maxd=d;
simplex[3]=i;
}
}
}
//compute center of simplex, this is a point always warranted to be inside
Vector3 center;
for(int i=0;i<4;i++) {
center+=p_points[simplex[i]];
}
center/=4.0;
//add faces
List<Face> faces;
for(int i=0;i<4;i++) {
static const int face_order[4][3]={
{0,1,2},
{0,1,3},
{0,2,3},
{1,2,3}
};
Face f;
for(int j=0;j<3;j++) {
f.vertices[j]=simplex[face_order[i][j]];
}
Plane p(p_points[f.vertices[0]],p_points[f.vertices[1]],p_points[f.vertices[2]]);
if (p.is_point_over(center)) {
//flip face to clockwise if facing inwards
SWAP( f.vertices[0], f.vertices[1] );
p=-p;
}
f.plane = p;
faces.push_back(f);
}
/* COMPUTE AVAILABLE VERTICES */
for(int i=0;i<p_points.size();i++) {
if (i==simplex[0])
continue;
if (i==simplex[1])
continue;
if (i==simplex[2])
continue;
if (i==simplex[3])
continue;
if (!valid_points[i])
continue;
for(List<Face>::Element *E=faces.front();E;E=E->next()) {
if (E->get().plane.distance_to(p_points[i]) > over_tolerance ) {
E->get().points_over.push_back(i);
break;
}
}
}
faces.sort(); // sort them, so the ones with points are in the back
/* BUILD HULL */
//poop face (while still remain)
//find further away point
//find lit faces
//determine horizon edges
//build new faces with horizon edges, them assign points side from all lit faces
//remove lit faces
uint32_t debug_stop = debug_stop_after;
while(debug_stop>0 && faces.back()->get().points_over.size()) {
debug_stop--;
Face& f = faces.back()->get();
//find vertex most outside
int next=-1;
real_t next_d=0;
for(int i=0;i<f.points_over.size();i++) {
real_t d = f.plane.distance_to(p_points[f.points_over[i]]);
if (d > next_d) {
next_d=d;
next=i;
}
}
ERR_FAIL_COND_V(next==-1,ERR_BUG);
Vector3 v = p_points[f.points_over[next]];
//find lit faces and lit edges
List< List<Face>::Element* > lit_faces; //lit face is a death sentence
Map<Edge,FaceConnect> lit_edges; //create this on the flight, should not be that bad for performance and simplifies code a lot
for(List<Face>::Element *E=faces.front();E;E=E->next()) {
if (E->get().plane.distance_to(v) >0 ) {
lit_faces.push_back(E);
for(int i=0;i<3;i++) {
uint32_t a = E->get().vertices[i];
uint32_t b = E->get().vertices[(i+1)%3];
Edge e(a,b);
Map<Edge,FaceConnect>::Element *F=lit_edges.find(e);
if (!F) {
F=lit_edges.insert(e,FaceConnect());
}
if (e.vertices[0]==a) {
//left
F->get().left=E;
} else {
F->get().right=E;
}
}
}
}
//create new faces from horizon edges
List< List<Face>::Element* > new_faces; //new faces
for(Map<Edge,FaceConnect>::Element *E=lit_edges.front();E;E=E->next()) {
FaceConnect& fc = E->get();
if (fc.left && fc.right) {
continue; //edge is uninteresting, not on horizont
}
//create new face!
Face face;
face.vertices[0]=f.points_over[next];
face.vertices[1]=E->key().vertices[0];
face.vertices[2]=E->key().vertices[1];
Plane p(p_points[face.vertices[0]],p_points[face.vertices[1]],p_points[face.vertices[2]]);
if (p.is_point_over(center)) {
//flip face to clockwise if facing inwards
SWAP( face.vertices[0], face.vertices[1] );
p = -p;
}
face.plane = p;
new_faces.push_back( faces.push_back(face) );
}
//distribute points into new faces
for(List< List<Face>::Element* >::Element *F=lit_faces.front();F;F=F->next()) {
Face &lf = F->get()->get();
for(int i=0;i<lf.points_over.size();i++) {
if (lf.points_over[i]==f.points_over[next]) //do not add current one
continue;
Vector3 p = p_points[lf.points_over[i]];
for (List< List<Face>::Element* >::Element *E=new_faces.front();E;E=E->next()) {
Face &f2 = E->get()->get();
if (f2.plane.distance_to(p)>over_tolerance) {
f2.points_over.push_back(lf.points_over[i]);
break;
}
}
}
}
//erase lit faces
while(lit_faces.size()) {
faces.erase(lit_faces.front()->get());
lit_faces.pop_front();
}
//put faces that contain no points on the front
for (List< List<Face>::Element* >::Element *E=new_faces.front();E;E=E->next()) {
Face &f2 = E->get()->get();
if (f2.points_over.size()==0) {
faces.move_to_front(E->get());
}
}
//whew, done with iteration, go next
}
/* CREATE MESHDATA */
//make a map of edges again
Map<Edge,RetFaceConnect> ret_edges;
List<Geometry::MeshData::Face> ret_faces;
for(List<Face>::Element *E=faces.front();E;E=E->next()) {
Geometry::MeshData::Face f;
f.plane = E->get().plane;
for(int i=0;i<3;i++) {
f.indices.push_back(E->get().vertices[i]);
}
List<Geometry::MeshData::Face>::Element *F = ret_faces.push_back(f);
for(int i=0;i<3;i++) {
uint32_t a = E->get().vertices[i];
uint32_t b = E->get().vertices[(i+1)%3];
Edge e(a,b);
Map<Edge,RetFaceConnect>::Element *G=ret_edges.find(e);
if (!G) {
G=ret_edges.insert(e,RetFaceConnect());
}
if (e.vertices[0]==a) {
//left
G->get().left=F;
} else {
G->get().right=F;
}
}
}
//fill faces
for (List<Geometry::MeshData::Face>::Element *E=ret_faces.front();E;E=E->next()) {
Geometry::MeshData::Face& f = E->get();
for(int i=0;i<f.indices.size();i++) {
uint32_t a = E->get().indices[i];
uint32_t b = E->get().indices[(i+1)%f.indices.size()];
Edge e(a,b);
Map<Edge,RetFaceConnect>::Element *F=ret_edges.find(e);
ERR_CONTINUE(!F);
List<Geometry::MeshData::Face>::Element *O = F->get().left == E ? F->get().right : F->get().left;
ERR_CONTINUE(O==E);
ERR_CONTINUE(O==NULL);
if (O->get().plane.is_almost_like(f.plane)) {
//merge and delete edge and contiguous face, while repointing edges (uuugh!)
int ois = O->get().indices.size();
int merged=0;
for(int j=0;j<ois;j++) {
//search a
if (O->get().indices[j]==a) {
//append the rest
for(int k=0;k<ois;k++) {
int idx = O->get().indices[(k+j)%ois];
int idxn = O->get().indices[(k+j+1)%ois];
if (idx==b && idxn==a) {//already have b!
break;
}
if (idx!=a) {
f.indices.insert(i+1,idx);
i++;
merged++;
}
Edge e2(idx,idxn);
Map<Edge,RetFaceConnect>::Element *F2=ret_edges.find(e2);
ERR_CONTINUE(!F2);
//change faceconnect, point to this face instead
if (F2->get().left == O)
F2->get().left=E;
else if (F2->get().right == O)
F2->get().right=E;
}
break;
}
}
ret_edges.erase(F); //remove the edge
ret_faces.erase(O); //remove the face
}
}
}
//fill mesh
r_mesh.faces.clear();
r_mesh.faces.resize(ret_faces.size());
// print_line("FACECOUNT: "+itos(r_mesh.faces.size()));
int idx=0;
for (List<Geometry::MeshData::Face>::Element *E=ret_faces.front();E;E=E->next()) {
r_mesh.faces[idx++]=E->get();
}
r_mesh.edges.resize(ret_edges.size());
idx=0;
for(Map<Edge,RetFaceConnect>::Element *E=ret_edges.front();E;E=E->next()) {
Geometry::MeshData::Edge e;
e.a=E->key().vertices[0];
e.b=E->key().vertices[1];
r_mesh.edges[idx++]=e;
}
r_mesh.vertices=p_points;
//r_mesh.optimize_vertices();
/*
print_line("FACES: "+itos(r_mesh.faces.size()));
print_line("EDGES: "+itos(r_mesh.edges.size()));
print_line("VERTICES: "+itos(r_mesh.vertices.size()));
*/
return OK;
}