godot/core/math/bsp_tree.cpp
Rémi Verschelde d8223ffa75 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!

(cherry picked from commit c7bc44d5ad)
2017-01-12 19:15:30 +01:00

629 lines
13 KiB
C++

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