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Exact Boolean: speed up when there are many separate components. 

Use bounding box tests quickly tell that two components cannot
have a containment relation between each other. This change
cut about 0.6s off a test with 25 big icospheres.
This commit is contained in:
Howard Trickey 2021-06-05 11:31:08 -07:00
parent edaaa2afdd
commit 8e43ef5f31
3 changed files with 127 additions and 63 deletions
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58
source/blender/blenlib/BLI_mesh_intersect.hh
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@ -29,6 +29,7 @@
# include "BLI_array.hh"
# include "BLI_double3.hh"
# include "BLI_float3.hh"
# include "BLI_index_range.hh"
# include "BLI_map.hh"
# include "BLI_math_mpq.hh"
@ -339,6 +340,63 @@ class IMesh {
std::ostream &operator<<(std::ostream &os, const IMesh &mesh);
/**
* A Bounding Box using floats, and a routine to detect possible
* intersection.
*/
struct BoundingBox {
float3 min{FLT_MAX, FLT_MAX, FLT_MAX};
float3 max{-FLT_MAX, -FLT_MAX, -FLT_MAX};
BoundingBox() = default;
BoundingBox(const float3 &min, const float3 &max) : min(min), max(max)
{
}
void combine(const float3 &p)
{
min.x = min_ff(min.x, p.x);
min.y = min_ff(min.y, p.y);
min.z = min_ff(min.z, p.z);
max.x = max_ff(max.x, p.x);
max.y = max_ff(max.y, p.y);
max.z = max_ff(max.z, p.z);
}
void combine(const double3 &p)
{
min.x = min_ff(min.x, static_cast<float>(p.x));
min.y = min_ff(min.y, static_cast<float>(p.y));
min.z = min_ff(min.z, static_cast<float>(p.z));
max.x = max_ff(max.x, static_cast<float>(p.x));
max.y = max_ff(max.y, static_cast<float>(p.y));
max.z = max_ff(max.z, static_cast<float>(p.z));
}
void combine(const BoundingBox &bb)
{
min.x = min_ff(min.x, bb.min.x);
min.y = min_ff(min.y, bb.min.y);
min.z = min_ff(min.z, bb.min.z);
max.x = max_ff(max.x, bb.max.x);
max.y = max_ff(max.y, bb.max.y);
max.z = max_ff(max.z, bb.max.z);
}
void expand(float pad)
{
min.x -= pad;
min.y -= pad;
min.z -= pad;
max.x += pad;
max.y += pad;
max.z += pad;
}
};
/** Assume bounding boxes have been expanded by a sufficient epsilon. */
bool bbs_might_intersect(const BoundingBox &bb_a, const BoundingBox &bb_b);
/**
* The output will have duplicate vertices merged and degenerate triangles ignored.
* If the input has overlapping co-planar triangles, then there will be

80
source/blender/blenlib/intern/mesh_boolean.cc
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@ -1863,6 +1863,7 @@ static Vector<ComponentContainer> find_component_containers(int comp,
const IMesh &tm,
const PatchesInfo &pinfo,
const TriMeshTopology &tmtopo,
Array<BoundingBox> comp_bb,
IMeshArena *arena)
{
constexpr int dbg_level = 0;
@ -1888,6 +1889,12 @@ static Vector<ComponentContainer> find_component_containers(int comp,
if (dbg_level > 0) {
std::cout << "comp_other = " << comp_other << "\n";
}
if (!bbs_might_intersect(comp_bb[comp], comp_bb[comp_other])) {
if (dbg_level > 0) {
std::cout << "bounding boxes don't overlap\n";
}
continue;
}
int nearest_tri = NO_INDEX;
int nearest_tri_close_vert = -1;
int nearest_tri_close_edge = -1;
@ -1961,6 +1968,51 @@ static Vector<ComponentContainer> find_component_containers(int comp,
return ans;
}
/**
* Populate the per-component bounding boxes, expanding them
* by an appropriate epsilon so that we conservatively will say
* that components could intersect if the BBs overlap.
*/
static void populate_comp_bbs(const Vector<Vector<int>> &components,
const PatchesInfo &pinfo,
const IMesh &im,
Array<BoundingBox> &comp_bb)
{
const int comp_grainsize = 16;
/* To get a good expansion epsilon, we need to find the maximum
* absolute value of any coordinate. Do it first per component,
* then get the overall max. */
Array<double> max_abs(components.size(), 0.0);
parallel_for(components.index_range(), comp_grainsize, [&](IndexRange comp_range) {
for (int c : comp_range) {
BoundingBox &bb = comp_bb[c];
double &maxa = max_abs[c];
for (int p : components[c]) {
const Patch &patch = pinfo.patch(p);
for (int t : patch.tris()) {
const Face &tri = *im.face(t);
for (const Vert *v : tri) {
bb.combine(v->co);
for (int i = 0; i < 3; ++i) {
maxa = max_dd(maxa, fabs(v->co[i]));
}
}
}
}
}
});
double all_max_abs = 0.0;
for (int c : components.index_range()) {
all_max_abs = max_dd(all_max_abs, max_abs[c]);
}
constexpr float pad_factor = 10.0f;
float pad = all_max_abs == 0.0 ? FLT_EPSILON : 2 * FLT_EPSILON * all_max_abs;
pad *= pad_factor;
for (int c : components.index_range()) {
comp_bb[c].expand(pad);
}
}
/**
* The cells and patches are supposed to form a bipartite graph.
* The graph may be disconnected (if parts of meshes are nested or side-by-side
@ -2003,19 +2055,23 @@ static void finish_patch_cell_graph(const IMesh &tm,
}
int tot_components = components.size();
Array<Vector<ComponentContainer>> comp_cont(tot_components);
for (int comp : components.index_range()) {
comp_cont[comp] = find_component_containers(
comp, components, ambient_cell, tm, pinfo, tmtopo, arena);
}
if (dbg_level > 0) {
std::cout << "component containers:\n";
for (int comp : comp_cont.index_range()) {
std::cout << comp << ": ";
for (const ComponentContainer &cc : comp_cont[comp]) {
std::cout << "[containing_comp=" << cc.containing_component
<< ", nearest_cell=" << cc.nearest_cell << ", d2=" << cc.dist_to_cell << "] ";
if (tot_components > 1) {
Array<BoundingBox> comp_bb(tot_components);
populate_comp_bbs(components, pinfo, tm, comp_bb);
for (int comp : components.index_range()) {
comp_cont[comp] = find_component_containers(
comp, components, ambient_cell, tm, pinfo, tmtopo, comp_bb, arena);
}
if (dbg_level > 0) {
std::cout << "component containers:\n";
for (int comp : comp_cont.index_range()) {
std::cout << comp << ": ";
for (const ComponentContainer &cc : comp_cont[comp]) {
std::cout << "[containing_comp=" << cc.containing_component
<< ", nearest_cell=" << cc.nearest_cell << ", d2=" << cc.dist_to_cell << "] ";
}
std::cout << "\n";
}
std::cout << "\n";
}
}
if (dbg_level > 1) {

52
source/blender/blenlib/intern/mesh_intersect.cc
View File

@ -744,62 +744,12 @@ std::ostream &operator<<(std::ostream &os, const IMesh &mesh)
return os;
}
struct BoundingBox {
float3 min{FLT_MAX, FLT_MAX, FLT_MAX};
float3 max{-FLT_MAX, -FLT_MAX, -FLT_MAX};
BoundingBox() = default;
BoundingBox(const float3 &min, const float3 &max) : min(min), max(max)
{
}
void combine(const float3 &p)
{
min.x = min_ff(min.x, p.x);
min.y = min_ff(min.y, p.y);
min.z = min_ff(min.z, p.z);
max.x = max_ff(max.x, p.x);
max.y = max_ff(max.y, p.y);
max.z = max_ff(max.z, p.z);
}
void combine(const double3 &p)
{
min.x = min_ff(min.x, static_cast<float>(p.x));
min.y = min_ff(min.y, static_cast<float>(p.y));
min.z = min_ff(min.z, static_cast<float>(p.z));
max.x = max_ff(max.x, static_cast<float>(p.x));
max.y = max_ff(max.y, static_cast<float>(p.y));
max.z = max_ff(max.z, static_cast<float>(p.z));
}
void combine(const BoundingBox &bb)
{
min.x = min_ff(min.x, bb.min.x);
min.y = min_ff(min.y, bb.min.y);
min.z = min_ff(min.z, bb.min.z);
max.x = max_ff(max.x, bb.max.x);
max.y = max_ff(max.y, bb.max.y);
max.z = max_ff(max.z, bb.max.z);
}
void expand(float pad)
{
min.x -= pad;
min.y -= pad;
min.z -= pad;
max.x += pad;
max.y += pad;
max.z += pad;
}
};
/**
* Assume bounding boxes have been expanded by a sufficient epsilon on all sides
* so that the comparisons against the bb bounds are sufficient to guarantee that
* if an overlap or even touching could happen, this will return true.
*/
static bool bbs_might_intersect(const BoundingBox &bb_a, const BoundingBox &bb_b)
bool bbs_might_intersect(const BoundingBox &bb_a, const BoundingBox &bb_b)
{
return isect_aabb_aabb_v3(bb_a.min, bb_a.max, bb_b.min, bb_b.max);
}