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virtualx-engine/core/math/triangle_mesh.cpp
Rémi Verschelde d95794ec8a
One Copyright Update to rule them all 
As many open source projects have started doing it, we're removing the
current year from the copyright notice, so that we don't need to bump
it every year.

It seems like only the first year of publication is technically
relevant for copyright notices, and even that seems to be something
that many companies stopped listing altogether (in a version controlled
codebase, the commits are a much better source of date of publication
than a hardcoded copyright statement).

We also now list Godot Engine contributors first as we're collectively
the current maintainers of the project, and we clarify that the
"exclusive" copyright of the co-founders covers the timespan before
opensourcing (their further contributions are included as part of Godot
Engine contributors).

Also fixed "cf." Frenchism - it's meant as "refer to / see".
2023-01-05 13:25:55 +01:00

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/**************************************************************************/
/* triangle_mesh.cpp */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 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 "triangle_mesh.h"
#include "core/templates/sort_array.h"
int TriangleMesh::_create_bvh(BVH *p_bvh, BVH **p_bb, int p_from, int p_size, int p_depth, int &r_max_depth, int &r_max_alloc) {
if (p_depth > r_max_depth) {
r_max_depth = p_depth;
}
if (p_size == 1) {
return p_bb[p_from] - p_bvh;
} else if (p_size == 0) {
return -1;
}
AABB aabb;
aabb = p_bb[p_from]->aabb;
for (int i = 1; i < p_size; i++) {
aabb.merge_with(p_bb[p_from + i]->aabb);
}
int li = aabb.get_longest_axis_index();
switch (li) {
case Vector3::AXIS_X: {
SortArray<BVH *, BVHCmpX> sort_x;
sort_x.nth_element(0, p_size, p_size / 2, &p_bb[p_from]);
//sort_x.sort(&p_bb[p_from],p_size);
} break;
case Vector3::AXIS_Y: {
SortArray<BVH *, BVHCmpY> sort_y;
sort_y.nth_element(0, p_size, p_size / 2, &p_bb[p_from]);
//sort_y.sort(&p_bb[p_from],p_size);
} break;
case Vector3::AXIS_Z: {
SortArray<BVH *, BVHCmpZ> sort_z;
sort_z.nth_element(0, p_size, p_size / 2, &p_bb[p_from]);
//sort_z.sort(&p_bb[p_from],p_size);
} break;
}
int left = _create_bvh(p_bvh, p_bb, p_from, p_size / 2, p_depth + 1, r_max_depth, r_max_alloc);
int right = _create_bvh(p_bvh, p_bb, p_from + p_size / 2, p_size - p_size / 2, p_depth + 1, r_max_depth, r_max_alloc);
int index = r_max_alloc++;
BVH *_new = &p_bvh[index];
_new->aabb = aabb;
_new->center = aabb.get_center();
_new->face_index = -1;
_new->left = left;
_new->right = right;
return index;
}
void TriangleMesh::get_indices(Vector<int> *r_triangles_indices) const {
if (!valid) {
return;
}
const int triangles_num = triangles.size();
// Parse vertices indices
const Triangle *triangles_read = triangles.ptr();
r_triangles_indices->resize(triangles_num * 3);
int *r_indices_write = r_triangles_indices->ptrw();
for (int i = 0; i < triangles_num; ++i) {
r_indices_write[3 * i + 0] = triangles_read[i].indices[0];
r_indices_write[3 * i + 1] = triangles_read[i].indices[1];
r_indices_write[3 * i + 2] = triangles_read[i].indices[2];
}
}
void TriangleMesh::create(const Vector<Vector3> &p_faces, const Vector<int32_t> &p_surface_indices) {
valid = false;
ERR_FAIL_COND(p_surface_indices.size() && p_surface_indices.size() != p_faces.size());
int fc = p_faces.size();
ERR_FAIL_COND(!fc || ((fc % 3) != 0));
fc /= 3;
triangles.resize(fc);
bvh.resize(fc * 3); //will never be larger than this (todo make better)
BVH *bw = bvh.ptrw();
{
//create faces and indices and base bvh
//except for the Set for repeated triangles, everything
//goes in-place.
const Vector3 *r = p_faces.ptr();
const int32_t *si = p_surface_indices.ptr();
Triangle *w = triangles.ptrw();
HashMap<Vector3, int> db;
for (int i = 0; i < fc; i++) {
Triangle &f = w[i];
const Vector3 *v = &r[i * 3];
for (int j = 0; j < 3; j++) {
int vidx = -1;
Vector3 vs = v[j].snapped(Vector3(0.0001, 0.0001, 0.0001));
HashMap<Vector3, int>::Iterator E = db.find(vs);
if (E) {
vidx = E->value;
} else {
vidx = db.size();
db[vs] = vidx;
}
f.indices[j] = vidx;
if (j == 0) {
bw[i].aabb.position = vs;
} else {
bw[i].aabb.expand_to(vs);
}
}
f.normal = Face3(r[i * 3 + 0], r[i * 3 + 1], r[i * 3 + 2]).get_plane().get_normal();
f.surface_index = si ? si[i] : 0;
bw[i].left = -1;
bw[i].right = -1;
bw[i].face_index = i;
bw[i].center = bw[i].aabb.get_center();
}
vertices.resize(db.size());
Vector3 *vw = vertices.ptrw();
for (const KeyValue<Vector3, int> &E : db) {
vw[E.value] = E.key;
}
}
Vector<BVH *> bwptrs;
bwptrs.resize(fc);
BVH **bwp = bwptrs.ptrw();
for (int i = 0; i < fc; i++) {
bwp[i] = &bw[i];
}
max_depth = 0;
int max_alloc = fc;
_create_bvh(bw, bwp, 0, fc, 1, max_depth, max_alloc);
bvh.resize(max_alloc); //resize back
valid = true;
}
Vector3 TriangleMesh::get_area_normal(const AABB &p_aabb) const {
uint32_t *stack = (uint32_t *)alloca(sizeof(int) * max_depth);
enum {
TEST_AABB_BIT = 0,
VISIT_LEFT_BIT = 1,
VISIT_RIGHT_BIT = 2,
VISIT_DONE_BIT = 3,
VISITED_BIT_SHIFT = 29,
NODE_IDX_MASK = (1 << VISITED_BIT_SHIFT) - 1,
VISITED_BIT_MASK = ~NODE_IDX_MASK,
};
int n_count = 0;
Vector3 n;
int level = 0;
const Triangle *triangleptr = triangles.ptr();
// const Vector3 *verticesr = vertices.ptr();
const BVH *bvhptr = bvh.ptr();
int pos = bvh.size() - 1;
stack[0] = pos;
while (true) {
uint32_t node = stack[level] & NODE_IDX_MASK;
const BVH &b = bvhptr[node];
bool done = false;
switch (stack[level] >> VISITED_BIT_SHIFT) {
case TEST_AABB_BIT: {
if (!b.aabb.intersects(p_aabb)) {
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
} else {
if (b.face_index >= 0) {
const Triangle &s = triangleptr[b.face_index];
n += s.normal;
n_count++;
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
} else {
stack[level] = (VISIT_LEFT_BIT << VISITED_BIT_SHIFT) | node;
}
}
continue;
}
case VISIT_LEFT_BIT: {
stack[level] = (VISIT_RIGHT_BIT << VISITED_BIT_SHIFT) | node;
level++;
stack[level] = b.left | TEST_AABB_BIT;
continue;
}
case VISIT_RIGHT_BIT: {
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
level++;
stack[level] = b.right | TEST_AABB_BIT;
continue;
}
case VISIT_DONE_BIT: {
if (level == 0) {
done = true;
break;
} else {
level--;
}
continue;
}
}
if (done) {
break;
}
}
if (n_count > 0) {
n /= n_count;
}
return n;
}
bool TriangleMesh::intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_point, Vector3 &r_normal, int32_t *r_surf_index) const {
uint32_t *stack = (uint32_t *)alloca(sizeof(int) * max_depth);
enum {
TEST_AABB_BIT = 0,
VISIT_LEFT_BIT = 1,
VISIT_RIGHT_BIT = 2,
VISIT_DONE_BIT = 3,
VISITED_BIT_SHIFT = 29,
NODE_IDX_MASK = (1 << VISITED_BIT_SHIFT) - 1,
VISITED_BIT_MASK = ~NODE_IDX_MASK,
};
Vector3 n = (p_end - p_begin).normalized();
real_t d = 1e10;
bool inters = false;
int level = 0;
const Triangle *triangleptr = triangles.ptr();
const Vector3 *vertexptr = vertices.ptr();
const BVH *bvhptr = bvh.ptr();
int pos = bvh.size() - 1;
stack[0] = pos;
while (true) {
uint32_t node = stack[level] & NODE_IDX_MASK;
const BVH &b = bvhptr[node];
bool done = false;
switch (stack[level] >> VISITED_BIT_SHIFT) {
case TEST_AABB_BIT: {
if (!b.aabb.intersects_segment(p_begin, p_end)) {
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
} else {
if (b.face_index >= 0) {
const Triangle &s = triangleptr[b.face_index];
Face3 f3(vertexptr[s.indices[0]], vertexptr[s.indices[1]], vertexptr[s.indices[2]]);
Vector3 res;
if (f3.intersects_segment(p_begin, p_end, &res)) {
real_t nd = n.dot(res);
if (nd < d) {
d = nd;
r_point = res;
r_normal = f3.get_plane().get_normal();
if (r_surf_index) {
*r_surf_index = s.surface_index;
}
inters = true;
}
}
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
} else {
stack[level] = (VISIT_LEFT_BIT << VISITED_BIT_SHIFT) | node;
}
}
continue;
}
case VISIT_LEFT_BIT: {
stack[level] = (VISIT_RIGHT_BIT << VISITED_BIT_SHIFT) | node;
level++;
stack[level] = b.left | TEST_AABB_BIT;
continue;
}
case VISIT_RIGHT_BIT: {
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
level++;
stack[level] = b.right | TEST_AABB_BIT;
continue;
}
case VISIT_DONE_BIT: {
if (level == 0) {
done = true;
break;
} else {
level--;
}
continue;
}
}
if (done) {
break;
}
}
if (inters) {
if (n.dot(r_normal) > 0) {
r_normal = -r_normal;
}
}
return inters;
}
bool TriangleMesh::intersect_ray(const Vector3 &p_begin, const Vector3 &p_dir, Vector3 &r_point, Vector3 &r_normal, int32_t *r_surf_index) const {
uint32_t *stack = (uint32_t *)alloca(sizeof(int) * max_depth);
enum {
TEST_AABB_BIT = 0,
VISIT_LEFT_BIT = 1,
VISIT_RIGHT_BIT = 2,
VISIT_DONE_BIT = 3,
VISITED_BIT_SHIFT = 29,
NODE_IDX_MASK = (1 << VISITED_BIT_SHIFT) - 1,
VISITED_BIT_MASK = ~NODE_IDX_MASK,
};
Vector3 n = p_dir;
real_t d = 1e20;
bool inters = false;
int level = 0;
const Triangle *triangleptr = triangles.ptr();
const Vector3 *vertexptr = vertices.ptr();
const BVH *bvhptr = bvh.ptr();
int pos = bvh.size() - 1;
stack[0] = pos;
while (true) {
uint32_t node = stack[level] & NODE_IDX_MASK;
const BVH &b = bvhptr[node];
bool done = false;
switch (stack[level] >> VISITED_BIT_SHIFT) {
case TEST_AABB_BIT: {
if (!b.aabb.intersects_ray(p_begin, p_dir)) {
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
} else {
if (b.face_index >= 0) {
const Triangle &s = triangleptr[b.face_index];
Face3 f3(vertexptr[s.indices[0]], vertexptr[s.indices[1]], vertexptr[s.indices[2]]);
Vector3 res;
if (f3.intersects_ray(p_begin, p_dir, &res)) {
real_t nd = n.dot(res);
if (nd < d) {
d = nd;
r_point = res;
r_normal = f3.get_plane().get_normal();
if (r_surf_index) {
*r_surf_index = s.surface_index;
}
inters = true;
}
}
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
} else {
stack[level] = (VISIT_LEFT_BIT << VISITED_BIT_SHIFT) | node;
}
}
continue;
}
case VISIT_LEFT_BIT: {
stack[level] = (VISIT_RIGHT_BIT << VISITED_BIT_SHIFT) | node;
level++;
stack[level] = b.left | TEST_AABB_BIT;
continue;
}
case VISIT_RIGHT_BIT: {
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
level++;
stack[level] = b.right | TEST_AABB_BIT;
continue;
}
case VISIT_DONE_BIT: {
if (level == 0) {
done = true;
break;
} else {
level--;
}
continue;
}
}
if (done) {
break;
}
}
if (inters) {
if (n.dot(r_normal) > 0) {
r_normal = -r_normal;
}
}
return inters;
}
bool TriangleMesh::intersect_convex_shape(const Plane *p_planes, int p_plane_count, const Vector3 *p_points, int p_point_count) const {
uint32_t *stack = (uint32_t *)alloca(sizeof(int) * max_depth);
//p_fully_inside = true;
enum {
TEST_AABB_BIT = 0,
VISIT_LEFT_BIT = 1,
VISIT_RIGHT_BIT = 2,
VISIT_DONE_BIT = 3,
VISITED_BIT_SHIFT = 29,
NODE_IDX_MASK = (1 << VISITED_BIT_SHIFT) - 1,
VISITED_BIT_MASK = ~NODE_IDX_MASK,
};
int level = 0;
const Triangle *triangleptr = triangles.ptr();
const Vector3 *vertexptr = vertices.ptr();
const BVH *bvhptr = bvh.ptr();
int pos = bvh.size() - 1;
stack[0] = pos;
while (true) {
uint32_t node = stack[level] & NODE_IDX_MASK;
const BVH &b = bvhptr[node];
bool done = false;
switch (stack[level] >> VISITED_BIT_SHIFT) {
case TEST_AABB_BIT: {
if (!b.aabb.intersects_convex_shape(p_planes, p_plane_count, p_points, p_point_count)) {
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
} else {
if (b.face_index >= 0) {
const Triangle &s = triangleptr[b.face_index];
for (int j = 0; j < 3; ++j) {
const Vector3 &point = vertexptr[s.indices[j]];
const Vector3 &next_point = vertexptr[s.indices[(j + 1) % 3]];
Vector3 res;
bool over = true;
for (int i = 0; i < p_plane_count; i++) {
const Plane &p = p_planes[i];
if (p.intersects_segment(point, next_point, &res)) {
bool inisde = true;
for (int k = 0; k < p_plane_count; k++) {
if (k == i) {
continue;
}
const Plane &pp = p_planes[k];
if (pp.is_point_over(res)) {
inisde = false;
break;
}
}
if (inisde) {
return true;
}
}
if (p.is_point_over(point)) {
over = false;
break;
}
}
if (over) {
return true;
}
}
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
} else {
stack[level] = (VISIT_LEFT_BIT << VISITED_BIT_SHIFT) | node;
}
}
continue;
}
case VISIT_LEFT_BIT: {
stack[level] = (VISIT_RIGHT_BIT << VISITED_BIT_SHIFT) | node;
level++;
stack[level] = b.left | TEST_AABB_BIT;
continue;
}
case VISIT_RIGHT_BIT: {
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
level++;
stack[level] = b.right | TEST_AABB_BIT;
continue;
}
case VISIT_DONE_BIT: {
if (level == 0) {
done = true;
break;
} else {
level--;
}
continue;
}
}
if (done) {
break;
}
}
return false;
}
bool TriangleMesh::inside_convex_shape(const Plane *p_planes, int p_plane_count, const Vector3 *p_points, int p_point_count, Vector3 p_scale) const {
uint32_t *stack = (uint32_t *)alloca(sizeof(int) * max_depth);
enum {
TEST_AABB_BIT = 0,
VISIT_LEFT_BIT = 1,
VISIT_RIGHT_BIT = 2,
VISIT_DONE_BIT = 3,
VISITED_BIT_SHIFT = 29,
NODE_IDX_MASK = (1 << VISITED_BIT_SHIFT) - 1,
VISITED_BIT_MASK = ~NODE_IDX_MASK,
};
int level = 0;
const Triangle *triangleptr = triangles.ptr();
const Vector3 *vertexptr = vertices.ptr();
const BVH *bvhptr = bvh.ptr();
Transform3D scale(Basis().scaled(p_scale));
int pos = bvh.size() - 1;
stack[0] = pos;
while (true) {
uint32_t node = stack[level] & NODE_IDX_MASK;
const BVH &b = bvhptr[node];
bool done = false;
switch (stack[level] >> VISITED_BIT_SHIFT) {
case TEST_AABB_BIT: {
bool intersects = scale.xform(b.aabb).intersects_convex_shape(p_planes, p_plane_count, p_points, p_point_count);
if (!intersects) {
return false;
}
bool inside = scale.xform(b.aabb).inside_convex_shape(p_planes, p_plane_count);
if (inside) {
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
} else {
if (b.face_index >= 0) {
const Triangle &s = triangleptr[b.face_index];
for (int j = 0; j < 3; ++j) {
Vector3 point = scale.xform(vertexptr[s.indices[j]]);
for (int i = 0; i < p_plane_count; i++) {
const Plane &p = p_planes[i];
if (p.is_point_over(point)) {
return false;
}
}
}
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
} else {
stack[level] = (VISIT_LEFT_BIT << VISITED_BIT_SHIFT) | node;
}
}
continue;
}
case VISIT_LEFT_BIT: {
stack[level] = (VISIT_RIGHT_BIT << VISITED_BIT_SHIFT) | node;
level++;
stack[level] = b.left | TEST_AABB_BIT;
continue;
}
case VISIT_RIGHT_BIT: {
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
level++;
stack[level] = b.right | TEST_AABB_BIT;
continue;
}
case VISIT_DONE_BIT: {
if (level == 0) {
done = true;
break;
} else {
level--;
}
continue;
}
}
if (done) {
break;
}
}
return true;
}
bool TriangleMesh::is_valid() const {
return valid;
}
Vector<Face3> TriangleMesh::get_faces() const {
if (!valid) {
return Vector<Face3>();
}
Vector<Face3> faces;
int ts = triangles.size();
faces.resize(triangles.size());
Face3 *w = faces.ptrw();
const Triangle *r = triangles.ptr();
const Vector3 *rv = vertices.ptr();
for (int i = 0; i < ts; i++) {
for (int j = 0; j < 3; j++) {
w[i].vertex[j] = rv[r[i].indices[j]];
}
}
return faces;
}
TriangleMesh::TriangleMesh() {
valid = false;
max_depth = 0;
}
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