multi-screen-projector/engine/thirdparty/manifold/src/tri_dist.h
2025-03-13 08:40:48 +00:00

225 lines
6.5 KiB
C++

// Copyright 2024 The Manifold Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#pragma once
#include <array>
#include "manifold/common.h"
namespace manifold {
// From NVIDIA-Omniverse PhysX - BSD 3-Clause "New" or "Revised" License
// https://github.com/NVIDIA-Omniverse/PhysX/blob/main/LICENSE.md
// https://github.com/NVIDIA-Omniverse/PhysX/blob/main/physx/source/geomutils/src/sweep/GuSweepCapsuleCapsule.cpp
// With minor modifications
/**
* Returns the distance between two line segments.
*
* @param[out] x Closest point on line segment pa.
* @param[out] y Closest point on line segment qb.
* @param[in] p One endpoint of the first line segment.
* @param[in] a Other endpoint of the first line segment.
* @param[in] p One endpoint of the second line segment.
* @param[in] b Other endpoint of the second line segment.
*/
inline void EdgeEdgeDist(vec3& x, vec3& y, // closest points
const vec3& p,
const vec3& a, // seg 1 origin, vector
const vec3& q,
const vec3& b) // seg 2 origin, vector
{
const vec3 T = q - p;
const auto ADotA = la::dot(a, a);
const auto BDotB = la::dot(b, b);
const auto ADotB = la::dot(a, b);
const auto ADotT = la::dot(a, T);
const auto BDotT = la::dot(b, T);
// t parameterizes ray (p, a)
// u parameterizes ray (q, b)
// Compute t for the closest point on ray (p, a) to ray (q, b)
const auto Denom = ADotA * BDotB - ADotB * ADotB;
double t; // We will clamp result so t is on the segment (p, a)
t = Denom != 0.0
? la::clamp((ADotT * BDotB - BDotT * ADotB) / Denom, 0.0, 1.0)
: 0.0;
// find u for point on ray (q, b) closest to point at t
double u;
if (BDotB != 0.0) {
u = (t * ADotB - BDotT) / BDotB;
// if u is on segment (q, b), t and u correspond to closest points,
// otherwise, clamp u, recompute and clamp t
if (u < 0.0) {
u = 0.0;
t = ADotA != 0.0 ? la::clamp(ADotT / ADotA, 0.0, 1.0) : 0.0;
} else if (u > 1.0) {
u = 1.0;
t = ADotA != 0.0 ? la::clamp((ADotB + ADotT) / ADotA, 0.0, 1.0) : 0.0;
}
} else {
u = 0.0;
t = ADotA != 0.0 ? la::clamp(ADotT / ADotA, 0.0, 1.0) : 0.0;
}
x = p + a * t;
y = q + b * u;
}
// From NVIDIA-Omniverse PhysX - BSD 3-Clause "New" or "Revised" License
// https://github.com/NVIDIA-Omniverse/PhysX/blob/main/LICENSE.md
// https://github.com/NVIDIA-Omniverse/PhysX/blob/main/physx/source/geomutils/src/distance/GuDistanceTriangleTriangle.cpp
// With minor modifications
/**
* Returns the minimum squared distance between two triangles.
*
* @param p First triangle.
* @param q Second triangle.
*/
inline auto DistanceTriangleTriangleSquared(const std::array<vec3, 3>& p,
const std::array<vec3, 3>& q) {
std::array<vec3, 3> Sv;
Sv[0] = p[1] - p[0];
Sv[1] = p[2] - p[1];
Sv[2] = p[0] - p[2];
std::array<vec3, 3> Tv;
Tv[0] = q[1] - q[0];
Tv[1] = q[2] - q[1];
Tv[2] = q[0] - q[2];
bool shown_disjoint = false;
auto mindd = std::numeric_limits<double>::max();
for (uint32_t i = 0; i < 3; i++) {
for (uint32_t j = 0; j < 3; j++) {
vec3 cp;
vec3 cq;
EdgeEdgeDist(cp, cq, p[i], Sv[i], q[j], Tv[j]);
const vec3 V = cq - cp;
const auto dd = la::dot(V, V);
if (dd <= mindd) {
mindd = dd;
uint32_t id = i + 2;
if (id >= 3) id -= 3;
vec3 Z = p[id] - cp;
auto a = la::dot(Z, V);
id = j + 2;
if (id >= 3) id -= 3;
Z = q[id] - cq;
auto b = la::dot(Z, V);
if ((a <= 0.0) && (b >= 0.0)) {
return la::dot(V, V);
};
if (a <= 0.0)
a = 0.0;
else if (b > 0.0)
b = 0.0;
if ((mindd - a + b) > 0.0) shown_disjoint = true;
}
}
}
vec3 Sn = la::cross(Sv[0], Sv[1]);
auto Snl = la::dot(Sn, Sn);
if (Snl > 1e-15) {
const vec3 Tp(la::dot(p[0] - q[0], Sn), la::dot(p[0] - q[1], Sn),
la::dot(p[0] - q[2], Sn));
int index = -1;
if ((Tp[0] > 0.0) && (Tp[1] > 0.0) && (Tp[2] > 0.0)) {
index = Tp[0] < Tp[1] ? 0 : 1;
if (Tp[2] < Tp[index]) index = 2;
} else if ((Tp[0] < 0.0) && (Tp[1] < 0.0) && (Tp[2] < 0.0)) {
index = Tp[0] > Tp[1] ? 0 : 1;
if (Tp[2] > Tp[index]) index = 2;
}
if (index >= 0) {
shown_disjoint = true;
const vec3& qIndex = q[index];
vec3 V = qIndex - p[0];
vec3 Z = la::cross(Sn, Sv[0]);
if (la::dot(V, Z) > 0.0) {
V = qIndex - p[1];
Z = la::cross(Sn, Sv[1]);
if (la::dot(V, Z) > 0.0) {
V = qIndex - p[2];
Z = la::cross(Sn, Sv[2]);
if (la::dot(V, Z) > 0.0) {
vec3 cp = qIndex + Sn * Tp[index] / Snl;
vec3 cq = qIndex;
return la::dot(cp - cq, cp - cq);
}
}
}
}
}
vec3 Tn = la::cross(Tv[0], Tv[1]);
auto Tnl = la::dot(Tn, Tn);
if (Tnl > 1e-15) {
const vec3 Sp(la::dot(q[0] - p[0], Tn), la::dot(q[0] - p[1], Tn),
la::dot(q[0] - p[2], Tn));
int index = -1;
if ((Sp[0] > 0.0) && (Sp[1] > 0.0) && (Sp[2] > 0.0)) {
index = Sp[0] < Sp[1] ? 0 : 1;
if (Sp[2] < Sp[index]) index = 2;
} else if ((Sp[0] < 0.0) && (Sp[1] < 0.0) && (Sp[2] < 0.0)) {
index = Sp[0] > Sp[1] ? 0 : 1;
if (Sp[2] > Sp[index]) index = 2;
}
if (index >= 0) {
shown_disjoint = true;
const vec3& pIndex = p[index];
vec3 V = pIndex - q[0];
vec3 Z = la::cross(Tn, Tv[0]);
if (la::dot(V, Z) > 0.0) {
V = pIndex - q[1];
Z = la::cross(Tn, Tv[1]);
if (la::dot(V, Z) > 0.0) {
V = pIndex - q[2];
Z = la::cross(Tn, Tv[2]);
if (la::dot(V, Z) > 0.0) {
vec3 cp = pIndex;
vec3 cq = pIndex + Tn * Sp[index] / Tnl;
return la::dot(cp - cq, cp - cq);
}
}
}
}
}
return shown_disjoint ? mindd : 0.0;
};
} // namespace manifold