Fix Geometry3D::get_closest_points_between_segments() returns NaN
Also fix: - Geometry3D::get_closest_distance_between_segments() returning incorrect values. - Test for Geometry3D::get_closest_distance_between_segments() testing for an incorrect value.
This commit is contained in:
Marcel Admiraal
parent
889c522a19
commit
0046d320bb
3 changed files with 108 additions and 91 deletions
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@ -35,6 +35,111 @@
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#include "thirdparty/misc/clipper.hpp"
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#include "thirdparty/misc/polypartition.h"
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void Geometry3D::get_closest_points_between_segments(const Vector3 &p_p0, const Vector3 &p_p1, const Vector3 &p_q0, const Vector3 &p_q1, Vector3 &r_ps, Vector3 &r_qt) {
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// Based on David Eberly's Computation of Distance Between Line Segments algorithm.
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Vector3 p = p_p1 - p_p0;
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Vector3 q = p_q1 - p_q0;
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Vector3 r = p_p0 - p_q0;
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real_t a = p.dot(p);
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real_t b = p.dot(q);
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real_t c = q.dot(q);
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real_t d = p.dot(r);
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real_t e = q.dot(r);
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real_t s = 0.0f;
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real_t t = 0.0f;
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real_t det = a * c - b * b;
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if (det > CMP_EPSILON) {
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// Non-parallel segments
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real_t bte = b * e;
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real_t ctd = c * d;
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if (bte <= ctd) {
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// s <= 0.0f
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if (e <= 0.0f) {
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// t <= 0.0f
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s = (-d >= a ? 1 : (-d > 0.0f ? -d / a : 0.0f));
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t = 0.0f;
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} else if (e < c) {
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// 0.0f < t < 1
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s = 0.0f;
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t = e / c;
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} else {
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// t >= 1
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s = (b - d >= a ? 1 : (b - d > 0.0f ? (b - d) / a : 0.0f));
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t = 1;
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}
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} else {
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// s > 0.0f
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s = bte - ctd;
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if (s >= det) {
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// s >= 1
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if (b + e <= 0.0f) {
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// t <= 0.0f
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s = (-d <= 0.0f ? 0.0f : (-d < a ? -d / a : 1));
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t = 0.0f;
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} else if (b + e < c) {
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// 0.0f < t < 1
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s = 1;
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t = (b + e) / c;
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} else {
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// t >= 1
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s = (b - d <= 0.0f ? 0.0f : (b - d < a ? (b - d) / a : 1));
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t = 1;
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}
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} else {
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// 0.0f < s < 1
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real_t ate = a * e;
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real_t btd = b * d;
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if (ate <= btd) {
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// t <= 0.0f
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s = (-d <= 0.0f ? 0.0f : (-d >= a ? 1 : -d / a));
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t = 0.0f;
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} else {
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// t > 0.0f
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t = ate - btd;
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if (t >= det) {
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// t >= 1
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s = (b - d <= 0.0f ? 0.0f : (b - d >= a ? 1 : (b - d) / a));
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t = 1;
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} else {
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// 0.0f < t < 1
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s /= det;
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t /= det;
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}
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}
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}
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}
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} else {
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// Parallel segments
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if (e <= 0.0f) {
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s = (-d <= 0.0f ? 0.0f : (-d >= a ? 1 : -d / a));
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t = 0.0f;
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} else if (e >= c) {
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s = (b - d <= 0.0f ? 0.0f : (b - d >= a ? 1 : (b - d) / a));
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t = 1;
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} else {
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s = 0.0f;
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t = e / c;
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}
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}
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r_ps = (1 - s) * p_p0 + s * p_p1;
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r_qt = (1 - t) * p_q0 + t * p_q1;
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}
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real_t Geometry3D::get_closest_distance_between_segments(const Vector3 &p_p0, const Vector3 &p_p1, const Vector3 &p_q0, const Vector3 &p_q1) {
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Vector3 ps;
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Vector3 qt;
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get_closest_points_between_segments(p_p0, p_p1, p_q0, p_q1, ps, qt);
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Vector3 st = qt - ps;
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return st.length();
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}
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void Geometry3D::MeshData::optimize_vertices() {
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HashMap<int, int> vtx_remap;
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@ -37,96 +37,8 @@
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class Geometry3D {
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public:
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static void get_closest_points_between_segments(const Vector3 &p1, const Vector3 &p2, const Vector3 &q1, const Vector3 &q2, Vector3 &c1, Vector3 &c2) {
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// Do the function 'd' as defined by pb. I think it's a dot product of some sort.
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#define d_of(m, n, o, p) ((m.x - n.x) * (o.x - p.x) + (m.y - n.y) * (o.y - p.y) + (m.z - n.z) * (o.z - p.z))
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// Calculate the parametric position on the 2 curves, mua and mub.
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real_t mua = (d_of(p1, q1, q2, q1) * d_of(q2, q1, p2, p1) - d_of(p1, q1, p2, p1) * d_of(q2, q1, q2, q1)) / (d_of(p2, p1, p2, p1) * d_of(q2, q1, q2, q1) - d_of(q2, q1, p2, p1) * d_of(q2, q1, p2, p1));
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real_t mub = (d_of(p1, q1, q2, q1) + mua * d_of(q2, q1, p2, p1)) / d_of(q2, q1, q2, q1);
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// Clip the value between [0..1] constraining the solution to lie on the original curves.
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if (mua < 0) {
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mua = 0;
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}
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if (mub < 0) {
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mub = 0;
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}
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if (mua > 1) {
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mua = 1;
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}
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if (mub > 1) {
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mub = 1;
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}
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c1 = p1.lerp(p2, mua);
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c2 = q1.lerp(q2, mub);
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}
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static real_t get_closest_distance_between_segments(const Vector3 &p_from_a, const Vector3 &p_to_a, const Vector3 &p_from_b, const Vector3 &p_to_b) {
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Vector3 u = p_to_a - p_from_a;
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Vector3 v = p_to_b - p_from_b;
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Vector3 w = p_from_a - p_to_a;
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real_t a = u.dot(u); // Always >= 0
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real_t b = u.dot(v);
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real_t c = v.dot(v); // Always >= 0
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real_t d = u.dot(w);
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real_t e = v.dot(w);
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real_t D = a * c - b * b; // Always >= 0
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real_t sc, sN, sD = D; // sc = sN / sD, default sD = D >= 0
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real_t tc, tN, tD = D; // tc = tN / tD, default tD = D >= 0
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// Compute the line parameters of the two closest points.
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if (D < (real_t)CMP_EPSILON) { // The lines are almost parallel.
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sN = 0.0f; // Force using point P0 on segment S1
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sD = 1.0f; // to prevent possible division by 0.0 later.
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tN = e;
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tD = c;
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} else { // Get the closest points on the infinite lines
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sN = (b * e - c * d);
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tN = (a * e - b * d);
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if (sN < 0.0f) { // sc < 0 => the s=0 edge is visible.
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sN = 0.0f;
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tN = e;
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tD = c;
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} else if (sN > sD) { // sc > 1 => the s=1 edge is visible.
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sN = sD;
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tN = e + b;
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tD = c;
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}
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}
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if (tN < 0.0f) { // tc < 0 => the t=0 edge is visible.
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tN = 0.0f;
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// Recompute sc for this edge.
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if (-d < 0.0f) {
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sN = 0.0f;
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} else if (-d > a) {
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sN = sD;
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} else {
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sN = -d;
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sD = a;
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}
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} else if (tN > tD) { // tc > 1 => the t=1 edge is visible.
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tN = tD;
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// Recompute sc for this edge.
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if ((-d + b) < 0.0f) {
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sN = 0;
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} else if ((-d + b) > a) {
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sN = sD;
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} else {
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sN = (-d + b);
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sD = a;
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}
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}
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// Finally do the division to get sc and tc.
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sc = (Math::is_zero_approx(sN) ? 0.0f : sN / sD);
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tc = (Math::is_zero_approx(tN) ? 0.0f : tN / tD);
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// Get the difference of the two closest points.
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Vector3 dP = w + (sc * u) - (tc * v); // = S1(sc) - S2(tc)
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return dP.length(); // Return the closest distance.
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}
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static void get_closest_points_between_segments(const Vector3 &p_p0, const Vector3 &p_p1, const Vector3 &p_q0, const Vector3 &p_q1, Vector3 &r_ps, Vector3 &r_qt);
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static real_t get_closest_distance_between_segments(const Vector3 &p_p0, const Vector3 &p_p1, const Vector3 &p_q0, const Vector3 &p_q1);
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static inline bool ray_intersects_triangle(const Vector3 &p_from, const Vector3 &p_dir, const Vector3 &p_v0, const Vector3 &p_v1, const Vector3 &p_v2, Vector3 *r_res = nullptr) {
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Vector3 e1 = p_v1 - p_v0;
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@ -63,7 +63,7 @@ TEST_CASE("[Geometry3D] Closest Distance Between Segments") {
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p_1(p_p_1), p_2(p_p_2), p_3(p_p_3), p_4(p_p_4), want(p_want){};
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};
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Vector<Case> tt;
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tt.push_back(Case(Vector3(1, -2, 0), Vector3(1, 2, 0), Vector3(-1, 2, 0), Vector3(-1, -2, 0), 0.0f));
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tt.push_back(Case(Vector3(1, -2, 0), Vector3(1, 2, 0), Vector3(-1, 2, 0), Vector3(-1, -2, 0), 2.0f));
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for (int i = 0; i < tt.size(); ++i) {
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Case current_case = tt[i];
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float out = Geometry3D::get_closest_distance_between_segments(current_case.p_1, current_case.p_2, current_case.p_3, current_case.p_4);
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