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virtualx-engine/core/math/matrix3.cpp

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/*************************************************************************/
/* matrix3.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2017 Godot Engine contributors (cf. AUTHORS.md) */
/* */
/* 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 "matrix3.h"
#include "math_funcs.h"
#include "os/copymem.h"
#include "print_string.h"
#define cofac(row1, col1, row2, col2) \
(elements[row1][col1] * elements[row2][col2] - elements[row1][col2] * elements[row2][col1])
void Basis::from_z(const Vector3 &p_z) {
if (Math::abs(p_z.z) > Math_SQRT12) {
// choose p in y-z plane
real_t a = p_z[1] * p_z[1] + p_z[2] * p_z[2];
real_t k = 1.0 / Math::sqrt(a);
elements[0] = Vector3(0, -p_z[2] * k, p_z[1] * k);
elements[1] = Vector3(a * k, -p_z[0] * elements[0][2], p_z[0] * elements[0][1]);
} else {
// choose p in x-y plane
real_t a = p_z.x * p_z.x + p_z.y * p_z.y;
real_t k = 1.0 / Math::sqrt(a);
elements[0] = Vector3(-p_z.y * k, p_z.x * k, 0);
elements[1] = Vector3(-p_z.z * elements[0].y, p_z.z * elements[0].x, a * k);
}
elements[2] = p_z;
}
void Basis::invert() {
real_t co[3] = {
cofac(1, 1, 2, 2), cofac(1, 2, 2, 0), cofac(1, 0, 2, 1)
};
real_t det = elements[0][0] * co[0] +
elements[0][1] * co[1] +
elements[0][2] * co[2];
#ifdef MATH_CHECKS
ERR_FAIL_COND(det == 0);
#endif
real_t s = 1.0 / det;
set(co[0] * s, cofac(0, 2, 2, 1) * s, cofac(0, 1, 1, 2) * s,
co[1] * s, cofac(0, 0, 2, 2) * s, cofac(0, 2, 1, 0) * s,
co[2] * s, cofac(0, 1, 2, 0) * s, cofac(0, 0, 1, 1) * s);
}
void Basis::orthonormalize() {
#ifdef MATH_CHECKS
ERR_FAIL_COND(determinant() == 0);
#endif
// Gram-Schmidt Process
Vector3 x = get_axis(0);
Vector3 y = get_axis(1);
Vector3 z = get_axis(2);
x.normalize();
y = (y - x * (x.dot(y)));
y.normalize();
z = (z - x * (x.dot(z)) - y * (y.dot(z)));
z.normalize();
set_axis(0, x);
set_axis(1, y);
set_axis(2, z);
}
Basis Basis::orthonormalized() const {
Basis c = *this;
c.orthonormalize();
return c;
}
bool Basis::is_orthogonal() const {
Basis id;
Basis m = (*this) * transposed();
return is_equal_approx(id, m);
}
bool Basis::is_diagonal() const {
return (
Math::is_equal_approx(elements[0][1], 0) && Math::is_equal_approx(elements[0][2], 0) &&
Math::is_equal_approx(elements[1][0], 0) && Math::is_equal_approx(elements[1][2], 0) &&
Math::is_equal_approx(elements[2][0], 0) && Math::is_equal_approx(elements[2][1], 0));
}
bool Basis::is_rotation() const {
return Math::is_equal_approx(determinant(), 1) && is_orthogonal();
}
bool Basis::is_symmetric() const {
if (!Math::is_equal_approx(elements[0][1], elements[1][0]))
return false;
if (!Math::is_equal_approx(elements[0][2], elements[2][0]))
return false;
if (!Math::is_equal_approx(elements[1][2], elements[2][1]))
return false;
return true;
}
Basis Basis::diagonalize() {
//NOTE: only implemented for symmetric matrices
//with the Jacobi iterative method method
#ifdef MATH_CHECKS
ERR_FAIL_COND_V(!is_symmetric(), Basis());
#endif
const int ite_max = 1024;
real_t off_matrix_norm_2 = elements[0][1] * elements[0][1] + elements[0][2] * elements[0][2] + elements[1][2] * elements[1][2];
int ite = 0;
Basis acc_rot;
while (off_matrix_norm_2 > CMP_EPSILON2 && ite++ < ite_max) {
real_t el01_2 = elements[0][1] * elements[0][1];
real_t el02_2 = elements[0][2] * elements[0][2];
real_t el12_2 = elements[1][2] * elements[1][2];
// Find the pivot element
int i, j;
if (el01_2 > el02_2) {
if (el12_2 > el01_2) {
i = 1;
j = 2;
} else {
i = 0;
j = 1;
}
} else {
if (el12_2 > el02_2) {
i = 1;
j = 2;
} else {
i = 0;
j = 2;
}
}
// Compute the rotation angle
real_t angle;
if (Math::is_equal_approx(elements[j][j], elements[i][i])) {
angle = Math_PI / 4;
} else {
angle = 0.5 * Math::atan(2 * elements[i][j] / (elements[j][j] - elements[i][i]));
}
// Compute the rotation matrix
Basis rot;
rot.elements[i][i] = rot.elements[j][j] = Math::cos(angle);
rot.elements[i][j] = -(rot.elements[j][i] = Math::sin(angle));
// Update the off matrix norm
off_matrix_norm_2 -= elements[i][j] * elements[i][j];
// Apply the rotation
*this = rot * *this * rot.transposed();
acc_rot = rot * acc_rot;
}
return acc_rot;
}
Basis Basis::inverse() const {
Basis inv = *this;
inv.invert();
return inv;
}
void Basis::transpose() {
SWAP(elements[0][1], elements[1][0]);
SWAP(elements[0][2], elements[2][0]);
SWAP(elements[1][2], elements[2][1]);
}
Basis Basis::transposed() const {
Basis tr = *this;
tr.transpose();
return tr;
}
// Multiplies the matrix from left by the scaling matrix: M -> S.M
// See the comment for Basis::rotated for further explanation.
void Basis::scale(const Vector3 &p_scale) {
elements[0][0] *= p_scale.x;
elements[0][1] *= p_scale.x;
elements[0][2] *= p_scale.x;
elements[1][0] *= p_scale.y;
elements[1][1] *= p_scale.y;
elements[1][2] *= p_scale.y;
elements[2][0] *= p_scale.z;
elements[2][1] *= p_scale.z;
elements[2][2] *= p_scale.z;
}
Basis Basis::scaled(const Vector3 &p_scale) const {
Basis m = *this;
m.scale(p_scale);
return m;
}
void Basis::set_scale(const Vector3 &p_scale) {
set_axis(0, get_axis(0).normalized() * p_scale.x);
set_axis(1, get_axis(1).normalized() * p_scale.y);
set_axis(2, get_axis(2).normalized() * p_scale.z);
}
Vector3 Basis::get_scale() const {
return Vector3(
Vector3(elements[0][0], elements[1][0], elements[2][0]).length(),
Vector3(elements[0][1], elements[1][1], elements[2][1]).length(),
Vector3(elements[0][2], elements[1][2], elements[2][2]).length());
}
Vector3 Basis::get_signed_scale() const {
// FIXME: We are assuming M = R.S (R is rotation and S is scaling), and use polar decomposition to extract R and S.
// A polar decomposition is M = O.P, where O is an orthogonal matrix (meaning rotation and reflection) and
// P is a positive semi-definite matrix (meaning it contains absolute values of scaling along its diagonal).
//
// Despite being different from what we want to achieve, we can nevertheless make use of polar decomposition
// here as follows. We can split O into a rotation and a reflection as O = R.Q, and obtain M = R.S where
// we defined S = Q.P. Now, R is a proper rotation matrix and S is a (signed) scaling matrix,
// which can involve negative scalings. However, there is a catch: unlike the polar decomposition of M = O.P,
// the decomposition of O into a rotation and reflection matrix as O = R.Q is not unique.
// Therefore, we are going to do this decomposition by sticking to a particular convention.
// This may lead to confusion for some users though.
//
// The convention we use here is to absorb the sign flip into the scaling matrix.
// The same convention is also used in other similar functions such as get_rotation_axis_angle, get_rotation, ...
//
// A proper way to get rid of this issue would be to store the scaling values (or at least their signs)
// as a part of Basis. However, if we go that path, we need to disable direct (write) access to the
// matrix elements.
//
// The rotation part of this decomposition is returned by get_rotation* functions.
real_t det_sign = determinant() > 0 ? 1 : -1;
return det_sign * Vector3(
Vector3(elements[0][0], elements[1][0], elements[2][0]).length(),
Vector3(elements[0][1], elements[1][1], elements[2][1]).length(),
Vector3(elements[0][2], elements[1][2], elements[2][2]).length());
}
// Decomposes a Basis into a rotation-reflection matrix (an element of the group O(3)) and a positive scaling matrix as B = O.S.
// Returns the rotation-reflection matrix via reference argument, and scaling information is returned as a Vector3.
// This (internal) function is too specific and named too ugly to expose to users, and probably there's no need to do so.
Vector3 Basis::rotref_posscale_decomposition(Basis &rotref) const {
#ifdef MATH_CHECKS
ERR_FAIL_COND_V(determinant() == 0, Vector3());
Basis m = transposed() * (*this);
ERR_FAIL_COND_V(m.is_diagonal() == false, Vector3());
#endif
Vector3 scale = get_scale();
Basis inv_scale = Basis().scaled(scale.inverse()); // this will also absorb the sign of scale
rotref = (*this) * inv_scale;
#ifdef MATH_CHECKS
ERR_FAIL_COND_V(rotref.is_orthogonal() == false, Vector3());
#endif
return scale.abs();
}
// Multiplies the matrix from left by the rotation matrix: M -> R.M
// Note that this does *not* rotate the matrix itself.
//
// The main use of Basis is as Transform.basis, which is used a the transformation matrix
// of 3D object. Rotate here refers to rotation of the object (which is R * (*this)),
// not the matrix itself (which is R * (*this) * R.transposed()).
Basis Basis::rotated(const Vector3 &p_axis, real_t p_phi) const {
return Basis(p_axis, p_phi) * (*this);
}
void Basis::rotate(const Vector3 &p_axis, real_t p_phi) {
*this = rotated(p_axis, p_phi);
}
void Basis::rotate_local(const Vector3 &p_axis, real_t p_phi) {
*this = rotated_local(p_axis, p_phi);
}
Basis Basis::rotated_local(const Vector3 &p_axis, real_t p_phi) const {
return (*this) * Basis(p_axis, p_phi);
}
Basis Basis::rotated(const Vector3 &p_euler) const {
return Basis(p_euler) * (*this);
}
void Basis::rotate(const Vector3 &p_euler) {
*this = rotated(p_euler);
}
// TODO: rename this to get_rotation_euler
Vector3 Basis::get_rotation() const {
// Assumes that the matrix can be decomposed into a proper rotation and scaling matrix as M = R.S,
// and returns the Euler angles corresponding to the rotation part, complementing get_scale().
// See the comment in get_scale() for further information.
Basis m = orthonormalized();
real_t det = m.determinant();
if (det < 0) {
// Ensure that the determinant is 1, such that result is a proper rotation matrix which can be represented by Euler angles.
m.scale(Vector3(-1, -1, -1));
}
return m.get_euler();
}
void Basis::get_rotation_axis_angle(Vector3 &p_axis, real_t &p_angle) const {
// Assumes that the matrix can be decomposed into a proper rotation and scaling matrix as M = R.S,
// and returns the Euler angles corresponding to the rotation part, complementing get_scale().
// See the comment in get_scale() for further information.
Basis m = orthonormalized();
real_t det = m.determinant();
if (det < 0) {
// Ensure that the determinant is 1, such that result is a proper rotation matrix which can be represented by Euler angles.
m.scale(Vector3(-1, -1, -1));
}
m.get_axis_angle(p_axis, p_angle);
}
// get_euler_xyz returns a vector containing the Euler angles in the format
// (a1,a2,a3), where a3 is the angle of the first rotation, and a1 is the last
// (following the convention they are commonly defined in the literature).
//
// The current implementation uses XYZ convention (Z is the first rotation),
// so euler.z is the angle of the (first) rotation around Z axis and so on,
//
// And thus, assuming the matrix is a rotation matrix, this function returns
// the angles in the decomposition R = X(a1).Y(a2).Z(a3) where Z(a) rotates
// around the z-axis by a and so on.
Vector3 Basis::get_euler_xyz() const {
// Euler angles in XYZ convention.
// See https://en.wikipedia.org/wiki/Euler_angles#Rotation_matrix
//
// rot = cy*cz -cy*sz sy
// cz*sx*sy+cx*sz cx*cz-sx*sy*sz -cy*sx
// -cx*cz*sy+sx*sz cz*sx+cx*sy*sz cx*cy
Vector3 euler;
#ifdef MATH_CHECKS
ERR_FAIL_COND_V(is_rotation() == false, euler);
#endif
real_t sy = elements[0][2];
if (sy < 1.0) {
if (sy > -1.0) {
// is this a pure Y rotation?
if (elements[1][0] == 0.0 && elements[0][1] == 0.0 && elements[1][2] == 0 && elements[2][1] == 0 && elements[1][1] == 1) {
// return the simplest form (human friendlier in editor and scripts)
euler.x = 0;
euler.y = atan2(elements[0][2], elements[0][0]);
euler.z = 0;
} else {
euler.x = Math::atan2(-elements[1][2], elements[2][2]);
euler.y = Math::asin(sy);
euler.z = Math::atan2(-elements[0][1], elements[0][0]);
}
} else {
euler.x = -Math::atan2(elements[0][1], elements[1][1]);
euler.y = -Math_PI / 2.0;
euler.z = 0.0;
}
} else {
euler.x = Math::atan2(elements[0][1], elements[1][1]);
euler.y = Math_PI / 2.0;
euler.z = 0.0;
}
return euler;
}
// set_euler_xyz expects a vector containing the Euler angles in the format
// (ax,ay,az), where ax is the angle of rotation around x axis,
// and similar for other axes.
// The current implementation uses XYZ convention (Z is the first rotation).
void Basis::set_euler_xyz(const Vector3 &p_euler) {
real_t c, s;
c = Math::cos(p_euler.x);
s = Math::sin(p_euler.x);
Basis xmat(1.0, 0.0, 0.0, 0.0, c, -s, 0.0, s, c);
c = Math::cos(p_euler.y);
s = Math::sin(p_euler.y);
Basis ymat(c, 0.0, s, 0.0, 1.0, 0.0, -s, 0.0, c);
c = Math::cos(p_euler.z);
s = Math::sin(p_euler.z);
Basis zmat(c, -s, 0.0, s, c, 0.0, 0.0, 0.0, 1.0);
//optimizer will optimize away all this anyway
*this = xmat * (ymat * zmat);
}
// get_euler_yxz returns a vector containing the Euler angles in the YXZ convention,
// as in first-Z, then-X, last-Y. The angles for X, Y, and Z rotations are returned
// as the x, y, and z components of a Vector3 respectively.
Vector3 Basis::get_euler_yxz() const {
// Euler angles in YXZ convention.
// See https://en.wikipedia.org/wiki/Euler_angles#Rotation_matrix
//
// rot = cy*cz+sy*sx*sz cz*sy*sx-cy*sz cx*sy
// cx*sz cx*cz -sx
// cy*sx*sz-cz*sy cy*cz*sx+sy*sz cy*cx
Vector3 euler;
#ifdef MATH_CHECKS
ERR_FAIL_COND_V(is_rotation() == false, euler);
#endif
real_t m12 = elements[1][2];
if (m12 < 1) {
if (m12 > -1) {
// is this a pure X rotation?
if (elements[1][0] == 0 && elements[0][1] == 0 && elements[0][2] == 0 && elements[2][0] == 0 && elements[0][0] == 1) {
// return the simplest form (human friendlier in editor and scripts)
euler.x = atan2(-m12, elements[1][1]);
euler.y = 0;
euler.z = 0;
} else {
euler.x = asin(-m12);
euler.y = atan2(elements[0][2], elements[2][2]);
euler.z = atan2(elements[1][0], elements[1][1]);
}
} else { // m12 == -1
euler.x = Math_PI * 0.5;
euler.y = -atan2(-elements[0][1], elements[0][0]);
euler.z = 0;
}
} else { // m12 == 1
euler.x = -Math_PI * 0.5;
euler.y = -atan2(-elements[0][1], elements[0][0]);
euler.z = 0;
}
return euler;
}
// set_euler_yxz expects a vector containing the Euler angles in the format
// (ax,ay,az), where ax is the angle of rotation around x axis,
// and similar for other axes.
// The current implementation uses YXZ convention (Z is the first rotation).
void Basis::set_euler_yxz(const Vector3 &p_euler) {
real_t c, s;
c = Math::cos(p_euler.x);
s = Math::sin(p_euler.x);
Basis xmat(1.0, 0.0, 0.0, 0.0, c, -s, 0.0, s, c);
c = Math::cos(p_euler.y);
s = Math::sin(p_euler.y);
Basis ymat(c, 0.0, s, 0.0, 1.0, 0.0, -s, 0.0, c);
c = Math::cos(p_euler.z);
s = Math::sin(p_euler.z);
Basis zmat(c, -s, 0.0, s, c, 0.0, 0.0, 0.0, 1.0);
//optimizer will optimize away all this anyway
*this = ymat * xmat * zmat;
}
bool Basis::is_equal_approx(const Basis &a, const Basis &b) const {
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
if (Math::is_equal_approx(a.elements[i][j], b.elements[i][j]) == false)
return false;
}
}
return true;
}
bool Basis::operator==(const Basis &p_matrix) const {
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
if (elements[i][j] != p_matrix.elements[i][j])
return false;
}
}
return true;
}
bool Basis::operator!=(const Basis &p_matrix) const {
return (!(*this == p_matrix));
}
Basis::operator String() const {
String mtx;
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
if (i != 0 || j != 0)
mtx += ", ";
mtx += rtos(elements[i][j]);
}
}
return mtx;
}
Quat Basis::get_quat() const {
//commenting this check because precision issues cause it to fail when it shouldn't
//#ifdef MATH_CHECKS
//ERR_FAIL_COND_V(is_rotation() == false, Quat());
//#endif
real_t trace = elements[0][0] + elements[1][1] + elements[2][2];
real_t temp[4];
if (trace > 0.0) {
real_t s = Math::sqrt(trace + 1.0);
temp[3] = (s * 0.5);
s = 0.5 / s;
temp[0] = ((elements[2][1] - elements[1][2]) * s);
temp[1] = ((elements[0][2] - elements[2][0]) * s);
temp[2] = ((elements[1][0] - elements[0][1]) * s);
} else {
int i = elements[0][0] < elements[1][1] ?
(elements[1][1] < elements[2][2] ? 2 : 1) :
(elements[0][0] < elements[2][2] ? 2 : 0);
int j = (i + 1) % 3;
int k = (i + 2) % 3;
real_t s = Math::sqrt(elements[i][i] - elements[j][j] - elements[k][k] + 1.0);
temp[i] = s * 0.5;
s = 0.5 / s;
temp[3] = (elements[k][j] - elements[j][k]) * s;
temp[j] = (elements[j][i] + elements[i][j]) * s;
temp[k] = (elements[k][i] + elements[i][k]) * s;
}
return Quat(temp[0], temp[1], temp[2], temp[3]);
}
static const Basis _ortho_bases[24] = {
Basis(1, 0, 0, 0, 1, 0, 0, 0, 1),
Basis(0, -1, 0, 1, 0, 0, 0, 0, 1),
Basis(-1, 0, 0, 0, -1, 0, 0, 0, 1),
Basis(0, 1, 0, -1, 0, 0, 0, 0, 1),
Basis(1, 0, 0, 0, 0, -1, 0, 1, 0),
Basis(0, 0, 1, 1, 0, 0, 0, 1, 0),
Basis(-1, 0, 0, 0, 0, 1, 0, 1, 0),
Basis(0, 0, -1, -1, 0, 0, 0, 1, 0),
Basis(1, 0, 0, 0, -1, 0, 0, 0, -1),
Basis(0, 1, 0, 1, 0, 0, 0, 0, -1),
Basis(-1, 0, 0, 0, 1, 0, 0, 0, -1),
Basis(0, -1, 0, -1, 0, 0, 0, 0, -1),
Basis(1, 0, 0, 0, 0, 1, 0, -1, 0),
Basis(0, 0, -1, 1, 0, 0, 0, -1, 0),
Basis(-1, 0, 0, 0, 0, -1, 0, -1, 0),
Basis(0, 0, 1, -1, 0, 0, 0, -1, 0),
Basis(0, 0, 1, 0, 1, 0, -1, 0, 0),
Basis(0, -1, 0, 0, 0, 1, -1, 0, 0),
Basis(0, 0, -1, 0, -1, 0, -1, 0, 0),
Basis(0, 1, 0, 0, 0, -1, -1, 0, 0),
Basis(0, 0, 1, 0, -1, 0, 1, 0, 0),
Basis(0, 1, 0, 0, 0, 1, 1, 0, 0),
Basis(0, 0, -1, 0, 1, 0, 1, 0, 0),
Basis(0, -1, 0, 0, 0, -1, 1, 0, 0)
};
int Basis::get_orthogonal_index() const {
//could be sped up if i come up with a way
Basis orth = *this;
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
real_t v = orth[i][j];
if (v > 0.5)
v = 1.0;
else if (v < -0.5)
v = -1.0;
else
v = 0;
orth[i][j] = v;
}
}
for (int i = 0; i < 24; i++) {
if (_ortho_bases[i] == orth)
return i;
}
return 0;
}
void Basis::set_orthogonal_index(int p_index) {
//there only exist 24 orthogonal bases in r3
ERR_FAIL_INDEX(p_index, 24);
*this = _ortho_bases[p_index];
}
void Basis::get_axis_angle(Vector3 &r_axis, real_t &r_angle) const {
#ifdef MATH_CHECKS
ERR_FAIL_COND(is_rotation() == false);
#endif
real_t angle, x, y, z; // variables for result
real_t epsilon = 0.01; // margin to allow for rounding errors
real_t epsilon2 = 0.1; // margin to distinguish between 0 and 180 degrees
if ((Math::abs(elements[1][0] - elements[0][1]) < epsilon) && (Math::abs(elements[2][0] - elements[0][2]) < epsilon) && (Math::abs(elements[2][1] - elements[1][2]) < epsilon)) {
// singularity found
// first check for identity matrix which must have +1 for all terms
// in leading diagonaland zero in other terms
if ((Math::abs(elements[1][0] + elements[0][1]) < epsilon2) && (Math::abs(elements[2][0] + elements[0][2]) < epsilon2) && (Math::abs(elements[2][1] + elements[1][2]) < epsilon2) && (Math::abs(elements[0][0] + elements[1][1] + elements[2][2] - 3) < epsilon2)) {
// this singularity is identity matrix so angle = 0
r_axis = Vector3(0, 1, 0);
r_angle = 0;
return;
}
// otherwise this singularity is angle = 180
angle = Math_PI;
real_t xx = (elements[0][0] + 1) / 2;
real_t yy = (elements[1][1] + 1) / 2;
real_t zz = (elements[2][2] + 1) / 2;
real_t xy = (elements[1][0] + elements[0][1]) / 4;
real_t xz = (elements[2][0] + elements[0][2]) / 4;
real_t yz = (elements[2][1] + elements[1][2]) / 4;
if ((xx > yy) && (xx > zz)) { // elements[0][0] is the largest diagonal term
if (xx < epsilon) {
x = 0;
y = 0.7071;
z = 0.7071;
} else {
x = Math::sqrt(xx);
y = xy / x;
z = xz / x;
}
} else if (yy > zz) { // elements[1][1] is the largest diagonal term
if (yy < epsilon) {
x = 0.7071;
y = 0;
z = 0.7071;
} else {
y = Math::sqrt(yy);
x = xy / y;
z = yz / y;
}
} else { // elements[2][2] is the largest diagonal term so base result on this
if (zz < epsilon) {
x = 0.7071;
y = 0.7071;
z = 0;
} else {
z = Math::sqrt(zz);
x = xz / z;
y = yz / z;
}
}
r_axis = Vector3(x, y, z);
r_angle = angle;
return;
}
// as we have reached here there are no singularities so we can handle normally
real_t s = Math::sqrt((elements[1][2] - elements[2][1]) * (elements[1][2] - elements[2][1]) + (elements[2][0] - elements[0][2]) * (elements[2][0] - elements[0][2]) + (elements[0][1] - elements[1][0]) * (elements[0][1] - elements[1][0])); // s=|axis||sin(angle)|, used to normalise
angle = Math::acos((elements[0][0] + elements[1][1] + elements[2][2] - 1) / 2);
if (angle < 0) s = -s;
x = (elements[2][1] - elements[1][2]) / s;
y = (elements[0][2] - elements[2][0]) / s;
z = (elements[1][0] - elements[0][1]) / s;
r_axis = Vector3(x, y, z);
r_angle = angle;
}
void Basis::set_quat(const Quat &p_quat) {
real_t d = p_quat.length_squared();
real_t s = 2.0 / d;
real_t xs = p_quat.x * s, ys = p_quat.y * s, zs = p_quat.z * s;
real_t wx = p_quat.w * xs, wy = p_quat.w * ys, wz = p_quat.w * zs;
real_t xx = p_quat.x * xs, xy = p_quat.x * ys, xz = p_quat.x * zs;
real_t yy = p_quat.y * ys, yz = p_quat.y * zs, zz = p_quat.z * zs;
set(1.0 - (yy + zz), xy - wz, xz + wy,
xy + wz, 1.0 - (xx + zz), yz - wx,
xz - wy, yz + wx, 1.0 - (xx + yy));
}
void Basis::set_axis_angle(const Vector3 &p_axis, real_t p_phi) {
// Rotation matrix from axis and angle, see https://en.wikipedia.org/wiki/Rotation_matrix#Rotation_matrix_from_axis_angle
#ifdef MATH_CHECKS
ERR_FAIL_COND(p_axis.is_normalized() == false);
#endif
Vector3 axis_sq(p_axis.x * p_axis.x, p_axis.y * p_axis.y, p_axis.z * p_axis.z);
real_t cosine = Math::cos(p_phi);
real_t sine = Math::sin(p_phi);
elements[0][0] = axis_sq.x + cosine * (1.0 - axis_sq.x);
elements[0][1] = p_axis.x * p_axis.y * (1.0 - cosine) - p_axis.z * sine;
elements[0][2] = p_axis.z * p_axis.x * (1.0 - cosine) + p_axis.y * sine;
elements[1][0] = p_axis.x * p_axis.y * (1.0 - cosine) + p_axis.z * sine;
elements[1][1] = axis_sq.y + cosine * (1.0 - axis_sq.y);
elements[1][2] = p_axis.y * p_axis.z * (1.0 - cosine) - p_axis.x * sine;
elements[2][0] = p_axis.z * p_axis.x * (1.0 - cosine) - p_axis.y * sine;
elements[2][1] = p_axis.y * p_axis.z * (1.0 - cosine) + p_axis.x * sine;
elements[2][2] = axis_sq.z + cosine * (1.0 - axis_sq.z);
}
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