godot/core/math/quaternion.cpp

294 lines
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C++

/*************************************************************************/
/* quaternion.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md). */
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/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/*************************************************************************/
#include "quaternion.h"
#include "core/math/basis.h"
#include "core/string/print_string.h"
real_t Quaternion::angle_to(const Quaternion &p_to) const {
real_t d = dot(p_to);
return Math::acos(CLAMP(d * d * 2 - 1, -1, 1));
}
// get_euler_xyz returns 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.
// This implementation uses XYZ convention (Z is the first rotation).
Vector3 Quaternion::get_euler_xyz() const {
Basis m(*this);
return m.get_euler(Basis::EULER_ORDER_XYZ);
}
// get_euler_yxz returns 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.
// This implementation uses YXZ convention (Z is the first rotation).
Vector3 Quaternion::get_euler_yxz() const {
#ifdef MATH_CHECKS
ERR_FAIL_COND_V_MSG(!is_normalized(), Vector3(0, 0, 0), "The quaternion must be normalized.");
#endif
Basis m(*this);
return m.get_euler(Basis::EULER_ORDER_YXZ);
}
void Quaternion::operator*=(const Quaternion &p_q) {
real_t xx = w * p_q.x + x * p_q.w + y * p_q.z - z * p_q.y;
real_t yy = w * p_q.y + y * p_q.w + z * p_q.x - x * p_q.z;
real_t zz = w * p_q.z + z * p_q.w + x * p_q.y - y * p_q.x;
w = w * p_q.w - x * p_q.x - y * p_q.y - z * p_q.z;
x = xx;
y = yy;
z = zz;
}
Quaternion Quaternion::operator*(const Quaternion &p_q) const {
Quaternion r = *this;
r *= p_q;
return r;
}
bool Quaternion::is_equal_approx(const Quaternion &p_quaternion) const {
return Math::is_equal_approx(x, p_quaternion.x) && Math::is_equal_approx(y, p_quaternion.y) && Math::is_equal_approx(z, p_quaternion.z) && Math::is_equal_approx(w, p_quaternion.w);
}
real_t Quaternion::length() const {
return Math::sqrt(length_squared());
}
void Quaternion::normalize() {
*this /= length();
}
Quaternion Quaternion::normalized() const {
return *this / length();
}
bool Quaternion::is_normalized() const {
return Math::is_equal_approx(length_squared(), 1, (real_t)UNIT_EPSILON); //use less epsilon
}
Quaternion Quaternion::inverse() const {
#ifdef MATH_CHECKS
ERR_FAIL_COND_V_MSG(!is_normalized(), Quaternion(), "The quaternion must be normalized.");
#endif
return Quaternion(-x, -y, -z, w);
}
Quaternion Quaternion::log() const {
Quaternion src = *this;
Vector3 src_v = src.get_axis() * src.get_angle();
return Quaternion(src_v.x, src_v.y, src_v.z, 0);
}
Quaternion Quaternion::exp() const {
Quaternion src = *this;
Vector3 src_v = Vector3(src.x, src.y, src.z);
real_t theta = src_v.length();
if (theta < CMP_EPSILON) {
return Quaternion(0, 0, 0, 1);
}
return Quaternion(src_v.normalized(), theta);
}
Quaternion Quaternion::slerp(const Quaternion &p_to, const real_t &p_weight) const {
#ifdef MATH_CHECKS
ERR_FAIL_COND_V_MSG(!is_normalized(), Quaternion(), "The start quaternion must be normalized.");
ERR_FAIL_COND_V_MSG(!p_to.is_normalized(), Quaternion(), "The end quaternion must be normalized.");
#endif
Quaternion to1;
real_t omega, cosom, sinom, scale0, scale1;
// calc cosine
cosom = dot(p_to);
// adjust signs (if necessary)
if (cosom < 0.0f) {
cosom = -cosom;
to1 = -p_to;
} else {
to1 = p_to;
}
// calculate coefficients
if ((1.0f - cosom) > (real_t)CMP_EPSILON) {
// standard case (slerp)
omega = Math::acos(cosom);
sinom = Math::sin(omega);
scale0 = Math::sin((1.0 - p_weight) * omega) / sinom;
scale1 = Math::sin(p_weight * omega) / sinom;
} else {
// "from" and "to" quaternions are very close
// ... so we can do a linear interpolation
scale0 = 1.0f - p_weight;
scale1 = p_weight;
}
// calculate final values
return Quaternion(
scale0 * x + scale1 * to1.x,
scale0 * y + scale1 * to1.y,
scale0 * z + scale1 * to1.z,
scale0 * w + scale1 * to1.w);
}
Quaternion Quaternion::slerpni(const Quaternion &p_to, const real_t &p_weight) const {
#ifdef MATH_CHECKS
ERR_FAIL_COND_V_MSG(!is_normalized(), Quaternion(), "The start quaternion must be normalized.");
ERR_FAIL_COND_V_MSG(!p_to.is_normalized(), Quaternion(), "The end quaternion must be normalized.");
#endif
const Quaternion &from = *this;
real_t dot = from.dot(p_to);
if (Math::absf(dot) > 0.9999f) {
return from;
}
real_t theta = Math::acos(dot),
sinT = 1.0f / Math::sin(theta),
newFactor = Math::sin(p_weight * theta) * sinT,
invFactor = Math::sin((1.0f - p_weight) * theta) * sinT;
return Quaternion(invFactor * from.x + newFactor * p_to.x,
invFactor * from.y + newFactor * p_to.y,
invFactor * from.z + newFactor * p_to.z,
invFactor * from.w + newFactor * p_to.w);
}
Quaternion Quaternion::spherical_cubic_interpolate(const Quaternion &p_b, const Quaternion &p_pre_a, const Quaternion &p_post_b, const real_t &p_weight) const {
#ifdef MATH_CHECKS
ERR_FAIL_COND_V_MSG(!is_normalized(), Quaternion(), "The start quaternion must be normalized.");
ERR_FAIL_COND_V_MSG(!p_b.is_normalized(), Quaternion(), "The end quaternion must be normalized.");
#endif
Quaternion ret_q = *this;
Quaternion pre_q = p_pre_a;
Quaternion to_q = p_b;
Quaternion post_q = p_post_b;
// Align flip phases.
ret_q = Basis(ret_q).get_rotation_quaternion();
pre_q = Basis(pre_q).get_rotation_quaternion();
to_q = Basis(to_q).get_rotation_quaternion();
post_q = Basis(post_q).get_rotation_quaternion();
// Flip quaternions to shortest path if necessary.
bool flip1 = signbit(ret_q.dot(pre_q));
pre_q = flip1 ? -pre_q : pre_q;
bool flip2 = signbit(ret_q.dot(to_q));
to_q = flip2 ? -to_q : to_q;
bool flip3 = flip2 ? to_q.dot(post_q) <= 0 : signbit(to_q.dot(post_q));
post_q = flip3 ? -post_q : post_q;
if (flip1 || flip2 || flip3) {
// Angle is too large, calc by Approximate.
ret_q.x = Math::cubic_interpolate(ret_q.x, to_q.x, pre_q.x, post_q.x, p_weight);
ret_q.y = Math::cubic_interpolate(ret_q.y, to_q.y, pre_q.y, post_q.y, p_weight);
ret_q.z = Math::cubic_interpolate(ret_q.z, to_q.z, pre_q.z, post_q.z, p_weight);
ret_q.w = Math::cubic_interpolate(ret_q.w, to_q.w, pre_q.w, post_q.w, p_weight);
ret_q.normalize();
} else {
// Calc by Expmap.
Quaternion ln_ret = ret_q.log();
Quaternion ln_to = to_q.log();
Quaternion ln_pre = pre_q.log();
Quaternion ln_post = post_q.log();
Quaternion ln = Quaternion(0, 0, 0, 0);
ln.x = Math::cubic_interpolate(ln_ret.x, ln_to.x, ln_pre.x, ln_post.x, p_weight);
ln.y = Math::cubic_interpolate(ln_ret.y, ln_to.y, ln_pre.y, ln_post.y, p_weight);
ln.z = Math::cubic_interpolate(ln_ret.z, ln_to.z, ln_pre.z, ln_post.z, p_weight);
ret_q = ln.exp();
}
return ret_q;
}
Quaternion::operator String() const {
return "(" + String::num_real(x, false) + ", " + String::num_real(y, false) + ", " + String::num_real(z, false) + ", " + String::num_real(w, false) + ")";
}
Vector3 Quaternion::get_axis() const {
if (Math::abs(w) > 1 - CMP_EPSILON) {
return Vector3(x, y, z);
}
real_t r = ((real_t)1) / Math::sqrt(1 - w * w);
return Vector3(x * r, y * r, z * r);
}
real_t Quaternion::get_angle() const {
return 2 * Math::acos(w);
}
Quaternion::Quaternion(const Vector3 &p_axis, real_t p_angle) {
#ifdef MATH_CHECKS
ERR_FAIL_COND_MSG(!p_axis.is_normalized(), "The axis Vector3 must be normalized.");
#endif
real_t d = p_axis.length();
if (d == 0) {
x = 0;
y = 0;
z = 0;
w = 0;
} else {
real_t sin_angle = Math::sin(p_angle * 0.5f);
real_t cos_angle = Math::cos(p_angle * 0.5f);
real_t s = sin_angle / d;
x = p_axis.x * s;
y = p_axis.y * s;
z = p_axis.z * s;
w = cos_angle;
}
}
// Euler constructor 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.
// This implementation uses YXZ convention (Z is the first rotation).
Quaternion::Quaternion(const Vector3 &p_euler) {
real_t half_a1 = p_euler.y * 0.5f;
real_t half_a2 = p_euler.x * 0.5f;
real_t half_a3 = p_euler.z * 0.5f;
// R = Y(a1).X(a2).Z(a3) convention for Euler angles.
// Conversion to quaternion as listed in https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770024290.pdf (page A-6)
// a3 is the angle of the first rotation, following the notation in this reference.
real_t cos_a1 = Math::cos(half_a1);
real_t sin_a1 = Math::sin(half_a1);
real_t cos_a2 = Math::cos(half_a2);
real_t sin_a2 = Math::sin(half_a2);
real_t cos_a3 = Math::cos(half_a3);
real_t sin_a3 = Math::sin(half_a3);
x = sin_a1 * cos_a2 * sin_a3 + cos_a1 * sin_a2 * cos_a3;
y = sin_a1 * cos_a2 * cos_a3 - cos_a1 * sin_a2 * sin_a3;
z = -sin_a1 * sin_a2 * cos_a3 + cos_a1 * cos_a2 * sin_a3;
w = sin_a1 * sin_a2 * sin_a3 + cos_a1 * cos_a2 * cos_a3;
}