1 files changed, 277 insertions, 0 deletions
diff --git a/include/godot_cpp/core/Quat.cpp b/include/godot_cpp/core/Quat.cpp
new file mode 100644
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--- /dev/null
+++ b/include/godot_cpp/core/Quat.cpp
@@ -0,0 +1,277 @@
+#include "Quat.h"
+
+
+#include <cmath>
+
+#include "Defs.h"
+
+#include "Vector3.h"
+
+#include "Basis.h"
+
+namespace godot {
+
+real_t Quat::length() const
+{
+	return ::sqrt(length_squared());
+}
+
+void Quat::normalize()
+{
+	*this /= length();
+}
+
+Quat Quat::normalized() const
+{
+	return *this / length();
+}
+
+Quat Quat::inverse() const
+{
+	return Quat( -x, -y, -z, w );
+}
+
+void Quat::set_euler(const Vector3& p_euler)
+{
+	real_t half_a1 = p_euler.x * 0.5;
+	real_t half_a2 = p_euler.y * 0.5;
+	real_t half_a3 = p_euler.z * 0.5;
+
+	// R = X(a1).Y(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-2)
+	// a3 is the angle of the first rotation, following the notation in this reference.
+
+	real_t cos_a1 = ::cos(half_a1);
+	real_t sin_a1 = ::sin(half_a1);
+	real_t cos_a2 = ::cos(half_a2);
+	real_t sin_a2 = ::sin(half_a2);
+	real_t cos_a3 = ::cos(half_a3);
+	real_t sin_a3 = ::sin(half_a3);
+
+	set(sin_a1*cos_a2*cos_a3 + sin_a2*sin_a3*cos_a1,
+		-sin_a1*sin_a3*cos_a2 + sin_a2*cos_a1*cos_a3,
+		sin_a1*sin_a2*cos_a3 + sin_a3*cos_a1*cos_a2,
+		-sin_a1*sin_a2*sin_a3 + cos_a1*cos_a2*cos_a3);
+}
+
+Quat Quat::slerp(const Quat& q, const real_t& t) const {
+
+	Quat          to1;
+	real_t        omega, cosom, sinom, scale0, scale1;
+
+
+	// calc cosine
+	cosom = dot(q);
+
+	// adjust signs (if necessary)
+	if ( cosom <0.0 ) {
+		cosom = -cosom;
+		to1.x = - q.x;
+		to1.y = - q.y;
+		to1.z = - q.z;
+		to1.w = - q.w;
+	} else  {
+		to1.x = q.x;
+		to1.y = q.y;
+		to1.z = q.z;
+		to1.w = q.w;
+	}
+
+
+	// calculate coefficients
+
+	if ( (1.0 - cosom) > CMP_EPSILON ) {
+		// standard case (slerp)
+		omega = ::acos(cosom);
+		sinom = ::sin(omega);
+		scale0 = ::sin((1.0 - t) * omega) / sinom;
+		scale1 = ::sin(t * omega) / sinom;
+	} else {
+		// "from" and "to" quaternions are very close
+		//  ... so we can do a linear interpolation
+		scale0 = 1.0 - t;
+		scale1 = t;
+	}
+	// calculate final values
+	return Quat(
+		scale0 * x + scale1 * to1.x,
+		scale0 * y + scale1 * to1.y,
+		scale0 * z + scale1 * to1.z,
+		scale0 * w + scale1 * to1.w
+	);
+}
+
+Quat Quat::slerpni(const Quat& q, const real_t& t) const {
+
+	const Quat &from = *this;
+
+	real_t dot = from.dot(q);
+
+	if (::fabs(dot) > 0.9999) return from;
+
+	real_t	theta		= ::acos(dot),
+		sinT		= 1.0 / ::sin(theta),
+		newFactor	= ::sin(t * theta) * sinT,
+		invFactor	= ::sin((1.0 - t) * theta) * sinT;
+
+	return Quat(invFactor * from.x + newFactor * q.x,
+				invFactor * from.y + newFactor * q.y,
+				invFactor * from.z + newFactor * q.z,
+				invFactor * from.w + newFactor * q.w);
+}
+
+Quat Quat::cubic_slerp(const Quat& q, const Quat& prep, const Quat& postq,const real_t& t) const
+{
+	//the only way to do slerp :|
+	real_t t2 = (1.0-t)*t*2;
+	Quat sp = this->slerp(q,t);
+	Quat sq = prep.slerpni(postq,t);
+	return sp.slerpni(sq,t2);
+}
+
+void Quat::get_axis_and_angle(Vector3& r_axis, real_t &r_angle) const {
+	r_angle = 2 * ::acos(w);
+	r_axis.x = x / ::sqrt(1-w*w);
+	r_axis.y = y / ::sqrt(1-w*w);
+	r_axis.z = z / ::sqrt(1-w*w);
+}
+
+
+
+Quat Quat::operator*(const Vector3& v) const
+{
+	return Quat( w * v.x + y * v.z - z * v.y,
+		w * v.y + z * v.x - x * v.z,
+		w * v.z + x * v.y - y * v.x,
+		-x * v.x - y * v.y - z * v.z);
+}
+
+Vector3 Quat::xform(const Vector3& v) const {
+
+	Quat q = *this * v;
+	q *= this->inverse();
+	return Vector3(q.x,q.y,q.z);
+}
+
+
+Quat::operator String() const
+{
+	return String(); // @Todo
+}
+
+
+Quat::Quat(const Vector3& axis, const real_t& angle)
+{
+	real_t d = axis.length();
+	if (d==0)
+		set(0,0,0,0);
+	else {
+		real_t sin_angle = ::sin(angle * 0.5);
+		real_t cos_angle = ::cos(angle * 0.5);
+		real_t s = sin_angle / d;
+		set(axis.x * s, axis.y * s, axis.z * s,
+			cos_angle);
+	}
+}
+
+Quat::Quat(const Vector3& v0, const Vector3& v1) // shortest arc
+{
+	Vector3 c = v0.cross(v1);
+	real_t  d = v0.dot(v1);
+
+	if (d < -1.0 + CMP_EPSILON) {
+		x=0;
+		y=1;
+		z=0;
+		w=0;
+	} else {
+
+		real_t  s = ::sqrt((1.0 + d) * 2.0);
+		real_t rs = 1.0 / s;
+
+		x=c.x*rs;
+		y=c.y*rs;
+		z=c.z*rs;
+		w=s * 0.5;
+	}
+}
+
+
+real_t Quat::dot(const Quat& q) const {
+	return x * q.x+y * q.y+z * q.z+w * q.w;
+}
+
+real_t Quat::length_squared() const {
+	return dot(*this);
+}
+
+void Quat::operator+=(const Quat& q) {
+	x += q.x; y += q.y; z += q.z; w += q.w;
+}
+
+void Quat::operator-=(const Quat& q) {
+	x -= q.x; y -= q.y; z -= q.z; w -= q.w;
+}
+
+void Quat::operator*=(const Quat& q) {
+	x *= q.x; y *= q.y; z *= q.z; w *= q.w;
+}
+
+
+void Quat::operator*=(const real_t& s) {
+	x *= s; y *= s; z *= s; w *= s;
+}
+
+
+void Quat::operator/=(const real_t& s) {
+
+	*this *= 1.0 / s;
+}
+
+Quat Quat::operator+(const Quat& q2) const {
+	const Quat& q1 = *this;
+	return Quat( q1.x+q2.x, q1.y+q2.y, q1.z+q2.z, q1.w+q2.w );
+}
+
+Quat Quat::operator-(const Quat& q2) const {
+	const Quat& q1 = *this;
+	return Quat( q1.x-q2.x, q1.y-q2.y, q1.z-q2.z, q1.w-q2.w);
+}
+
+Quat Quat::operator*(const Quat& q2) const {
+	Quat q1 = *this;
+	q1 *= q2;
+	return q1;
+}
+
+
+Quat Quat::operator-() const {
+	const Quat& q2 = *this;
+	return Quat( -q2.x, -q2.y,  -q2.z,  -q2.w);
+}
+
+Quat Quat::operator*(const real_t& s) const {
+	return Quat(x * s, y * s, z * s, w * s);
+}
+
+Quat Quat::operator/(const real_t& s) const {
+	return *this * (1.0 / s);
+}
+
+
+bool Quat::operator==(const Quat& p_quat) const {
+	return x==p_quat.x && y==p_quat.y && z==p_quat.z && w==p_quat.w;
+}
+
+bool Quat::operator!=(const Quat& p_quat) const {
+	return x!=p_quat.x || y!=p_quat.y || z!=p_quat.z || w!=p_quat.w;
+}
+
+
+Vector3 Quat::get_euler() const
+{
+	Basis m(*this);
+	return m.get_euler();
+}
+
+}