/*************************************************************************/
/*  Transform.cpp                                                        */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           PANDEMONIUM ENGINE                                */
/*                      https://pandemoniumengine.org                          */
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/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2022 Pandemonium Engine contributors (cf. AUTHORS.md).   */
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#include "transform.h"

#include "basis.h"

#include "aabb.h"
#include "plane.h"

#include "quaternion.h"

const Transform Transform::IDENTITY = Transform();
const Transform Transform::FLIP_X = Transform(-1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0);
const Transform Transform::FLIP_Y = Transform(1, 0, 0, 0, -1, 0, 0, 0, 1, 0, 0, 0);
const Transform Transform::FLIP_Z = Transform(1, 0, 0, 0, 1, 0, 0, 0, -1, 0, 0, 0);

Transform Transform::inverse_xform(const Transform &t) const {
	Vector3 v = t.origin - origin;
	return Transform(basis.transpose_xform(t.basis),
			basis.xform(v));
}

void Transform::set(real_t xx, real_t xy, real_t xz, real_t yx, real_t yy, real_t yz, real_t zx, real_t zy, real_t zz, real_t tx, real_t ty, real_t tz) {
	basis.elements[0][0] = xx;
	basis.elements[0][1] = xy;
	basis.elements[0][2] = xz;
	basis.elements[1][0] = yx;
	basis.elements[1][1] = yy;
	basis.elements[1][2] = yz;
	basis.elements[2][0] = zx;
	basis.elements[2][1] = zy;
	basis.elements[2][2] = zz;
	origin.x = tx;
	origin.y = ty;
	origin.z = tz;
}

Vector3 Transform::xform(const Vector3 &p_vector) const {
	return Vector3(
			basis.elements[0].dot(p_vector) + origin.x,
			basis.elements[1].dot(p_vector) + origin.y,
			basis.elements[2].dot(p_vector) + origin.z);
}
Vector3 Transform::xform_inv(const Vector3 &p_vector) const {
	Vector3 v = p_vector - origin;

	return Vector3(
			(basis.elements[0][0] * v.x) + (basis.elements[1][0] * v.y) + (basis.elements[2][0] * v.z),
			(basis.elements[0][1] * v.x) + (basis.elements[1][1] * v.y) + (basis.elements[2][1] * v.z),
			(basis.elements[0][2] * v.x) + (basis.elements[1][2] * v.y) + (basis.elements[2][2] * v.z));
}

Plane Transform::xform(const Plane &p_plane) const {
	Vector3 point = p_plane.normal * p_plane.d;
	Vector3 point_dir = point + p_plane.normal;
	point = xform(point);
	point_dir = xform(point_dir);

	Vector3 normal = point_dir - point;
	normal.normalize();
	real_t d = normal.dot(point);

	return Plane(normal, d);
}
Plane Transform::xform_inv(const Plane &p_plane) const {
	Vector3 point = p_plane.normal * p_plane.d;
	Vector3 point_dir = point + p_plane.normal;
	point = xform_inv(point);
	point_dir = xform_inv(point_dir);

	Vector3 normal = point_dir - point;
	normal.normalize();
	real_t d = normal.dot(point);

	return Plane(normal, d);
}

AABB Transform::xform(const AABB &p_aabb) const {
	/* define vertices */
	Vector3 x = basis.get_axis(0) * p_aabb.size.x;
	Vector3 y = basis.get_axis(1) * p_aabb.size.y;
	Vector3 z = basis.get_axis(2) * p_aabb.size.z;
	Vector3 pos = xform(p_aabb.position);
	// could be even further optimized
	AABB new_aabb;
	new_aabb.position = pos;
	new_aabb.expand_to(pos + x);
	new_aabb.expand_to(pos + y);
	new_aabb.expand_to(pos + z);
	new_aabb.expand_to(pos + x + y);
	new_aabb.expand_to(pos + x + z);
	new_aabb.expand_to(pos + y + z);
	new_aabb.expand_to(pos + x + y + z);
	return new_aabb;
}
AABB Transform::xform_inv(const AABB &p_aabb) const {
	/* define vertices */
	Vector3 vertices[8] = {
		Vector3(p_aabb.position.x + p_aabb.size.x, p_aabb.position.y + p_aabb.size.y, p_aabb.position.z + p_aabb.size.z),
		Vector3(p_aabb.position.x + p_aabb.size.x, p_aabb.position.y + p_aabb.size.y, p_aabb.position.z),
		Vector3(p_aabb.position.x + p_aabb.size.x, p_aabb.position.y, p_aabb.position.z + p_aabb.size.z),
		Vector3(p_aabb.position.x + p_aabb.size.x, p_aabb.position.y, p_aabb.position.z),
		Vector3(p_aabb.position.x, p_aabb.position.y + p_aabb.size.y, p_aabb.position.z + p_aabb.size.z),
		Vector3(p_aabb.position.x, p_aabb.position.y + p_aabb.size.y, p_aabb.position.z),
		Vector3(p_aabb.position.x, p_aabb.position.y, p_aabb.position.z + p_aabb.size.z),
		Vector3(p_aabb.position.x, p_aabb.position.y, p_aabb.position.z)
	};

	AABB ret;

	ret.position = xform_inv(vertices[0]);

	for (int i = 1; i < 8; i++) {
		ret.expand_to(xform_inv(vertices[i]));
	}

	return ret;
}

void Transform::affine_invert() {
	basis.invert();
	origin = basis.xform(-origin);
}

Transform Transform::affine_inverse() const {
	Transform ret = *this;
	ret.affine_invert();
	return ret;
}

void Transform::invert() {
	basis.transpose();
	origin = basis.xform(-origin);
}

Transform Transform::inverse() const {
	// FIXME: this function assumes the basis is a rotation matrix, with no scaling.
	// Transform::affine_inverse can handle matrices with scaling, so GDScript should eventually use that.
	Transform ret = *this;
	ret.invert();
	return ret;
}

void Transform::rotate(const Vector3 &p_axis, real_t p_phi) {
	*this = rotated(p_axis, p_phi);
}

Transform Transform::rotated(const Vector3 &p_axis, real_t p_phi) const {
	return Transform(Basis(p_axis, p_phi), Vector3()) * (*this);
}

void Transform::rotate_basis(const Vector3 &p_axis, real_t p_phi) {
	basis.rotate(p_axis, p_phi);
}

Transform Transform::looking_at(const Vector3 &p_target, const Vector3 &p_up) const {
	Transform t = *this;
	t.set_look_at(origin, p_target, p_up);
	return t;
}

void Transform::set_look_at(const Vector3 &p_eye, const Vector3 &p_target, const Vector3 &p_up) {
	// Reference: MESA source code
	Vector3 v_x, v_y, v_z;

	/* Make rotation matrix */

	/* Z vector */
	v_z = p_eye - p_target;

	v_z.normalize();

	v_y = p_up;

	v_x = v_y.cross(v_z);

	/* Recompute Y = Z cross X */
	v_y = v_z.cross(v_x);

	v_x.normalize();
	v_y.normalize();

	basis.set_axis(0, v_x);
	basis.set_axis(1, v_y);
	basis.set_axis(2, v_z);
	origin = p_eye;
}

Transform Transform::interpolate_with(const Transform &p_transform, real_t p_c) const {
	/* not sure if very "efficient" but good enough? */

	Vector3 src_scale = basis.get_scale();
	Quaternion src_rot = basis;
	Vector3 src_loc = origin;

	Vector3 dst_scale = p_transform.basis.get_scale();
	Quaternion dst_rot = p_transform.basis;
	Vector3 dst_loc = p_transform.origin;

	Transform dst;
	dst.basis = src_rot.slerp(dst_rot, p_c);
	dst.basis.scale(src_scale.linear_interpolate(dst_scale, p_c));
	dst.origin = src_loc.linear_interpolate(dst_loc, p_c);

	return dst;
}

void Transform::scale(const Vector3 &p_scale) {
	basis.scale(p_scale);
	origin *= p_scale;
}

Transform Transform::scaled(const Vector3 &p_scale) const {
	Transform t = *this;
	t.scale(p_scale);
	return t;
}

void Transform::scale_basis(const Vector3 &p_scale) {
	basis.scale(p_scale);
}

void Transform::translate(real_t p_tx, real_t p_ty, real_t p_tz) {
	translate(Vector3(p_tx, p_ty, p_tz));
}
void Transform::translate(const Vector3 &p_translation) {
	for (int i = 0; i < 3; i++) {
		origin[i] += basis.elements[i].dot(p_translation);
	}
}

Transform Transform::translated(const Vector3 &p_translation) const {
	Transform t = *this;
	t.translate(p_translation);
	return t;
}

void Transform::orthonormalize() {
	basis.orthonormalize();
}

Transform Transform::orthonormalized() const {
	Transform _copy = *this;
	_copy.orthonormalize();
	return _copy;
}

bool Transform::operator==(const Transform &p_transform) const {
	return (basis == p_transform.basis && origin == p_transform.origin);
}
bool Transform::operator!=(const Transform &p_transform) const {
	return (basis != p_transform.basis || origin != p_transform.origin);
}

void Transform::operator*=(const Transform &p_transform) {
	origin = xform(p_transform.origin);
	basis *= p_transform.basis;
}

Transform Transform::operator*(const Transform &p_transform) const {
	Transform t = *this;
	t *= p_transform;
	return t;
}

Transform::operator String() const {
	return basis.operator String() + " - " + origin.operator String();
}

Transform::Transform(const Basis &p_basis, const Vector3 &p_origin) {
	basis = p_basis;
	origin = p_origin;
}