/*************************************************************************/
/*  portal.cpp                                                           */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
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#include "portal.h"

#include "core/engine.h"
#include "mesh_instance.h"
#include "room.h"
#include "room_group.h"
#include "room_manager.h"
#include "scene/main/viewport.h"
#include "servers/visual_server.h"

bool Portal::_portal_plane_convention = false;
bool Portal::_settings_gizmo_show_margins = true;

Portal::Portal() {
	clear();

	_settings_active = true;
	_settings_two_way = true;
	_internal = false;
	_linkedroom_ID[0] = -1;
	_linkedroom_ID[1] = -1;
	_pts_world.clear();
	_pts_local.clear();
	_pts_local_raw.resize(0);
	_pt_center_world = Vector3();
	_plane = Plane();
	_margin = 1.0;
	_use_default_margin = true;

	// the visual server portal lifetime is linked to the lifetime of this object
	_portal_rid = VisualServer::get_singleton()->portal_create();

#ifdef TOOLS_ENABLED
	_room_manager_godot_ID = 0;
#endif

	// portals are defined COUNTER clockwise,
	// because they point OUTWARD from the room in the direction
	// of the normal
	PoolVector<Vector2> points;
	points.resize(4);
	points.set(0, Vector2(1, -1));
	points.set(1, Vector2(1, 1));
	points.set(2, Vector2(-1, 1));
	points.set(3, Vector2(-1, -1));

	set_points(points); // default shape
}

Portal::~Portal() {
	if (_portal_rid != RID()) {
		VisualServer::get_singleton()->free(_portal_rid);
	}
}

String Portal::get_configuration_warning() const {
	String warning = Spatial::get_configuration_warning();

	auto lambda = [](const Node *p_node) {
		return static_cast<bool>((Object::cast_to<RoomManager>(p_node) || Object::cast_to<Room>(p_node) || Object::cast_to<RoomGroup>(p_node)));
	};

	if (Room::detect_nodes_using_lambda(this, lambda)) {
		if (Room::detect_nodes_of_type<RoomManager>(this)) {
			if (!warning.empty()) {
				warning += "\n\n";
			}
			warning += TTR("The RoomManager should not be a child or grandchild of a Portal.");
		}
		if (Room::detect_nodes_of_type<Room>(this)) {
			if (!warning.empty()) {
				warning += "\n\n";
			}
			warning += TTR("A Room should not be a child or grandchild of a Portal.");
		}
		if (Room::detect_nodes_of_type<RoomGroup>(this)) {
			if (!warning.empty()) {
				warning += "\n\n";
			}
			warning += TTR("A RoomGroup should not be a child or grandchild of a Portal.");
		}
	}

	return warning;
}

void Portal::set_point(int p_idx, const Vector2 &p_point) {
	if (p_idx >= _pts_local_raw.size()) {
		return;
	}

	_pts_local_raw.set(p_idx, p_point);
	_sanitize_points();
	update_gizmo();
}

void Portal::set_points(const PoolVector<Vector2> &p_points) {
	_pts_local_raw = p_points;
	_sanitize_points();

	if (is_inside_tree()) {
		portal_update();
		update_gizmo();
	}
}

PoolVector<Vector2> Portal::get_points() const {
	return _pts_local_raw;
}

// extra editor links to the room manager to allow unloading
// on change, or re-converting
void Portal::_changed() {
#ifdef TOOLS_ENABLED
	RoomManager *rm = RoomManager::active_room_manager;
	if (!rm) {
		return;
	}

	rm->_rooms_changed("changed Portal " + get_name());
#endif
}

void Portal::clear() {
	_internal = false;
	_linkedroom_ID[0] = -1;
	_linkedroom_ID[1] = -1;
	_importing_portal = false;
}

void Portal::_notification(int p_what) {
	switch (p_what) {
		case NOTIFICATION_ENTER_WORLD: {
			ERR_FAIL_COND(get_world().is_null());

			// defer full creation of the visual server portal to when the editor portal is in the scene tree
			VisualServer::get_singleton()->portal_set_scenario(_portal_rid, get_world()->get_scenario());

			// we can't calculate world points until we have entered the tree
			portal_update();
			update_gizmo();

		} break;
		case NOTIFICATION_EXIT_WORLD: {
			// partially destroy  the visual server portal when the editor portal exits the scene tree
			VisualServer::get_singleton()->portal_set_scenario(_portal_rid, RID());
		} break;
		case NOTIFICATION_TRANSFORM_CHANGED: {
			// keep the world points and the visual server up to date
			portal_update();

			// In theory we shouldn't need to update the gizmo when the transform
			// changes .. HOWEVER, the portal margin is displayed in world space units,
			// back transformed to model space.
			// If the Z scale is changed by the user, the portal margin length can become incorrect
			// and needs 'resyncing' to the global scale of the portal node.
			// We really only need to do this when Z scale is changed, but it is easier codewise
			// to always change it, unless we have evidence this is a performance problem.
			update_gizmo();
		} break;
	}
}

void Portal::set_portal_active(bool p_active) {
	_settings_active = p_active;
	VisualServer::get_singleton()->portal_set_active(_portal_rid, p_active);
}

bool Portal::get_portal_active() const {
	return _settings_active;
}

void Portal::set_use_default_margin(bool p_use) {
	_use_default_margin = p_use;
	update_gizmo();
}

bool Portal::get_use_default_margin() const {
	return _use_default_margin;
}

void Portal::set_portal_margin(real_t p_margin) {
	_margin = p_margin;

	if (!_use_default_margin) {
		// give visual feedback in the editor for the portal margin zone
		update_gizmo();
	}
}

real_t Portal::get_portal_margin() const {
	return _margin;
}

void Portal::resolve_links(const LocalVector<Room *, int32_t> &p_rooms, const RID &p_from_room_rid) {
	Room *linkedroom = nullptr;
	if (has_node(_settings_path_linkedroom)) {
		linkedroom = Object::cast_to<Room>(get_node(_settings_path_linkedroom));

		// only allow linking to rooms that are part of the roomlist
		// (already recognised).
		// If we don't check this, it will start trying to link to Room nodes that are invalid,
		// and crash.
		if (linkedroom && (p_rooms.find(linkedroom) == -1)) {
			// invalid room
			WARN_PRINT("Portal attempting to link to Room outside the roomlist : " + linkedroom->get_name());
			linkedroom = nullptr;
		}

		// this should not happen, but just in case
		if (linkedroom && (linkedroom->_room_ID >= p_rooms.size())) {
			WARN_PRINT("Portal attempting to link to invalid Room : " + linkedroom->get_name());
			linkedroom = nullptr;
		}
	}

	if (linkedroom) {
		_linkedroom_ID[1] = linkedroom->_room_ID;

		// send to visual server
		VisualServer::get_singleton()->portal_link(_portal_rid, p_from_room_rid, linkedroom->_room_rid, _settings_two_way);
	} else {
		_linkedroom_ID[1] = -1;
	}
}

void Portal::set_linked_room_internal(const NodePath &link_path) {
	_settings_path_linkedroom = link_path;
}

bool Portal::try_set_unique_name(const String &p_name) {
	SceneTree *scene_tree = get_tree();
	if (!scene_tree) {
		// should not happen in the editor
		return false;
	}

	Viewport *root = scene_tree->get_root();
	if (!root) {
		return false;
	}

	Node *found = root->find_node(p_name, true, false);

	// if the name does not already exist in the scene tree, we can use it
	if (!found) {
		set_name(p_name);
		return true;
	}

	// we are trying to set the same name this node already has...
	if (found == this) {
		// noop
		return true;
	}

	return false;
}

void Portal::set_linked_room(const NodePath &link_path) {
	_settings_path_linkedroom = link_path;

	// see if the link looks legit
	Room *linkedroom = nullptr;
	if (has_node(link_path)) {
		linkedroom = Object::cast_to<Room>(get_node(link_path));

		if (linkedroom) {
			if (linkedroom != get_parent()) {
				// was ok
			} else {
				WARN_PRINT("Linked room cannot be the parent room of a portal.");
			}
		} else {
			WARN_PRINT("Linked room path is not a room.");
		}
	}

	_changed();
}

NodePath Portal::get_linked_room() const {
	return _settings_path_linkedroom;
}

void Portal::flip() {
	// flip portal
	Transform tr = get_transform();
	Basis flip_basis = Basis(Vector3(0, Math_PI, 0));
	tr.basis *= flip_basis;
	set_transform(tr);

	_pts_local.clear();
	_pts_world.clear();

	// flip the raw verts
	Vector<Vector2> raw;
	raw.resize(_pts_local_raw.size());
	for (int n = 0; n < _pts_local_raw.size(); n++) {
		const Vector2 &pt = _pts_local_raw[n];
		raw.set(n, Vector2(-pt.x, pt.y));
	}

	// standardize raw verts winding
	Geometry::sort_polygon_winding(raw, false);

	for (int n = 0; n < raw.size(); n++) {
		_pts_local_raw.set(n, raw[n]);
	}

	_sanitize_points();
	portal_update();

	update_gizmo();
}

bool Portal::create_from_mesh_instance(const MeshInstance *p_mi) {
	ERR_FAIL_COND_V(!p_mi, false);

	_pts_local.clear();
	_pts_world.clear();

	Ref<Mesh> rmesh = p_mi->get_mesh();
	ERR_FAIL_COND_V(!rmesh.is_valid(), false);

	if (rmesh->get_surface_count() == 0) {
		WARN_PRINT(vformat("Portal '%s' has no surfaces, ignoring", get_name()));
		return false;
	}

	Array arrays = rmesh->surface_get_arrays(0);
	PoolVector<Vector3> vertices = arrays[VS::ARRAY_VERTEX];
	PoolVector<int> indices = arrays[VS::ARRAY_INDEX];

	// get the model space verts and find center
	int num_source_points = vertices.size();
	ERR_FAIL_COND_V(num_source_points < 3, false);

	const Transform &tr_source = p_mi->get_global_transform();

	Vector<Vector3> pts_world;

	for (int n = 0; n < num_source_points; n++) {
		Vector3 pt = tr_source.xform(vertices[n]);

		// test for duplicates.
		// Some geometry may contain duplicate verts in portals
		// which will muck up the winding etc...
		bool duplicate = false;

		for (int m = 0; m < pts_world.size(); m++) {
			Vector3 diff = pt - pts_world[m];
			// hopefully this epsilon will do in nearly all cases
			if (diff.length() < 0.001) {
				duplicate = true;
				break;
			}
		}

		if (!duplicate) {
			pts_world.push_back(pt);
		}
	}

	ERR_FAIL_COND_V(pts_world.size() < 3, false);

	// create the normal from 3 vertices .. either indexed, or use the first 3
	Vector3 three_pts[3];
	if (indices.size() >= 3) {
		for (int n = 0; n < 3; n++) {
			ERR_FAIL_COND_V(indices[n] >= num_source_points, false);
			three_pts[n] = tr_source.xform(vertices[indices[n]]);
		}
	} else {
		for (int n = 0; n < 3; n++) {
			three_pts[n] = pts_world[n];
		}
	}
	Vector3 normal = Plane(three_pts[0], three_pts[1], three_pts[2]).normal;
	if (_portal_plane_convention) {
		normal = -normal;
	}

	// get the verts sorted with winding, assume that the triangle initial winding
	// tells us the normal and hence which way the world space portal should be facing
	_sort_verts_clockwise(normal, pts_world);

	// back calculate the plane from *all* the portal points, this will give us a nice average plane
	// (in case of wonky portals where artwork isn't bang on)
	_plane = _plane_from_points_newell(pts_world);

	// change the portal transform to match our plane and the center of the portal
	Transform tr_global;

	// prevent warnings when poly normal matches the up vector
	Vector3 up(0, 1, 0);
	if (Math::abs(_plane.normal.dot(up)) > 0.9) {
		up = Vector3(1, 0, 0);
	}

	tr_global.set_look_at(Vector3(0, 0, 0), _plane.normal, up);
	tr_global.origin = _pt_center_world;

	// We can't directly set this global transform on the portal, because the parent node may already
	// have a transform applied, so we need to account for this and give a corrected local transform
	// for the portal, such that the end result global transform will be correct.

	// find the difference between this new global transform and the transform of the parent
	// then use this for the new local transform of the portal
	Spatial *parent = Object::cast_to<Spatial>(get_parent());
	ERR_FAIL_COND_V(!parent, false);

	Transform tr_inverse_parent = parent->get_global_transform().affine_inverse();
	Transform new_local_transform = tr_inverse_parent * tr_global;
	set_transform(new_local_transform);

	// now back calculate the local space coords of the portal from the world space coords.
	// The local space will be used in future for editing and as a 'master' store of the verts.
	_pts_local_raw.resize(pts_world.size());

	// back transform from global space to local space
	Transform tr = tr_global.affine_inverse();

	for (int n = 0; n < pts_world.size(); n++) {
		// pt3 is now in local space
		Vector3 pt3 = tr.xform(pts_world[n]);

		// only the x and y required
		_pts_local_raw.set(n, Vector2(pt3.x, pt3.y));

		// The z coordinate should be approx zero
		// DEV_ASSERT(Math::abs(pt3.z) < 0.1);
	}

	_sanitize_points();
	portal_update();

	return true;
}

void Portal::_update_aabb() {
	_aabb_local = AABB();

	if (_pts_local.size()) {
		Vector3 begin = _vec2to3(_pts_local[0]);
		Vector3 end = begin;

		for (int n = 1; n < _pts_local.size(); n++) {
			Vector3 pt = _vec2to3(_pts_local[n]);

			if (pt.x < begin.x) {
				begin.x = pt.x;
			}
			if (pt.y < begin.y) {
				begin.y = pt.y;
			}
			if (pt.z < begin.z) {
				begin.z = pt.z;
			}

			if (pt.x > end.x) {
				end.x = pt.x;
			}
			if (pt.y > end.y) {
				end.y = pt.y;
			}
			if (pt.z > end.z) {
				end.z = pt.z;
			}
		}

		_aabb_local.position = begin;
		_aabb_local.size = end - begin;
	}
}

void Portal::portal_update() {
	// first calculate the plane from the transform
	// (portals are standardized outward from source room once sanitized,
	// irrespective of the user portal plane convention)
	const Transform &tr = get_global_transform();
	_plane = Plane(0.0, 0.0, -1.0, 0.0);
	_plane = tr.xform(_plane);

	// after becoming a portal, the centre world IS the transform origin
	_pt_center_world = tr.origin;

	// recalculates world points from the local space
	int num_points = _pts_local.size();
	if (_pts_world.size() != num_points) {
		_pts_world.resize(num_points);
	}

	for (int n = 0; n < num_points; n++) {
		_pts_world.set(n, tr.xform(_vec2to3(_pts_local[n])));
	}

	// no need to check winding order, the points are pre-sanitized only when they change

	// extension margin to prevent objects too easily sprawling
	real_t margin = get_active_portal_margin();
	VisualServer::get_singleton()->portal_set_geometry(_portal_rid, _pts_world, margin);
}

real_t Portal::get_active_portal_margin() const {
	if (_use_default_margin) {
		return RoomManager::_get_default_portal_margin();
	}
	return _margin;
}

void Portal::_sanitize_points() {
	// remove duplicates? NYI maybe not necessary
	Vector<Vector2> raw;
	raw.resize(_pts_local_raw.size());
	for (int n = 0; n < _pts_local_raw.size(); n++) {
		raw.set(n, _pts_local_raw[n]);
	}

	// this function may get rid of some concave points due to user editing ..
	// may not be necessary, no idea how fast it is
	_pts_local = Geometry::convex_hull_2d(raw);

	// some pecularity of convex_hull_2d function, it duplicates the last point for some reason
	if (_pts_local.size() > 1) {
		_pts_local.resize(_pts_local.size() - 1);
	}

	// sort winding, the system expects counter clockwise polys
	Geometry::sort_polygon_winding(_pts_local, false);

	// a bit of a bodge, but a small epsilon pulling in the portal edges towards the center
	// can hide walls in the opposite room that abutt the portal (due to floating point error)
	// find 2d center
	Vector2 center;
	for (int n = 0; n < _pts_local.size(); n++) {
		center += _pts_local[n];
	}
	center /= _pts_local.size();

	const real_t pull_in = 0.0001;

	for (int n = 0; n < _pts_local.size(); n++) {
		Vector2 offset = _pts_local[n] - center;
		real_t l = offset.length();

		// don't apply the pull in for tiny holes
		if (l > (pull_in * 2.0)) {
			real_t fract = (l - pull_in) / l;
			offset *= fract;
			_pts_local.set(n, center + offset);
		}
	}

	_update_aabb();
}

void Portal::_sort_verts_clockwise(const Vector3 &p_portal_normal, Vector<Vector3> &r_verts) {
	// cannot sort less than 3 verts
	if (r_verts.size() < 3) {
		return;
	}

	// find centroid
	int num_points = r_verts.size();
	_pt_center_world = Vector3(0, 0, 0);

	for (int n = 0; n < num_points; n++) {
		_pt_center_world += r_verts[n];
	}
	_pt_center_world /= num_points;
	/////////////////////////////////////////

	// now algorithm
	for (int n = 0; n < num_points - 2; n++) {
		Vector3 a = r_verts[n] - _pt_center_world;
		a.normalize();

		Plane p = Plane(r_verts[n], _pt_center_world, _pt_center_world + p_portal_normal);

		double smallest_angle = -1;
		int smallest = -1;

		for (int m = n + 1; m < num_points; m++) {
			if (p.distance_to(r_verts[m]) > 0.0) {
				Vector3 b = r_verts[m] - _pt_center_world;
				b.normalize();

				double angle = a.dot(b);

				if (angle > smallest_angle) {
					smallest_angle = angle;
					smallest = m;
				}
			} // which side

		} // for m

		// swap smallest and n+1 vert
		if (smallest != -1) {
			Vector3 temp = r_verts[smallest];
			r_verts.set(smallest, r_verts[n + 1]);
			r_verts.set(n + 1, temp);
		}
	} // for n

	// the vertices are now sorted, but may be in the opposite order to that wanted.
	// we detect this by calculating the normal of the poly, then flipping the order if the normal is pointing
	// the wrong way.
	Plane plane = Plane(r_verts[0], r_verts[1], r_verts[2]);

	if (p_portal_normal.dot(plane.normal) < 0.0) {
		// reverse winding order of verts
		r_verts.invert();
	}
}

Plane Portal::_plane_from_points_newell(const Vector<Vector3> &p_pts) {
	int num_points = p_pts.size();

	if (num_points < 3) {
		return Plane();
	}

	Vector3 normal;
	Vector3 center;

	for (int i = 0; i < num_points; i++) {
		int j = (i + 1) % num_points;

		const Vector3 &pi = p_pts[i];
		const Vector3 &pj = p_pts[j];

		center += pi;

		normal.x += (((pi.z) + (pj.z)) * ((pj.y) - (pi.y)));
		normal.y += (((pi.x) + (pj.x)) * ((pj.z) - (pi.z)));
		normal.z += (((pi.y) + (pj.y)) * ((pj.x) - (pi.x)));
	}

	normal.normalize();
	center /= num_points;

	_pt_center_world = center;

	// point and normal
	return Plane(center, normal);
}

void Portal::_bind_methods() {
	ClassDB::bind_method(D_METHOD("set_portal_active", "p_active"), &Portal::set_portal_active);
	ClassDB::bind_method(D_METHOD("get_portal_active"), &Portal::get_portal_active);

	ClassDB::bind_method(D_METHOD("set_two_way", "p_two_way"), &Portal::set_two_way);
	ClassDB::bind_method(D_METHOD("is_two_way"), &Portal::is_two_way);

	ClassDB::bind_method(D_METHOD("set_use_default_margin", "p_use"), &Portal::set_use_default_margin);
	ClassDB::bind_method(D_METHOD("get_use_default_margin"), &Portal::get_use_default_margin);

	ClassDB::bind_method(D_METHOD("set_portal_margin", "p_margin"), &Portal::set_portal_margin);
	ClassDB::bind_method(D_METHOD("get_portal_margin"), &Portal::get_portal_margin);

	ClassDB::bind_method(D_METHOD("set_linked_room", "p_room"), &Portal::set_linked_room);
	ClassDB::bind_method(D_METHOD("get_linked_room"), &Portal::get_linked_room);

	ClassDB::bind_method(D_METHOD("set_points", "points"), &Portal::set_points);
	ClassDB::bind_method(D_METHOD("get_points"), &Portal::get_points);

	ClassDB::bind_method(D_METHOD("set_point", "index", "position"), &Portal::set_point);

	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "portal_active"), "set_portal_active", "get_portal_active");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "two_way"), "set_two_way", "is_two_way");
	ADD_PROPERTY(PropertyInfo(Variant::NODE_PATH, "linked_room", PROPERTY_HINT_NODE_PATH_VALID_TYPES, "Room"), "set_linked_room", "get_linked_room");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "use_default_margin"), "set_use_default_margin", "get_use_default_margin");
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "portal_margin", PROPERTY_HINT_RANGE, "0.0,10.0,0.01"), "set_portal_margin", "get_portal_margin");
	ADD_PROPERTY(PropertyInfo(Variant::POOL_VECTOR2_ARRAY, "points"), "set_points", "get_points");
}