/*************************************************************************/
/*  skeleton_3d.h                                                        */
/*************************************************************************/
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/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
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#ifndef SKELETON_3D_H
#define SKELETON_3D_H

#include "scene/3d/node_3d.h"
#include "scene/resources/skeleton_modification_3d.h"
#include "scene/resources/skin.h"

typedef int BoneId;

class PhysicalBone3D;
class Skeleton3D;

class SkinReference : public RefCounted {
	GDCLASS(SkinReference, RefCounted)
	friend class Skeleton3D;

	Skeleton3D *skeleton_node = nullptr;
	RID skeleton;
	Ref<Skin> skin;
	uint32_t bind_count = 0;
	uint64_t skeleton_version = 0;
	Vector<uint32_t> skin_bone_indices;
	uint32_t *skin_bone_indices_ptrs = nullptr;
	void _skin_changed();

protected:
	static void _bind_methods();

public:
	RID get_skeleton() const;
	Ref<Skin> get_skin() const;
	~SkinReference();
};

class SkeletonModificationStack3D;

class Skeleton3D : public Node3D {
	GDCLASS(Skeleton3D, Node3D);

private:
	friend class SkinReference;

	struct Bone {
		String name;

		bool enabled;
		int parent;

		Transform3D rest;
		Transform3D global_rest;

		_FORCE_INLINE_ void update_pose_cache() {
			if (pose_cache_dirty) {
				pose_cache.basis.set_quaternion_scale(pose_rotation, pose_scale);
				pose_cache.origin = pose_position;
				pose_cache_dirty = false;
			}
		}
		bool pose_cache_dirty = true;
		Transform3D pose_cache;
		Vector3 pose_position;
		Quaternion pose_rotation;
		Vector3 pose_scale = Vector3(1, 1, 1);

		Transform3D pose_global;
		Transform3D pose_global_no_override;

		real_t global_pose_override_amount = 0.0;
		bool global_pose_override_reset = false;
		Transform3D global_pose_override;

		PhysicalBone3D *physical_bone = nullptr;
		PhysicalBone3D *cache_parent_physical_bone = nullptr;

		real_t local_pose_override_amount;
		bool local_pose_override_reset;
		Transform3D local_pose_override;

		Vector<int> child_bones;

		// The forward direction vector and rest bone forward axis are cached because they do not change
		// 99% of the time, but recalculating them can be expensive on models with many bones.
		Vector3 rest_bone_forward_vector;
		int rest_bone_forward_axis = -1;

		Bone() {
			parent = -1;
			enabled = true;
			global_pose_override_amount = 0;
			global_pose_override_reset = false;
#ifndef _3D_DISABLED
			physical_bone = nullptr;
			cache_parent_physical_bone = nullptr;
#endif // _3D_DISABLED
			local_pose_override_amount = 0;
			local_pose_override_reset = false;
			child_bones = Vector<int>();

			rest_bone_forward_vector = Vector3(0, 0, 0);
			rest_bone_forward_axis = -1;
		}
	};

	HashSet<SkinReference *> skin_bindings;

	void _skin_changed();

	bool animate_physical_bones = true;
	Vector<Bone> bones;
	bool process_order_dirty = false;

	Vector<int> parentless_bones;

	void _make_dirty();
	bool dirty = false;
	bool rest_dirty = false;

	bool show_rest_only = false;
	float motion_scale = 1.0;

	uint64_t version = 1;

	void _update_process_order();

protected:
	bool _get(const StringName &p_path, Variant &r_ret) const;
	bool _set(const StringName &p_path, const Variant &p_value);
	void _get_property_list(List<PropertyInfo> *p_list) const;
	void _validate_property(PropertyInfo &p_property) const;
	void _notification(int p_what);
	static void _bind_methods();

#ifndef _3D_DISABLED
	Ref<SkeletonModificationStack3D> modification_stack;
#endif // _3D_DISABLED

public:
	enum Bone_Forward_Axis {
		BONE_AXIS_X_FORWARD = 0,
		BONE_AXIS_Y_FORWARD = 1,
		BONE_AXIS_Z_FORWARD = 2,
		BONE_AXIS_NEGATIVE_X_FORWARD = 3,
		BONE_AXIS_NEGATIVE_Y_FORWARD = 4,
		BONE_AXIS_NEGATIVE_Z_FORWARD = 5,
	};

	enum {
		NOTIFICATION_UPDATE_SKELETON = 50
	};

	// skeleton creation api
	void add_bone(const String &p_name);
	int find_bone(const String &p_name) const;
	String get_bone_name(int p_bone) const;
	void set_bone_name(int p_bone, const String &p_name);

	bool is_bone_parent_of(int p_bone_id, int p_parent_bone_id) const;

	void set_bone_parent(int p_bone, int p_parent);
	int get_bone_parent(int p_bone) const;

	void unparent_bone_and_rest(int p_bone);

	Vector<int> get_bone_children(int p_bone);
	void set_bone_children(int p_bone, Vector<int> p_children);
	void add_bone_child(int p_bone, int p_child);
	void remove_bone_child(int p_bone, int p_child);
	Vector<int> get_parentless_bones();

	int get_bone_count() const;

	void set_bone_rest(int p_bone, const Transform3D &p_rest);
	Transform3D get_bone_rest(int p_bone) const;
	Transform3D get_bone_global_rest(int p_bone) const;
	Transform3D get_bone_global_pose(int p_bone) const;
	Transform3D get_bone_global_pose_no_override(int p_bone) const;

	void set_bone_enabled(int p_bone, bool p_enabled);
	bool is_bone_enabled(int p_bone) const;

	void set_show_rest_only(bool p_enabled);
	bool is_show_rest_only() const;
	void clear_bones();

	void set_motion_scale(float p_motion_scale);
	float get_motion_scale() const;

	// posing api

	void set_bone_pose_position(int p_bone, const Vector3 &p_position);
	void set_bone_pose_rotation(int p_bone, const Quaternion &p_rotation);
	void set_bone_pose_scale(int p_bone, const Vector3 &p_scale);

	Transform3D get_bone_pose(int p_bone) const;

	Vector3 get_bone_pose_position(int p_bone) const;
	Quaternion get_bone_pose_rotation(int p_bone) const;
	Vector3 get_bone_pose_scale(int p_bone) const;

	void reset_bone_pose(int p_bone);
	void reset_bone_poses();

	void clear_bones_global_pose_override();
	Transform3D get_bone_global_pose_override(int p_bone) const;
	void set_bone_global_pose_override(int p_bone, const Transform3D &p_pose, real_t p_amount, bool p_persistent = false);

	void clear_bones_local_pose_override();
	Transform3D get_bone_local_pose_override(int p_bone) const;
	void set_bone_local_pose_override(int p_bone, const Transform3D &p_pose, real_t p_amount, bool p_persistent = false);

	void localize_rests(); // used for loaders and tools

	Ref<Skin> create_skin_from_rest_transforms();

	Ref<SkinReference> register_skin(const Ref<Skin> &p_skin);

	void force_update_all_dirty_bones();
	void force_update_all_bone_transforms();
	void force_update_bone_children_transforms(int bone_idx);

	void update_bone_rest_forward_vector(int p_bone, bool p_force_update = false);
	void update_bone_rest_forward_axis(int p_bone, bool p_force_update = false);
	Vector3 get_bone_axis_forward_vector(int p_bone);
	int get_bone_axis_forward_enum(int p_bone);

	// Helper functions
	Transform3D global_pose_to_world_transform(Transform3D p_global_pose);
	Transform3D world_transform_to_global_pose(Transform3D p_transform);
	Transform3D global_pose_to_local_pose(int p_bone_idx, Transform3D p_global_pose);
	Transform3D local_pose_to_global_pose(int p_bone_idx, Transform3D p_local_pose);

	Basis global_pose_z_forward_to_bone_forward(int p_bone_idx, Basis p_basis);

	// Modifications
#ifndef _3D_DISABLED
	Ref<SkeletonModificationStack3D> get_modification_stack();
	void set_modification_stack(Ref<SkeletonModificationStack3D> p_stack);
	void execute_modifications(real_t p_delta, int p_execution_mode);
#endif // _3D_DISABLED

	// Physical bone API

	void set_animate_physical_bones(bool p_enabled);
	bool get_animate_physical_bones() const;

	void bind_physical_bone_to_bone(int p_bone, PhysicalBone3D *p_physical_bone);
	void unbind_physical_bone_from_bone(int p_bone);

	PhysicalBone3D *get_physical_bone(int p_bone);
	PhysicalBone3D *get_physical_bone_parent(int p_bone);

private:
	/// This is a slow API, so it's cached
	PhysicalBone3D *_get_physical_bone_parent(int p_bone);
	void _rebuild_physical_bones_cache();

public:
	void physical_bones_stop_simulation();
	void physical_bones_start_simulation_on(const TypedArray<StringName> &p_bones);
	void physical_bones_add_collision_exception(RID p_exception);
	void physical_bones_remove_collision_exception(RID p_exception);

public:
	Skeleton3D();
	~Skeleton3D();
};

#endif // SKELETON_3D_H