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/*  space_bullet.h                                                       */
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#ifndef SPACE_BULLET_H
#define SPACE_BULLET_H

#include "core/templates/vector.h"
#include "core/variant/variant.h"
#include "godot_result_callbacks.h"
#include "rid_bullet.h"
#include "servers/physics_server_3d.h"

#include <BulletCollision/BroadphaseCollision/btBroadphaseProxy.h>
#include <BulletCollision/BroadphaseCollision/btOverlappingPairCache.h>
#include <LinearMath/btScalar.h>
#include <LinearMath/btTransform.h>
#include <LinearMath/btVector3.h>

class AreaBullet;
class btBroadphaseInterface;
class btCollisionDispatcher;
class btConstraintSolver;
class btDefaultCollisionConfiguration;
class btDynamicsWorld;
class btDiscreteDynamicsWorld;
class btEmptyShape;
class btGhostPairCallback;
class btSoftRigidDynamicsWorld;
struct btSoftBodyWorldInfo;
class ConstraintBullet;
class CollisionObjectBullet;
class RigidBodyBullet;
class SpaceBullet;
class SoftBodyBullet;
class btGjkEpaPenetrationDepthSolver;

extern ContactAddedCallback gContactAddedCallback;

class BulletPhysicsDirectSpaceState : public PhysicsDirectSpaceState3D {
	GDCLASS(BulletPhysicsDirectSpaceState, PhysicsDirectSpaceState3D);

private:
	SpaceBullet *space;

public:
	BulletPhysicsDirectSpaceState(SpaceBullet *p_space);

	virtual int intersect_point(const Vector3 &p_point, ShapeResult *r_results, int p_result_max, const Set<RID> &p_exclude = Set<RID>(), uint32_t p_collision_mask = UINT32_MAX, bool p_collide_with_bodies = true, bool p_collide_with_areas = false) override;
	virtual bool intersect_ray(const Vector3 &p_from, const Vector3 &p_to, RayResult &r_result, const Set<RID> &p_exclude = Set<RID>(), uint32_t p_collision_mask = UINT32_MAX, bool p_collide_with_bodies = true, bool p_collide_with_areas = false, bool p_pick_ray = false) override;
	virtual int intersect_shape(const RID &p_shape, const Transform3D &p_xform, real_t p_margin, ShapeResult *r_results, int p_result_max, const Set<RID> &p_exclude = Set<RID>(), uint32_t p_collision_mask = UINT32_MAX, bool p_collide_with_bodies = true, bool p_collide_with_areas = false) override;
	virtual bool cast_motion(const RID &p_shape, const Transform3D &p_xform, const Vector3 &p_motion, real_t p_margin, real_t &r_closest_safe, real_t &r_closest_unsafe, const Set<RID> &p_exclude = Set<RID>(), uint32_t p_collision_mask = UINT32_MAX, bool p_collide_with_bodies = true, bool p_collide_with_areas = false, ShapeRestInfo *r_info = nullptr) override;
	/// Returns the list of contacts pairs in this order: Local contact, other body contact
	virtual bool collide_shape(RID p_shape, const Transform3D &p_shape_xform, real_t p_margin, Vector3 *r_results, int p_result_max, int &r_result_count, const Set<RID> &p_exclude = Set<RID>(), uint32_t p_collision_mask = UINT32_MAX, bool p_collide_with_bodies = true, bool p_collide_with_areas = false) override;
	virtual bool rest_info(RID p_shape, const Transform3D &p_shape_xform, real_t p_margin, ShapeRestInfo *r_info, const Set<RID> &p_exclude = Set<RID>(), uint32_t p_collision_mask = UINT32_MAX, bool p_collide_with_bodies = true, bool p_collide_with_areas = false) override;
	virtual Vector3 get_closest_point_to_object_volume(RID p_object, const Vector3 p_point) const override;
};

class SpaceBullet : public RIDBullet {
	friend class AreaBullet;
	friend void onBulletTickCallback(btDynamicsWorld *world, btScalar timeStep);
	friend class BulletPhysicsDirectSpaceState;

	btBroadphaseInterface *broadphase = nullptr;
	btDefaultCollisionConfiguration *collisionConfiguration = nullptr;
	btCollisionDispatcher *dispatcher = nullptr;
	btConstraintSolver *solver = nullptr;
	btDiscreteDynamicsWorld *dynamicsWorld = nullptr;
	btSoftBodyWorldInfo *soft_body_world_info = nullptr;
	btGhostPairCallback *ghostPairCallback = nullptr;
	GodotFilterCallback *godotFilterCallback = nullptr;

	btGjkEpaPenetrationDepthSolver *gjk_epa_pen_solver = nullptr;
	btVoronoiSimplexSolver *gjk_simplex_solver = nullptr;

	BulletPhysicsDirectSpaceState *direct_access;
	Vector3 gravityDirection = Vector3(0, -1, 0);
	real_t gravityMagnitude = 10.0;

	real_t linear_damp = 0.0;
	real_t angular_damp = 0.0;

	Vector<AreaBullet *> areas;

	Vector<Vector3> contactDebug;
	int contactDebugCount = 0;
	real_t delta_time = 0.;

public:
	SpaceBullet();
	virtual ~SpaceBullet();

	void flush_queries();
	real_t get_delta_time() { return delta_time; }
	void step(real_t p_delta_time);

	_FORCE_INLINE_ btBroadphaseInterface *get_broadphase() const { return broadphase; }
	_FORCE_INLINE_ btDefaultCollisionConfiguration *get_collision_configuration() const { return collisionConfiguration; }
	_FORCE_INLINE_ btCollisionDispatcher *get_dispatcher() const { return dispatcher; }
	_FORCE_INLINE_ btConstraintSolver *get_solver() const { return solver; }
	_FORCE_INLINE_ btDiscreteDynamicsWorld *get_dynamic_world() const { return dynamicsWorld; }
	_FORCE_INLINE_ btSoftBodyWorldInfo *get_soft_body_world_info() const { return soft_body_world_info; }
	_FORCE_INLINE_ bool is_using_soft_world() { return soft_body_world_info; }

	/// Used to set some parameters to Bullet world
	/// @param p_param:
	///     AREA_PARAM_GRAVITY          to set the gravity magnitude of entire world
	///     AREA_PARAM_GRAVITY_VECTOR   to set the gravity direction of entire world
	void set_param(PhysicsServer3D::AreaParameter p_param, const Variant &p_value);
	/// Used to get some parameters to Bullet world
	/// @param p_param:
	///     AREA_PARAM_GRAVITY          to get the gravity magnitude of entire world
	///     AREA_PARAM_GRAVITY_VECTOR   to get the gravity direction of entire world
	Variant get_param(PhysicsServer3D::AreaParameter p_param);

	void set_param(PhysicsServer3D::SpaceParameter p_param, real_t p_value);
	real_t get_param(PhysicsServer3D::SpaceParameter p_param);

	void add_area(AreaBullet *p_area);
	void remove_area(AreaBullet *p_area);
	void reload_collision_filters(AreaBullet *p_area);

	void add_rigid_body(RigidBodyBullet *p_body);
	void remove_rigid_body_constraints(RigidBodyBullet *p_body);
	void remove_rigid_body(RigidBodyBullet *p_body);
	void reload_collision_filters(RigidBodyBullet *p_body);

	void add_soft_body(SoftBodyBullet *p_body);
	void remove_soft_body(SoftBodyBullet *p_body);
	void reload_collision_filters(SoftBodyBullet *p_body);

	void add_constraint(ConstraintBullet *p_constraint, bool disableCollisionsBetweenLinkedBodies = false);
	void remove_constraint(ConstraintBullet *p_constraint);

	int get_num_collision_objects() const;
	void remove_all_collision_objects();

	BulletPhysicsDirectSpaceState *get_direct_state();

	void set_debug_contacts(int p_amount) { contactDebug.resize(p_amount); }
	_FORCE_INLINE_ bool is_debugging_contacts() const { return !contactDebug.is_empty(); }
	_FORCE_INLINE_ void reset_debug_contact_count() {
		contactDebugCount = 0;
	}
	_FORCE_INLINE_ void add_debug_contact(const Vector3 &p_contact) {
		if (contactDebugCount < contactDebug.size()) {
			contactDebug.write[contactDebugCount++] = p_contact;
		}
	}
	_FORCE_INLINE_ Vector<Vector3> get_debug_contacts() { return contactDebug; }
	_FORCE_INLINE_ int get_debug_contact_count() { return contactDebugCount; }

	const Vector3 &get_gravity_direction() const { return gravityDirection; }
	real_t get_gravity_magnitude() const { return gravityMagnitude; }

	void update_gravity();

	real_t get_linear_damp() const { return linear_damp; }
	real_t get_angular_damp() const { return angular_damp; }

	bool test_body_motion(RigidBodyBullet *p_body, const Transform3D &p_from, const Vector3 &p_motion, bool p_infinite_inertia, PhysicsServer3D::MotionResult *r_result, bool p_exclude_raycast_shapes, const Set<RID> &p_exclude = Set<RID>());
	int test_ray_separation(RigidBodyBullet *p_body, const Transform3D &p_transform, bool p_infinite_inertia, Vector3 &r_recover_motion, PhysicsServer3D::SeparationResult *r_results, int p_result_max, real_t p_margin);

private:
	void create_empty_world(bool p_create_soft_world);
	void destroy_world();
	void check_ghost_overlaps();
	void check_body_collision();

	struct RecoverResult {
		bool hasPenetration = false;
		btVector3 normal = btVector3(0, 0, 0);
		btVector3 pointWorld = btVector3(0, 0, 0);
		btScalar penetration_distance = 1e20; // Negative mean penetration
		int other_compound_shape_index = 0;
		const btCollisionObject *other_collision_object = nullptr;
		int local_shape_most_recovered = 0;

		RecoverResult() {}
	};

	bool recover_from_penetration(RigidBodyBullet *p_body, const btTransform &p_body_position, btScalar p_recover_movement_scale, bool p_infinite_inertia, btVector3 &r_delta_recover_movement, RecoverResult *r_recover_result = nullptr, const Set<RID> &p_exclude = Set<RID>());
	/// This is an API that recover a kinematic object from penetration
	/// This allow only Convex Convex test and it always use GJK algorithm, With this API we don't benefit of Bullet special accelerated functions
	bool RFP_convex_convex_test(const btConvexShape *p_shapeA, const btConvexShape *p_shapeB, btCollisionObject *p_objectB, int p_shapeId_A, int p_shapeId_B, const btTransform &p_transformA, const btTransform &p_transformB, btScalar p_recover_movement_scale, btVector3 &r_delta_recover_movement, RecoverResult *r_recover_result = nullptr);
	/// This is an API that recover a kinematic object from penetration
	/// Using this we leave Bullet to select the best algorithm, For example GJK in case we have Convex Convex, or a Bullet accelerated algorithm
	bool RFP_convex_world_test(const btConvexShape *p_shapeA, const btCollisionShape *p_shapeB, btCollisionObject *p_objectA, btCollisionObject *p_objectB, int p_shapeId_A, int p_shapeId_B, const btTransform &p_transformA, const btTransform &p_transformB, btScalar p_recover_movement_scale, btVector3 &r_delta_recover_movement, RecoverResult *r_recover_result = nullptr);

	int add_separation_result(PhysicsServer3D::SeparationResult *r_results, const SpaceBullet::RecoverResult &p_recover_result, int p_shape_id, const btCollisionObject *p_other_object) const;
	int recover_from_penetration_ray(RigidBodyBullet *p_body, const btTransform &p_body_position, btScalar p_recover_movement_scale, bool p_infinite_inertia, int p_result_max, btVector3 &r_delta_recover_movement, PhysicsServer3D::SeparationResult *r_results);
};

#endif // SPACE_BULLET_H