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

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

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

/**
	@author AndreaCatania
*/

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 PhysicsDirectSpaceState {
	GDCLASS(BulletPhysicsDirectSpaceState, PhysicsDirectSpaceState);

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 = 0xFFFFFFFF, bool p_collide_with_bodies = true, bool p_collide_with_areas = false);
	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 = 0xFFFFFFFF, bool p_collide_with_bodies = true, bool p_collide_with_areas = false, bool p_pick_ray = false);
	virtual int intersect_shape(const RID &p_shape, const Transform &p_xform, float p_margin, ShapeResult *r_results, int p_result_max, const Set<RID> &p_exclude = Set<RID>(), uint32_t p_collision_mask = 0xFFFFFFFF, bool p_collide_with_bodies = true, bool p_collide_with_areas = false);
	virtual bool cast_motion(const RID &p_shape, const Transform &p_xform, const Vector3 &p_motion, float p_margin, float &r_closest_safe, float &r_closest_unsafe, const Set<RID> &p_exclude = Set<RID>(), uint32_t p_collision_mask = 0xFFFFFFFF, bool p_collide_with_bodies = true, bool p_collide_with_areas = false, ShapeRestInfo *r_info = nullptr);
	/// Returns the list of contacts pairs in this order: Local contact, other body contact
	virtual bool collide_shape(RID p_shape, const Transform &p_shape_xform, float 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 = 0xFFFFFFFF, bool p_collide_with_bodies = true, bool p_collide_with_areas = false);
	virtual bool rest_info(RID p_shape, const Transform &p_shape_xform, float p_margin, ShapeRestInfo *r_info, const Set<RID> &p_exclude = Set<RID>(), uint32_t p_collision_mask = 0xFFFFFFFF, bool p_collide_with_bodies = true, bool p_collide_with_areas = false);
	virtual Vector3 get_closest_point_to_object_volume(RID p_object, const Vector3 p_point) const;
};

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

public:
	/// IMPORTANT NOTE: These members are public to expose some bullet
	/// physics internal functionalities that are not supported or exposed
	/// through the `PhysicsServer`.
	///
	/// One example is the unofficial module `godot-kinematic-body`:
	/// https://github.com/AndreaCatania/godot-kinematic-body/blob/3.x/kinematic_object_3d.cpp
	///
	/// # How it works
	/// To access these members from a module, the first step is to cast the
	/// `PhysicsServer` to `BulletPhysicsServer`. This step is necessary
	/// to have access to the `space_owner` (which is a storage that holds
	/// the `SpaceBullet` objects).
	/// ```c++
	/// BulletPhysicsServer* bullet_physics_singleton = static_cast<BulletPhysicsServer *>(PhysicsServer::get_singleton());
	/// SpaceBullet* space = bullet_physics_singleton->get_space_owner()->getornull(get_world()->get_space());
	/// ```
	//
	/// Once you have access to the space, you can access the members and
	/// execute bullet physics commands:
	/// ```c++
	/// space->dynamicsWorld->convexSweepTest(
	///	p_shape,
	///	btTransform(btMatrix3x3::getIdentity(), p_position),
	///	btTransform(btMatrix3x3::getIdentity(), p_position + p_motion),
	///	result,
	///	p_margin);
	/// ```

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

	btGjkEpaPenetrationDepthSolver *gjk_epa_pen_solver;
	btVoronoiSimplexSolver *gjk_simplex_solver;

	BulletPhysicsDirectSpaceState *direct_access;
	Vector3 gravityDirection;
	real_t gravityMagnitude;

	real_t linear_damp;
	real_t angular_damp;

	Vector<AreaBullet *> areas;

	Vector<Vector3> contactDebug;
	int contactDebugCount;
	real_t delta_time;

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() { return broadphase; }
	_FORCE_INLINE_ btCollisionDispatcher *get_dispatcher() { return dispatcher; }
	_FORCE_INLINE_ btSoftBodyWorldInfo *get_soft_body_world_info() { 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(PhysicsServer::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(PhysicsServer::AreaParameter p_param);

	void set_param(PhysicsServer::SpaceParameter p_param, real_t p_value);
	real_t get_param(PhysicsServer::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.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 Transform &p_from, const Vector3 &p_motion, bool p_infinite_inertia, PhysicsServer::MotionResult *r_result, bool p_exclude_raycast_shapes, const Set<RID> &p_exclude = Set<RID>());
	int test_ray_separation(RigidBodyBullet *p_body, const Transform &p_transform, bool p_infinite_inertia, Vector3 &r_recover_motion, PhysicsServer::SeparationResult *r_results, int p_result_max, float p_margin);

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

public:
	struct RecoverResult {
		bool hasPenetration;
		btVector3 normal;
		btVector3 pointWorld;
		btScalar penetration_distance; // Negative mean penetration
		int other_compound_shape_index;
		const btCollisionObject *other_collision_object;
		int local_shape_most_recovered;

		RecoverResult() :
				hasPenetration(false),
				normal(0, 0, 0),
				pointWorld(0, 0, 0),
				penetration_distance(1e20),
				other_compound_shape_index(0),
				other_collision_object(nullptr),
				local_shape_most_recovered(0) {}
	};

private:
	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(PhysicsServer::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, PhysicsServer::SeparationResult *r_results);
};

#endif // SPACE_BULLET_H
