godot::CarPhysics Class Reference

Subclass Sandbox for car physics. Uses _integrate_forces and local_velocity to abstract the behaviour of a physical car. More...

#include <car_physics.hpp>

Inheritance diagram for godot::CarPhysics:

Public Member Functions
virtual void	_enter_tree () override
	Enable _integrate_forces, fetch child nodes, and setup contact monitoring.
virtual void	_physics_process (double delta_time) override
	Fixed-interval process function. Split into process_oversteer and process_understeer.
void	process_oversteer (double delta_time)
	Process the current_oversteer member variable.
void	process_understeer (double delta_time)
	Process the current_understeer member variable.
virtual void	_integrate_forces (PhysicsDirectBodyState3D *state) override
	Custom force integrator. Split into integrate_steering, integrate_engine_acceleration and integrate_oversteer. After calling other integrate_* functions, applies local_velocity to state.velocity.
Vector3	get_local_velocity () const
	Public getter for current local velocity.
Vector3	local_to_world_velocity () const
	transform the current local_velocity to world coordinates
Vector3	world_to_local_velocity () const
	transform the current world velocity to local coordinates
float	get_current_speed () const
	The current forward velocity (local_velocity.z)
void	set_target_speed (float target)
	The target speed.
float	get_target_speed () const
	The target speed.
void	set_current_steering (float steering)
	The current steering input.
float	get_current_steering () const
	The current steering input.
void	set_brake (bool value)
	True if the hand-brake is currently active.
bool	get_brake () const
	True if the hand-brake is currently active.
void	set_oversteer_curve (Ref< Curve > curve)
	The base curve used for oversteering.
Ref< Curve >	get_oversteer_curve () const
	The base curve used for oversteering.
void	set_oversteer_curve_x_scale (float scale)
	The amount of speed represented by x=1 on the oversteer curve.
float	get_oversteer_curve_x_scale () const
	The amount of speed represented by x=1 on the oversteer curve.
void	set_understeer_curve (Ref< Curve > curve)
	The base curve used for understeering.
Ref< Curve >	get_understeer_curve () const
	The base curve used for understeering.
void	set_understeer_curve_x_scale (float scale)
	The amount of speed represented by x=1 on the understeer curve.
float	get_understeer_curve_x_scale () const
	The amount of speed represented by x=1 on the understeer curve.
void	set_acceleration (float value)
	The base engine acceleration of this car.
float	get_acceleration () const
	The base engine acceleration of this car.
void	set_engine_brake_force (float value)
	The base engine braking force of this car.
float	get_engine_brake_force () const
	The base engine braking force of this car.
void	set_handbrake_force (float value)
	The amount of braking force applied by the handbrake.
float	get_handbrake_force () const
	The amount of braking force applied by the handbrake.
void	set_handbrake_oversteer (float value)
	The modifier applied to oversteering when the handbrake is active.
float	get_handbrake_oversteer () const
	The modifier applied to oversteering when the handbrake is active.
void	set_traction_recovery_speed (float value)
	The speed at which the car will return to regular traction after under- or oversteering.
float	get_traction_recovery_speed () const
	The speed at which the car will return to regular traction after under- or oversteering.
void	set_max_slide_speed (float value)
	The maximum sideways speed that can be reached while drifting.
float	get_max_slide_speed () const
	The maximum sideways speed that can be reached while drifting.
void	set_slide_speed_acceleration (float value)
	The sideways acceleration applied when drifting.
float	get_slide_speed_acceleration () const
	The sideways acceleration applied when drifting.
void	set_oversteer_speed_penalty (float value)
	Deceleration applied to forward speed when oversteering.
float	get_oversteer_speed_penalty () const
	Deceleration applied to forward speed when oversteering.
void	set_oversteer_brake_penalty (float value)
	Modifier applied to brake force when oversteering.
float	get_oversteer_brake_penalty () const
	Modifier applied to brake force when oversteering.
void	set_oversteer_steering_speed (float value)
	Modifier applied to brake force when oversteering.
float	get_oversteer_steering_speed () const
	Base amount of steering applied while oversteering.
void	set_slide_resistance (float value)
	Deceleration applied to sideways velocity.
float	get_slide_resistance () const
	Deceleration applied to sideways velocity.
void	set_steering_inward_speed (float value)
	Target amount of velocity towards the centre of a turn while steering.
float	get_steering_inward_speed () const
	Target amount of velocity towards the centre of a turn while steering.

Protected Member Functions
void	integrate_steering (PhysicsDirectBodyState3D *state)
	Integrate steering into angular and local x velocities. As a side-effect this also applies sliding resistance and sliding recovery. Also detects crashes to avoid glitchy behaviour when accelerating into a wall.
void	integrate_engine_acceleration (PhysicsDirectBodyState3D *state)
	Apply velocity along local z. Accelerates towards value returned by get_true_target_speed at get_current_acceleration m/s^2.
void	integrate_oversteer (PhysicsDirectBodyState3D *state)
	Integrate oversteering to local_velocity to allow drifting.
void	on_body_shape_entered (RID body_rid, Node *node, int body_shape_index, int local_shape_index)
	Detect that an object started colliding with the wheels.
void	on_body_shape_exited (RID body_rid, Node *node, int body_shape_index, int local_shape_index)
	Detect that an object lost contact with the wheels.
float	evaluate_oversteer_curve (float speed) const
	evaluate the oversteer curve with a speed, taking *_x_scale into account
float	evaluate_understeer_curve (float speed) const
	evaluate the understeer curve with a speed, taking *_x_scale into account
float	get_true_target_speed () const
	Returns the maximum speed modified by under/oversteer.
bool	is_grounded () const
	Returns true if there is at least one contact with either of the wheels.
float	get_current_acceleration () const
	Returns acceleration, taking into account braking, throttle, and handbrake.

Private Member Functions
	GDCLASS (CarPhysics, RigidBody3D)

Static Private Member Functions
static void	_bind_methods ()
	Registers functions and properties.

Private Attributes
Vector3	last_velocity {0.f, 0.f, 0.f}
	Acceleration at the end of the integration step of the last frame.
Vector3	local_velocity {0.f, 0.f, 0.f}
	Velocity relative to the local transform.
float	target_speed {0.f}
	Target value for local_velocity.z.
float	current_steering {0.f}
	Current steering input.
bool	brake {false}
	While true, the handbrake is on.
Ref< Curve >	oversteer_curve {}
float	oversteer_curve_x_scale {50.f}
Ref< Curve >	understeer_curve {}
float	understeer_curve_x_scale {50.f}
float	acceleration {20.f}
float	engine_brake_force {30.f}
float	handbrake_force {40.f}
float	handbrake_oversteer {1.f}
float	traction_recovery_speed {1.f}
float	max_slide_speed {20.f}
float	slide_speed_acceleration {0.05f}
float	oversteer_speed_penalty {5.f}
float	oversteer_brake_penalty {0.25f}
float	oversteer_steering_speed {0.7f}
float	understeer_speed_penalty {3.f}
float	slide_resistance {20.f}
float	steering_inward_speed {0.1f}
HashSet< Node * >	grounded_objects {}
CollisionShape3D *	front_wheels {nullptr}
CollisionShape3D *	back_wheels {nullptr}
float	current_understeer {0.f}
float	current_oversteer {0.f}

Detailed Description

Subclass Sandbox for car physics. Uses _integrate_forces and local_velocity to abstract the behaviour of a physical car.

Member Function Documentation

_bind_methods()

void godot::CarPhysics::_bind_methods ( )

staticprivate

Registers functions and properties.

_enter_tree()

void godot::CarPhysics::_enter_tree ( )

overridevirtual

Enable _integrate_forces, fetch child nodes, and setup contact monitoring.

Reimplemented in godot::EnemyCar.

_integrate_forces()

void godot::CarPhysics::_integrate_forces ( PhysicsDirectBodyState3D *  state )

overridevirtual

Custom force integrator. Split into integrate_steering, integrate_engine_acceleration and integrate_oversteer. After calling other integrate_* functions, applies local_velocity to state.velocity.

_physics_process()

void godot::CarPhysics::_physics_process ( double  delta_time )

overridevirtual

Fixed-interval process function. Split into process_oversteer and process_understeer.

evaluate_oversteer_curve()

float godot::CarPhysics::evaluate_oversteer_curve ( float  speed ) const

protected

evaluate the oversteer curve with a speed, taking *_x_scale into account

evaluate_understeer_curve()

float godot::CarPhysics::evaluate_understeer_curve ( float  speed ) const

protected

evaluate the understeer curve with a speed, taking *_x_scale into account

GDCLASS()

godot::CarPhysics::GDCLASS ( CarPhysics  , RigidBody3D    )

private

get_acceleration()

float godot::CarPhysics::get_acceleration

(

)

const

The base engine acceleration of this car.

get_brake()

bool godot::CarPhysics::get_brake

(

)

const

True if the hand-brake is currently active.

get_current_acceleration()

float godot::CarPhysics::get_current_acceleration ( ) const

protected

Returns acceleration, taking into account braking, throttle, and handbrake.

get_current_speed()

float godot::CarPhysics::get_current_speed

(

)

const

The current forward velocity (local_velocity.z)

get_current_steering()

float godot::CarPhysics::get_current_steering

(

)

const

The current steering input.

get_engine_brake_force()

float godot::CarPhysics::get_engine_brake_force

(

)

const

The base engine braking force of this car.

get_handbrake_force()

float godot::CarPhysics::get_handbrake_force

(

)

const

The amount of braking force applied by the handbrake.

get_handbrake_oversteer()

float godot::CarPhysics::get_handbrake_oversteer

(

)

const

The modifier applied to oversteering when the handbrake is active.

get_local_velocity()

Vector3 godot::CarPhysics::get_local_velocity

(

)

const

Public getter for current local velocity.

get_max_slide_speed()

float godot::CarPhysics::get_max_slide_speed

(

)

const

The maximum sideways speed that can be reached while drifting.

get_oversteer_brake_penalty()

float godot::CarPhysics::get_oversteer_brake_penalty

(

)

const

Modifier applied to brake force when oversteering.

get_oversteer_curve()

Ref< Curve > godot::CarPhysics::get_oversteer_curve

(

)

const

The base curve used for oversteering.

get_oversteer_curve_x_scale()

float godot::CarPhysics::get_oversteer_curve_x_scale

(

)

const

The amount of speed represented by x=1 on the oversteer curve.

get_oversteer_speed_penalty()

float godot::CarPhysics::get_oversteer_speed_penalty

(

)

const

Deceleration applied to forward speed when oversteering.

get_oversteer_steering_speed()

float godot::CarPhysics::get_oversteer_steering_speed

(

)

const

Base amount of steering applied while oversteering.

get_slide_resistance()

float godot::CarPhysics::get_slide_resistance

(

)

const

Deceleration applied to sideways velocity.

get_slide_speed_acceleration()

float godot::CarPhysics::get_slide_speed_acceleration

(

)

const

The sideways acceleration applied when drifting.

get_steering_inward_speed()

float godot::CarPhysics::get_steering_inward_speed

(

)

const

Target amount of velocity towards the centre of a turn while steering.

get_target_speed()

float godot::CarPhysics::get_target_speed

(

)

const

The target speed.

get_traction_recovery_speed()

float godot::CarPhysics::get_traction_recovery_speed

(

)

const

The speed at which the car will return to regular traction after under- or oversteering.

get_true_target_speed()

float godot::CarPhysics::get_true_target_speed ( ) const

protected

Returns the maximum speed modified by under/oversteer.

get_understeer_curve()

Ref< Curve > godot::CarPhysics::get_understeer_curve

(

)

const

The base curve used for understeering.

get_understeer_curve_x_scale()

float godot::CarPhysics::get_understeer_curve_x_scale

(

)

const

The amount of speed represented by x=1 on the understeer curve.

integrate_engine_acceleration()

void godot::CarPhysics::integrate_engine_acceleration ( PhysicsDirectBodyState3D *  state )

protected

Apply velocity along local z. Accelerates towards value returned by get_true_target_speed at get_current_acceleration m/s^2.

integrate_oversteer()

void godot::CarPhysics::integrate_oversteer ( PhysicsDirectBodyState3D *  state )

protected

Integrate oversteering to local_velocity to allow drifting.

integrate_steering()

void godot::CarPhysics::integrate_steering ( PhysicsDirectBodyState3D *  state )

protected

Integrate steering into angular and local x velocities. As a side-effect this also applies sliding resistance and sliding recovery. Also detects crashes to avoid glitchy behaviour when accelerating into a wall.

is_grounded()

bool godot::CarPhysics::is_grounded ( ) const

protected

Returns true if there is at least one contact with either of the wheels.

local_to_world_velocity()

Vector3 godot::CarPhysics::local_to_world_velocity

(

)

const

transform the current local_velocity to world coordinates

on_body_shape_entered()

void godot::CarPhysics::on_body_shape_entered ( RID  body_rid, Node *  node, int  body_shape_index, int  local_shape_index  )

protected

Detect that an object started colliding with the wheels.

on_body_shape_exited()

void godot::CarPhysics::on_body_shape_exited ( RID  body_rid, Node *  node, int  body_shape_index, int  local_shape_index  )

protected

Detect that an object lost contact with the wheels.

process_oversteer()

void godot::CarPhysics::process_oversteer

(

double

delta_time

)

Process the current_oversteer member variable.

process_understeer()

void godot::CarPhysics::process_understeer

(

double

delta_time

)

Process the current_understeer member variable.

set_acceleration()

void godot::CarPhysics::set_acceleration

(

float

value

)

The base engine acceleration of this car.

set_brake()

void godot::CarPhysics::set_brake

(

bool

value

)

True if the hand-brake is currently active.

set_current_steering()

void godot::CarPhysics::set_current_steering

(

float

steering

)

The current steering input.

set_engine_brake_force()

void godot::CarPhysics::set_engine_brake_force

(

float

value

)

The base engine braking force of this car.

set_handbrake_force()

void godot::CarPhysics::set_handbrake_force

(

float

value

)

The amount of braking force applied by the handbrake.

set_handbrake_oversteer()

void godot::CarPhysics::set_handbrake_oversteer

(

float

value

)

The modifier applied to oversteering when the handbrake is active.

set_max_slide_speed()

void godot::CarPhysics::set_max_slide_speed

(

float

value

)

The maximum sideways speed that can be reached while drifting.

set_oversteer_brake_penalty()

void godot::CarPhysics::set_oversteer_brake_penalty

(

float

value

)

Modifier applied to brake force when oversteering.

set_oversteer_curve()

void godot::CarPhysics::set_oversteer_curve

(

Ref< Curve >

curve

)

The base curve used for oversteering.

set_oversteer_curve_x_scale()

void godot::CarPhysics::set_oversteer_curve_x_scale

(

float

scale

)

The amount of speed represented by x=1 on the oversteer curve.

set_oversteer_speed_penalty()

void godot::CarPhysics::set_oversteer_speed_penalty

(

float

value

)

Deceleration applied to forward speed when oversteering.

set_oversteer_steering_speed()

void godot::CarPhysics::set_oversteer_steering_speed

(

float

value

)

Modifier applied to brake force when oversteering.

set_slide_resistance()

void godot::CarPhysics::set_slide_resistance

(

float

value

)

Deceleration applied to sideways velocity.

set_slide_speed_acceleration()

void godot::CarPhysics::set_slide_speed_acceleration

(

float

value

)

The sideways acceleration applied when drifting.

set_steering_inward_speed()

void godot::CarPhysics::set_steering_inward_speed

(

float

value

)

Target amount of velocity towards the centre of a turn while steering.

set_target_speed()

void godot::CarPhysics::set_target_speed

(

float

target

)

The target speed.

set_traction_recovery_speed()

void godot::CarPhysics::set_traction_recovery_speed

(

float

value

)

The speed at which the car will return to regular traction after under- or oversteering.

set_understeer_curve()

void godot::CarPhysics::set_understeer_curve

(

Ref< Curve >

curve

)

The base curve used for understeering.

set_understeer_curve_x_scale()

void godot::CarPhysics::set_understeer_curve_x_scale

(

float

scale

)

The amount of speed represented by x=1 on the understeer curve.

world_to_local_velocity()

Vector3 godot::CarPhysics::world_to_local_velocity

(

)

const

transform the current world velocity to local coordinates

Member Data Documentation

acceleration

float godot::CarPhysics::acceleration {20.f}

private

back_wheels

CollisionShape3D* godot::CarPhysics::back_wheels {nullptr}

private

brake

bool godot::CarPhysics::brake {false}

private

While true, the handbrake is on.

current_oversteer

float godot::CarPhysics::current_oversteer {0.f}

private

current_steering

float godot::CarPhysics::current_steering {0.f}

private

Current steering input.

current_understeer

float godot::CarPhysics::current_understeer {0.f}

private

engine_brake_force

float godot::CarPhysics::engine_brake_force {30.f}

private

front_wheels

CollisionShape3D* godot::CarPhysics::front_wheels {nullptr}

private

grounded_objects

HashSet<Node*> godot::CarPhysics::grounded_objects {}

private

handbrake_force

float godot::CarPhysics::handbrake_force {40.f}

private

handbrake_oversteer

float godot::CarPhysics::handbrake_oversteer {1.f}

private

last_velocity

Vector3 godot::CarPhysics::last_velocity {0.f, 0.f, 0.f}

private

Acceleration at the end of the integration step of the last frame.

local_velocity

Vector3 godot::CarPhysics::local_velocity {0.f, 0.f, 0.f}

private

Velocity relative to the local transform.

max_slide_speed

float godot::CarPhysics::max_slide_speed {20.f}

private

oversteer_brake_penalty

float godot::CarPhysics::oversteer_brake_penalty {0.25f}

private

oversteer_curve

Ref<Curve> godot::CarPhysics::oversteer_curve {}

private

oversteer_curve_x_scale

float godot::CarPhysics::oversteer_curve_x_scale {50.f}

private

oversteer_speed_penalty

float godot::CarPhysics::oversteer_speed_penalty {5.f}

private

oversteer_steering_speed

float godot::CarPhysics::oversteer_steering_speed {0.7f}

private

slide_resistance

float godot::CarPhysics::slide_resistance {20.f}

private

slide_speed_acceleration

float godot::CarPhysics::slide_speed_acceleration {0.05f}

private

steering_inward_speed

float godot::CarPhysics::steering_inward_speed {0.1f}

private

target_speed

float godot::CarPhysics::target_speed {0.f}

private

Target value for local_velocity.z.

traction_recovery_speed

float godot::CarPhysics::traction_recovery_speed {1.f}

private

understeer_curve

Ref<Curve> godot::CarPhysics::understeer_curve {}

private

understeer_curve_x_scale

float godot::CarPhysics::understeer_curve_x_scale {50.f}

private

understeer_speed_penalty

float godot::CarPhysics::understeer_speed_penalty {3.f}

private

---

The documentation for this class was generated from the following files:

• src/car_physics.hpp
• src/car_physics.cpp