Vehicles, Obstacles, Walls

Inheritance diagram of vehicle2d

Wall, Obstacle, Pointmass, and Vehicle classes.

  • BaseWall2d: Static, one-directional wall segments.

  • BasePointMass2d: Point mass with heading aligned to velocity.

  • SimpleObstacle2d: Immobile obstacle with center and bounding radius.

  • SimpleVehicle2d: BasePointMass2d with attached Navigator for steering.

  • SimpleRigidBody2d: (Experimental) mass with basic rotational physics.

Rendering is done independently of this module, but for convenience each class provides a set_spriteclass() class method. Once this is set, the constructors above will use the optional spritedata parameter to pass through rendering information to the sprite class.

class vehicle2d.BaseWall2d(center, length, thick, f_normal, spritedata=None)

A base class for static, wall-type obstacles.

Parameters

  • center (tuple or Point2d) – The center of the wall.

  • length (int) – Length of the wall in pixels.

  • thick (int) – Thickness of the wall in pixels.

  • f_normal (Point2d) – Normal vector out from the front of the wall.

  • spritedata (optional) – Extra data for rendering; see module notes.

Note

Walls are one-way due to the associated steering behaviours.

classmethod set_spriteclass(spriteclass)

Set the default sprite class used to render this type of object.

class vehicle2d.BasePointMass2d(position, velocity, radius, mass, maxspeed, maxforce, spritedata=None)

A moving object with rectilinear motion and optional sprite.

Parameters

  • position (Point2d) – Center of mass.

  • velocity (Point2d) – Velocity vector (initial facing is aligned to this).

  • radius (float) – Bounding radius of the object.

  • mass (float) – Total mass.

  • maxspeed (float) – Maximum speed.

  • maxforce (float) – Maximum force available per update.

  • spritedata (optional) – Extra data for rendering; see module notes.

This provides a minimal base class for a 2D pointmass with bounding radius and heading aligned to velocity. Use move() for rectilinear physics updates each cycle (including applying force).

classmethod set_spriteclass(spriteclass)

Set the default sprite class used to render this type of object.

accumulate_force(force_vector)

Add a new force to what’s already been accumulated.

Parameters

force_vector (Point2d) – Added to any previously-accumulated force.

This function is intended to allow multiple sources to exert force on an object without needing to compute those forces all at once. Use move() below with force_vector=None to apply the resultant force accumulated by this method and reset accumulated force to zero.

move(delta_t=1.0, force_vector=None)

Updates rectilinear position, velocity, and acceleration.

Parameters

  • delta_t (float) – Time increment since last move.

  • force_vector (Point2d, optional) – Vector force to apply during this update.

If force_vector is None (the default), we use the force accumulated by self.accumulate_force() since the last call to this method, and zero out the accumulated force. Otherwise, apply the force_vector given, and leave the accumulated force unaffected.

In any case, the maximum force and resulting velocity are limited by maxforce and maxspeed attributes.

class vehicle2d.SimpleObstacle2d(position, facing, radius, spritedata=None)

A static obstacle with center and bounding radius.

Parameters

  • position (Point2d) – Center of mass.

  • facing (Point2d) – Foward vector, used for rendering only.

  • radius (float) – Bounding radius of the object.

  • spritedata (optional) – Extra data for rendering; see module notes.

move(delta_t=1.0, force_vector=None)

Does nothing; SimpleObstacles are immovable.

class vehicle2d.SimpleVehicle2d(position, velocity, radius, mass, maxspeed, maxforce, spritedata=None)

Point mass with attached Navigator for steering behaviours.

Parameters

  • position (Point2d) – Center of mass.

  • velocity (Point2d) – Velocity vector (initial facing is aligned to this).

  • radius (float) – Bounding radius of the object.

  • mass (float) – Total mass.

  • maxspeed (float) – Maximum speed.

  • maxforce (float) – Maximum force available per update.

  • spritedata (optional) – Extra data for rendering; see module notes.

Use this class for basic steering.Navigator functionality. Calling move() will get the current steering force from the Navigator and apply it.

move(delta_t=1.0, force_vector=None)

Compute steering force (via Navigator); update rectilinear motion.

class vehicle2d.SimpleRigidBody2d(position, velocity, beta, omega, radius, mass, maxspeed, maxforce, inertia, maxomega, maxtorque, spritedata=None)

Moving object with linear and angular motion, with optional sprite.

Parameters

  • position (Point2d) – Center of mass.

  • velocity (Point2d) – Velocity vector.

  • beta (float) – Offset angle between heading/velocity and facing.

  • omega (float) – Angular speed.

  • radius (float) – Bounding radius of the object.

  • mass (float) – Total mass.

  • maxspeed (float) – Maximum speed.

  • maxforce (float) – Maximum force available per update.

  • inertia (float) – Rotational inertia.

  • maxomega (float) – Maximum magnitude of angular speed.

  • maxtorque (float) – Maximum magnitude of torque per update.

  • spritedata (optional) – Extra data for rendering; see module notes.

Warning

Still experimental!

move(delta_t=1.0, force_vector=None)

Updates position, velocity, and acceleration.

Parameters

  • delta_t (float) – Time increment since last move.

  • force_vector (Point2d, optional) – Constant force during this update.

Note

We must override BasePointMass2d.move() in order to avoid aligning our heading with forward velocity.

rotate(delta_t=1.0, torque=0)

Updates heading, angular velocity, and torque.

Parameters

  • delta_t (float) – Time increment since last rotate.

  • torque (float, optional) – Constant torque during this update.