Particle module

For the purposes of this simulator, particles are objects which are rendered, and may behave in interesting ways, but do not have mass like ForceObjects and only remain on the screen for a limited duration.

They can be used to draw debug lines, add some kind of effect, or so forth.

They are updated by the PhysicsCanvas, which they add themselves to.

To make a new particle, just extend the Particle.Particle and overwrite the draw and transform methods.

There is no need to override the update and add_to methods.

To use a particle, initialize it, set its displacement to a vector, then call add_to(physicsCanvas)

class Particle.Line(duration, vector, color='#55443C', width=1, arrow='last')

Bases: Particle.Particle

Draws a Line on the canvas from a vector.

Only required params are duration and vector.

Parameters

• duration (number) – How long to stay on screen (seconds)

• vector (Physics.Vector) – A vector to calculate the line from

• color (str) – Color of the line, default is gray-purple

• width (int) – Width of line, default is 1

draw()

Draws Particle on the physics canvas.

Overwrite this method on inheriting particles.

transform(interval)

Called by update. Changes the particle in some way, i.e. movement, scale, etc.

Overwrite this method on inheriting particles

Parameters

interval (number) – interval, seconds

class Particle.Particle(duration=1)

Bases: object

The base particle class.

By default, for debug purposes, just shows a square at the origin that moves SE

Parameters

duration (number) – The time to display the particle (s)

add_to(physics_canvas)

Adds this Particle to the physics canvas, appending it to the list of particles to be updated and making the internal reference of self.physics_canvas.

Afterwards, calls self.draw

No need to overwrite this in extending classes; overwrite self.draw instead.

Parameters

physics_canvas –

Returns

canvas_id

Id for moving on canvas

displacement

Vector from physicsCanvas origin that particle will be placed

draw()

Draws Particle on the physics canvas.

Overwrite this method on inheriting particles.

physics_canvas

Particle gets a reference to PhysicsCanvas at the time add_to is called.

time_remaining

How much time the particle has left before it’s removed from the rendered/referenced objects

transform(interval)

Called by update. Changes the particle in some way, i.e. movement, scale, etc.

Overwrite this method on inheriting particles

Parameters

interval (number) – interval, seconds

update(interval)

Checks to see if there is time_remaining. If so, calls self.transform. Otherwise, removes references.

No need to overwrite this in extending classes; overwrite self.transform instead.

Parameters

interval (number) – Time since last update, seconds.

class Particle.Triangle(duration, x1, y1, x2, y2, x3, y3, color='blue')

Bases: Particle.Particle

Probably can remove this - didn’t wind up using

draw()

Draws Particle on the physics canvas.

Overwrite this method on inheriting particles.

transform(interval)

Called by update. Changes the particle in some way, i.e. movement, scale, etc.

Overwrite this method on inheriting particles

Parameters

interval (number) – interval, seconds