Physics module¶
Physics contains the objects relating to mathematical calculations, such as Vectors, Forces, and PhysicsObjects. There are no UI components in this module.
All displacements are calculated on an abstract plane - Ui.PhysicsCanvas is responsible for translating to
canvas coordinates.
One semi-exception - PhysicsObjects handle their own collision detection, and they do that by referencing the collection of PhysicsObjects in PhysicsCanvas.
All the physics logic and calculation should be handled here.
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class
Physics.Force(angle, magnitude, duration=1.0, constant=False)[source]¶ Bases:
Physics.VectorA force which operates over time, executing a single force on the object once per sec.
If constant is true, the force does not deplete and will continue acting on the object.
PhysicsObjects have lists of forces currently operating on them. As the PhysicsObject updates, it gets a Vector representing a force for each force acting on it. That force is scaled based on the time of the update interval. It also reduces the ‘remaining’ attribute of the Force until the Force is depleted.
- Parameters
angle (number) – Angle in radians
magnitude (number) – Magnitude in Newtons (per second)
duration (number) – Seconds force is exerted for
constant (bool) – Whether force depletes or not
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static
make_directional_force(direction, magnitude, duration=1.0, constant=False)[source]¶ Similar to Vector.make_directional_vector, creates a force in a cardinal direction.
- Parameters
direction (str) – N,S,E,W,NE,SE,NW,SW
magnitude (number) – In Newtons
duration (number) – In seconds
constant (boolean) – Whether force depletes
- Returns
A new force
- Return type
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update(interval)[source]¶ Scales the current vector magnitude to the interval, so that self.force_magnitude is delivered each second; if updates occur more frequently than once a second, this causes this forces temporary magnitude to be lower to account for that.
- Parameters
interval (number) – Time since last update, in seconds.
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class
Physics.PhysicsObject(material, mass)[source]¶ Bases:
objectAn object which has vectors for acceleration, velocity, and displacement.
Abstracts the physics calculations -
Ui.PhysicsCanvasis responsible for the rendering, and translating the displacement of the PhysicsObject into the Tkinter Canvas coordinate space.Each update, it determines how much force should be applied based on the interval and the list of forces currently affecting this object.
From the net force and mass, it calculates acceleration. From the acceleration, it calculates velocity. From velocity, displacement is calculated.
\(F_{net} = \sum{F}\text{ Newtons}\)
\(a = \frac{F_\text{net}}{m}\text{ m/s}^2\)
\(v = at + v_0 \text{ m/s}\)
\(s = vt + s_0 = \frac{1}{2}at^2+v_0t+s_0 \text{ m}\)
- Parameters
material (
Substance.Material) – The material fromSubstance.Materialused in this object. Determines its color and size based on the material density.mass (Number) – The mass of the object. (kg)
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acceleration¶ A vector of acceleration magnitude and angle
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canvas_id¶ Used by the tkinter canvas to reference the shape linked to this object
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check_collision(interval)[source]¶ The way collision is checked is that the next displacement from the velocity is calculated.
For each other extant physics object on the canvas, the next displacement from velocity is calculated.
If the lines between the displacements cross, the vectors have ‘collided’.
This function returns True or False and is used in the update function. If collision doesn’t happen, the update function handles simple movement.
- Parameters
interval –
- Returns
Whether collision happened
- Return type
bool
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clear_forces()[source]¶ Clears forces from self.dependent_force_generators by calling remove() on each
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collide(other_object, my_next_displacement, other_next_displacement, interval)[source]¶ Called by the check_collision function. Next displacements calculated there are passed as parameters to avoid redundant calculations.
The elastic collision formulas:
link - https://imada.sdu.dk/~rolf/Edu/DM815/E10/2dcollisions.pdf
- Parameters
other_object (ForceObject) – The colliding object
my_next_displacement (Vector) – Displacement vector that would realize if no collision
other_next_displacement (Vector) – Displacement vector for other object that would realize if no collision
interval (number) – Interval of distance move, second(s)
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dependent_force_generators¶ Force generators like
Physics.GravitationalForceGenerator
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displacement¶ A vector of positional offset from the 0,0 of world origin
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forces¶ Currently active forces affecting this object
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height¶ height in m
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mass¶ mass in kg
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material¶ The material the PhysicsObject is made of
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physics_canvas¶ Reference to canvas added when object rendered on canvas
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side¶ Length of a side in m
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update(interval)[source]¶ Gets a new vector equal to multiplying acceleration by Velocity and adds it to the velocity, mutating the velocity vector. \(v = at + v_0\) Does the same for displacement. \(s = vt + s_0\) Tells physicsCanvas to move the rendering of the oval.
- Parameters
interval (number) – The time since last update.
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velocity¶ A vector of velocity magnitude and angle
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width¶ width in m
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class
Physics.Vector(angle, magnitude)[source]¶ Bases:
objectRepresents direction and magnitude. Vectors can be broken into x and y components and reassembled from those components.
- Parameters
angle (number) – The angle, in radians
magnitude (number) – The magnitude of the Vector
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add(other_vector)[source]¶ Use this to MUTATE this Vector by adding another Vector to it.
The other Vector will be unchanged.
- Parameters
other_vector (Vector) – A vector to add to this one.
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add_make(other_vector)[source]¶ Use this to have a new vector return from the addition and the input vectors to be unchanged.
No existing Vector will mutate.
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calculate_angles()[source]¶ Calculates angle and mag from components.
\(\theta= \arctan{(\frac{y}{x})}\)
\(\text{mag} = \sqrt{x^2+y^2}\)
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calculate_components()[source]¶ Calculates components from angle and magnitude.
\(y = \text{vector}_\text{mag} * \sin{\theta}\)
\(x = \text{vector}_\text{mag} * \cos{\theta}\)
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dot_product(other_vector)[source]¶ Gets the scalar dot product of this and another vector Non mutating
- Parameters
other_vector – A vector to multiply with this one
- Returns
A scalar
- Return type
number
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static
make_directional_vector(direction='S', magnitude=1)[source]¶ Static method which creates a directional Vector from compass coordinates passed as a character.
Direction string controls vector angle. I.e.: ‘E’: 0 radians (0 degrees) ‘W’: 3.1415 radians (180 degrees)
Valid directions are e,ne,n,nw,w,sw,s,se
- Parameters
direction (str) – character for direction
magnitude (number) – vector magnitude
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static
make_vector_from_components(x, y)[source]¶ Static: Create a new Vector from x and y values. :param x: The x component :type x: number :param y: The y component :type y: number :returns: A brand new Vector :rtype: Vector
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normal_make()[source]¶ Returns a new magnitude 1 vector in the same angle.
- Returns
new Vector
- Return type
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rotate(radians)[source]¶ Mutates this Vector by adding radians to its angle and recalculating its components.
- Parameters
radians (number) – Radians to add to this Vector’s angle.
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scale(scalar)[source]¶ Mutates this Vector by multiplying its magnitude by the scalar.
- Parameters
scalar (number) – Scalar to multiply this Vector’s angle by.
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scale_make(scalar)[source]¶ Creates a new Vector of a magnitude equal to this Vector’s magnitude multiplied by the scalar, and returns the new Vector..
- Parameters
scalar (number) – Scalar to multiply this Vector’s angle by.
- Returns
A brand new Vector
- Return type