Info

Collision is a python library that is meant for collision detection between convex and concave polygons, circles, and points.

Installation

To get the latest stable version:

pip install collision

To get the latest development version run:

pip install https://github.com/qwertyquerty/collision/archive/master.zip

Classes

class collision.Vector(x, y)

A 2D vector/point class

Properties:

• x (int) or (float) - The x-coordinate
• y (int) or (float) - The y-coordinate

Methods:

func copy() → collision.vec

Return a copy of the vector

func set(v)

Copy another vector's values onto the target vector

• v (collision.vec) - The vector to copy from

func perp() → collision.vec

Return the vector rotated perpendicularly

func rotate(angle) → collision.vec

Return the vector rotated to the angle

• angle (int) or (float) - Radians to rotate the point

func reverse() → collision.vec

Return a reversed version of the vector

func normalize() → collision.vec

Return a normalized version of the vector

func project(v) → collision.vec

Return the vector projected onto the passed vector

• v (collision.vec) - The vector to project upon

func project_n(v) → collision.vec

Return the vector projected onto a unit vector

• v (collision.vec) - The vector to project upon

func reflect(axis) → collision.vec

Return the vector reflected upon the passed axis vector

• axis (collision.vec) - The axis to reflect upon

func reflect_n(axis) → collision.vec

Return the vector reflected upon the passed axis unit vector

• axis (collision.vec) - The axis to reflect upon

func dot(v) → int or float

Returns the dot product of the vector and another

• v (collision.vec) - The other vector for the dot product

func ln() → int or float

Returns the length of the vector

func ln2() → int or float

Returns the squared length of the vector

---

class collision.Circle(pos, radius)

A simple circle with a position and radius

Properties:

• pos (collision.vec) - The center coordinate of the circle
• radius (int) or (float) - The radius of the circle
• aabb (tuple(tuple(int or float)) - The axis alligned bounding box of the circle

class collision.Poly(pos, points, angle = 0)

A convex polygon with a position, a list of points relative to that position, and an angle

Properties:

• pos (collision.vec) - The center coordinate of the circle
• points (list[collision.vec]) - A list of absolute points (each relative point + the position of the polygon.) Can not be directly edited.
• rel_points (list[collision.vec]) - A list of points relative to the position. This property should not be directly changed.
• angle (int) or (float) - The angle which the polygon is rotated. Changing this will cause the polygon to be recalculated.
• aabb (tuple(tuple(int or float)) - The axis-aligned bounding box of the Poly

Class Methods:

func Poly.from_box(pos, width, height) → collision.Poly

Creates a polygon from

• pos (collision.vec) - The center coordinate of the polygon/box
• width (int) or (float) - The width of the box
• height (int) or (float) - The height of the box

Methods:

func set_points(points)

Change the base points relative to the position. After this is done, the polygon will be recalculated again. The angle will be preserved. Use this instead of editing the points property.

func get_centroid() → collision.vec

Get the centroid of the polygon. Arithmetic means all of the points.

---

class collision.Concave_Poly(pos, points, angle = 0)

A concave polygon with a position, a list of points relative to that position, and an angle. This takes longer to collide than a regular Poly does, so only use this, if your shape must be concave.

Properties:

• pos (collision.vec) - The center coordinate of the circle
• points (list[collision.vec]) - A list of absolute points (each relative point + the position of the polygon.) Can not be directly edited.
• rel_points (list[collision.vec]) - A list of points relative to the position. This property should not be directly changed.
• tris (list[collision.Poly]) - A list of triangles relative to the position on the poly that makes up the concave polygon is used for concave collisions.
• angle (int) or (float) - The angle which the polygon is rotated. Changing this will cause the polygon to be recalculated.
• aabb (tuple(tuple(int or float)) - The axis alligned bounding box of the Poly

Methods:

func set_points(points)

Change the base points relative to the position. After this is done, the polygon will be recalculated again. The angle will be preserved. Use this instead of editing the points property.

func get_centroid() → collision.vec

Get the centroid of the polygon. Arithmetic means all of the points.

---

class collision.Response()

The result of a collision between two objects. It may optionally be passed to collision tests to retrieve additional information. At its cleared state, it may seem to have odd values. Ignore these, they are just there to make generating the response more efficient. The response should be ignored unless there is a successful collision.

Properties:

• a (collision shape) - The first object in the collision test
• b (collision shape) - The second object in the collision test
• overlap (int) or (float) - Magnitude of the overlap on the shortest colliding axis
• overlap_n (collision.vec) - The shortest colliding axis (unit vector)
• overlap_v (collision.vec) - The overlap vector. If this is subtracted from the position of a, a and b will no longer be colliding.
• a_in_b (bool) - Whether a is fully inside of b
• b_in_a (bool) - Whether b is fully inside of a

Methods:

func reset() → collision.Response

Reset the Response for re-use, and returns itself

Collisions

func collision.collide(a, b, response = None) → bool

Test two shapes against each other. If a response is passed, and there is a collision, that response will be updated to the response values. The response will not be generated if there is no collision and it will be at its default values. Concave polys currently do not support responses.

• a (collision shape) - The first shape to test
• b (collision shape) - The second shape to test
• response (collision.Response) - Optional response that will be updated if there's a collision.

func collision.test_aabb(a, b) → bool

Test two axis-aligned bounding boxes against each other. This is already done in collision.collide so there's no need for you to do it for optimization.

• a (tuple(tuple(int or float))) The first AABB
• b (tuple(tuple(int or float))) The second AABB