Geometry

Points

Similarly to how vectors work, points follow the immutability concept. By default a Point is immutable unless converted to a mutable version.

Immutable point:

val point = Point(1f, 5f)

Mutable point:

val point = MutablePoint(1f, 5f)
point.x = 3f

Angles

Instead of having to remember when to convert to and from degrees and radians, we can use the Angle value class. The Angle class offers converting to and from degrees and radians, the cos, sin, and tan values very easily as well as other mathmatical functions to make dealing with angles and rotations very easily.

By default, wherever LittleKt expects some sort of rotation or angle, it will expect an Angle type.

Creating Angles

We can directly set it to zero with the following:

val rotation = Angle.ZERO

or we can convert from either radians or degrees to an Angle:

val rotation: Angle = 90.degrees // converts from degrees to an Angle
val rotation2: Angle = (1.5708).radians // converts from radians to an Angle

If we want to convert from an Angle to either degrees or radians:

val rotation: Angle = 90.degrees
val rotation2: Angle = (1.5708).radians

val degrees: Float = rotation2.degrees // converts from an Angle to degrees
val radians: Float = rotation.radians // converts from an Angle to radians

Bresenham

There are two implementations of a the Bresenham’s line algorithm that casts out rays with a custom collider method that can be passed in. This can be found in the bresenham class.

We can cast a ray from one point to another with our own pass logic. Note: This implementation will be able to pass through diagonal points.

val pass = castRay(0, 0, 5, 5) {x, y ->
    return !hasCollision(x, y) // our own collision logic
}
if (pass) {
    // the ray passes from point a to point b successfully!
} else {
    // the ray failed to pass fully!
}

If we want to ensure that the ray cannot pass through diagonal points we can use the castThickRay method instead:

val pass = castThickRay(0, 0, 5, 5) {x, y ->
    return !hasCollision(x, y) // our own collision logic
}
if (pass) {
    // the ray passes from point a to point b successfully!
} else {
    // the ray failed to pass fully!
}