o1.world

A Bounds represents the dimensions of a rectangular area in two-dimensional space.

Bounds objects are immutable. They assume a space in which x coordinates increase rightwards and y coordinates downwards.

This class has an alias in the top-level package o1, so it’s accessible to students simply via import o1.*.

A companion object for class Bounds. Provides a factory method.

Each instance of this class represents a direction on a two-dimensional plane. A direction consists of two components: dx and dy, each of which is a number between -1.0 and +1.0 (inclusive). dx indicates the degree to which the x coordinate changes when moving in that direction; dy is the same for the y coordinate. The x coordinate increases rightwards and y downwards.

For example, moving straight rightwards can be thought of a moving in a Direction with a dx of +1.0 and a dy of 0.0; by comparison, the upward direction would have a dx of 0.0 and a dy of -1.0. . Diagonals have non-zero values for both dx and dy.

The dx and dy of any Direction always sum up to (roughly) 1.0, with the exception of the special value NoDirection which represents the lack of a direction and as zero for both components. (In this, a Direction is different than a Velocity, which is a combination of a direction of movement and a speed.)

You don’t instantiate Direction directly; instead, you create Directions with the methods on this class’s companion object. Among other things, you can:

• construct a direction from two differences between coordinates, as in Direction.fromDeltas(-100, 50); or
• create a direction that corresponds to a given angle, as in Direction.fromDegrees(60) and Direction.fromRadians(-scala.math.Pi / 4).

Some of the methods of a Direction object also create and return new Directions, as does the directionOf method on Pos objects. Moreover, this class’s companion object has a few predefined Direction constants: Up Down, Left, Right, and NoDirection.

Direction objects are immutable.

This class has an alias in the top-level package o1, so it’s accessible to students simply via import o1.*.

This companion object of class Direction provides some constants of type Direction and methods for creating new Direction instances.

The object has an alias in the top-level package o1, so it’s accessible to students simply via import o1.*.

Each instance of this class represents a location on a two-dimensional plane. A Pos object is essentially a pair of two coordinates, x and y. Pos objects are immutable.

This class has an alias in the top-level package o1, so it’s accessible to students simply via import o1.*.

This companion object of class Pos provides alternative methods for creating new Pos objects. It has an alias in the top-level package o1, so it’s accessible to students simply via import o1._.

Each instance of this class represents movement in the context of a two-dimensional plane. A velocity is a combination of a Direction of movement with a speed (a non-negative Double).

Another way to think about a Velocity is to divide it in two components: dx and dy. dx indicates the amount (and direction) of movement along the x axis; dy is the same for the y axis. The x coordinate increases rightwards and y downwards. For instance, a velocity with a dx of 10 and a dy of zero indicates rightward movement, and a velocity with a dx of -100 and a dy of -100 indicates faster movement leftwards and upwards.

There are many ways to create a Velocity using the methods on the companion object. Among other things, you can:

• construct a velocity from a direction and a (positive or zero) speed, as in Velocity(Direction.Left, 50);
• construct a direction from dx and dy, as in Velocity(-100, 50); or
• determine the velocity needed to go from one Pos to another in a single unit of time, as in Velocity.between(pos1, pos2).

Many of the methods on Velocity objects also create and return new velocities.

Velocity objects are immutable.

This class has an alias in the top-level package o1, so it’s accessible to students simply via import o1.*.

This companion object of class Velocity exists primarily to provide convenience methods for creating new instances of Velocity.

The object has an alias in the top-level package o1, so it’s accessible to students simply via import o1.*.