o1.world
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A Bounds
represents the dimensions of a rectangular area in twodimensional space.
A Bounds
represents the dimensions of a rectangular area in twodimensional 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 toplevel package o1, so it’s accessible to students simply via import o1.*
.
Parameters
 height

the height of the
Bounds
(the distance from its top edge to its bottom edge)  left

the x coordinate of the left edge of the
Bounds
 top

the y coordinate of the top edge of the
Bounds
 width

the width of the
Bounds
(the distance from its left edge to its right edge)
Attributes
 Companion
 object
 Supertypes
A companion object for class Bounds
. Provides a factory method.
Each instance of this class represents a direction on a twodimensional 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.
Each instance of this class represents a direction on a twodimensional 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 nonzero 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 Direction
s 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)
andDirection.fromRadians(scala.math.Pi / 4)
.
Some of the methods of a Direction
object also create and return new Direction
s, 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 toplevel package o1, so it’s accessible to students simply via import o1.*
.
Parameters
 dx

the amount of change in the x coordinate when moving in this direction, relative to
dy
 dy

the amount of change in the y coordinate when moving in this direction, relative to
dx
Attributes
 Companion
 object
 Supertypes
This companion object of class Direction
provides some constants of type Direction
and methods for creating new Direction
instances.
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 toplevel package o1, so it’s accessible to students simply via import o1.*
.
Attributes
Each instance of this class represents a location on a twodimensional plane. A Pos
object is essentially a pair of two coordinates, x
and y
. Pos
objects are immutable.
Each instance of this class represents a location on a twodimensional 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 toplevel package o1, so it’s accessible to students simply via import o1.*
.
Parameters
 x

the x coordinate of the
Pos
 y

the y coordinate of the
Pos
Attributes
 Companion
 object
 Supertypes
This companion object of class Pos
provides alternative methods for creating new Pos
objects. It has an alias in the toplevel package o1, so it’s accessible to students simply via import o1._
.
Each instance of this class represents movement in the context of a twodimensional plane. A velocity is a combination of a Direction of movement with a speed (a nonnegative Double
).
Each instance of this class represents movement in the context of a twodimensional plane. A velocity is a combination of a Direction of movement with a speed (a nonnegative 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
anddy
, as inVelocity(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 toplevel package o1, so it’s accessible to students simply via import o1.*
.
Parameters
 direction

the direction of movement
 speed

the speed of movement; this cannot be negative
Attributes
 Companion
 object
 Supertypes
This companion object of class Velocity
exists primarily to provide convenience methods for creating new instances of Velocity
.
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 toplevel package o1, so it’s accessible to students simply via import o1.*
.