# Vector2

Vector2 is a vector in 2D space. A vector is a mathematical object that has direction and length, usually represented by an arrow. A Vector2 can also be represented by a pair of *(x,y)* coordinates.

In SurgeScript, vectors are immutable. Once created, you can't change their coordinates directly. In order to bring about change (say, in the position of an entity), you need to create a new vector.

Vector2 objects have been designed in such a way that their functions make them chainable. You can compose different vector operations using english-based terms, as in the example below:

*Example*

```
using SurgeEngine.Player;
using SurgeEngine.Vector2;
...
player = Player.active;
...
l = Vector2(6, 8).scaledBy(0.5).length; // number five
u = Vector2.right.rotatedBy(45).scaledBy(2); // a vector
v = player.transform.position.translatedBy(5,0); // a vector
...
```

*Note:* In Open Surge, the x-axis grows to the right of the screen and the y-axis grows downwards, as in many other 2D games and software.

## Factory

#### Vector2

`Vector2(x, y)`

Spawns a 2D vector with the given coordinates.

*Arguments*

`x`

: number. The x-coordinate of the vector.`y`

: number. The y-coordinate of the vector.

*Returns*

A Vector2 object.

*Example*

```
using SurgeEngine.Vector2;
using SurgeEngine.Player;
// This entity will lock the player on position (100, 100)
object "PlayerLocker" is "entity", "awake"
{
pos = Vector2(100, 100);
state "main"
{
player = Player.active;
player.transform.position = pos;
}
}
```

#### Vector2.up

`Vector2.up`

The unit up vector.

*Returns*

Returns the up vector of length 1.

#### Vector2.right

`Vector2.right`

The unit right vector.

*Returns*

Returns the right vector of length 1.

#### Vector2.down

`Vector2.down`

The unit down vector.

*Returns*

Returns the down vector of length 1.

#### Vector2.left

`Vector2.left`

The unit left vector.

*Returns*

Returns the left vector of length 1.

#### Vector2.zero

`Vector2.zero`

The zero vector.

*Returns*

Returns the (0,0) vector.

## Properties

#### x

`x`

: number, read-only.

The x-coordinate of the vector.

#### y

`y`

: number, read-only.

The y-coordinate of the vector.

#### length

`length`

: number, read-only.

The length of the vector.

#### angle

`angle`

: number, read-only.

The angle, in degrees, between the vector and the positive x-axis (as in polar coordinates).

## Functions

#### plus

`plus(v)`

Returns a Vector2 corresponding to the addition between `this`

and `v`

.

*Arguments*

`v`

: Vector2 object.

*Returns*

Returns a Vector2 object corresponding to the result of the operation.

*Example*

```
a = Vector2(3, 1);
b = Vector2(2, 1);
c = a.plus(b); // c = (5,2)
```

#### minus

`minus(v)`

Returns a Vector2 corresponding to the subtraction between `this`

and `v`

.

*Arguments*

`v`

: Vector2 object.

*Returns*

Returns a Vector2 object corresponding to the result of the operation.

*Example*

```
v = Vector2(5, 5);
zero = v.minus(v); // zero = (0,0)
```

#### dot

`dot(v)`

Returns the dot product between `this`

and `v`

.

*Arguments*

`v`

: Vector2 object.

*Returns*

Returns a number: the dot product between `this`

and `v`

.

#### normalized

`normalized()`

Returns a normalized copy of `this`

: the new vector will have length one.

*Returns*

Returns a Vector2 object corresponding to the result of the operation.

#### directionTo

`directionTo(v)`

Returns a unit vector pointing to `v`

(from `this`

).

*Arguments*

`v`

: Vector2 object.

*Returns*

Returns a Vector2 of length one corresponding to the result of the operation.

#### distanceTo

`distanceTo(v)`

Considering `this`

and `v`

as points in space, this function returns the distance between them.

*Arguments*

`v`

: Vector2 object.

*Returns*

Returns a number corresponding to the specified distance.

*Example*

```
using SurgeEngine.Transform;
using SurgeEngine.Player;
// This entity will show the distance between
// itself and the active player
object "DistanceDebugger" is "entity", "awake"
{
transform = Transform();
state "main"
{
player = Player.active;
playerpos = player.transform.position;
distance = transform.position.distanceTo(playerpos);
Console.print(distance);
}
}
```

#### translatedBy

`translatedBy(dx,dy)`

Returns a copy of `this`

translated by `(dx,dy)`

.

*Arguments*

`dx`

: number. The offset to be added to the x-coordinate.`dy`

: number. The offset to be added to the y-coordinate.

*Returns*

Returns a Vector2 object corresponding to the result of the operation.

*Example*

```
using SurgeEngine.Vector2;
...
one = Vector2(1,1);
v = one.translatedBy(4,5); // (5,6)
```

#### rotatedBy

`rotatedBy(deg)`

Returns a copy of `this`

rotated counterclockwise by `deg`

degrees.

*Arguments*

`deg`

: number. The amount of degrees used on the rotation.

*Returns*

Returns a Vector2 object corresponding to the result of the operation.

*Example*

```
using SurgeEngine.Vector2;
...
// A unit vector with an angle of 45 degrees
// (relative to the positive x-axis)
v = Vector2.right.rotatedBy(45);
```

*Note:* in Open Surge, the y-axis grows downwards. As an example, Vector2.right (1,0) rotated counterclockwise by 90 degrees will be the same as Vector2.up (0,-1). In addition, to rotate a Vector2 by `deg`

degrees clockwise you may rotate it by `-deg`

degrees counterclockwise.

#### scaledBy

`scaledBy(s)`

Returns a copy of `this`

scaled by `s`

. The length of the resulting vector will be the length of `this`

multiplied by `s`

.

*Arguments*

`s`

: number. The multiplier.

*Returns*

Returns a Vector2 object corresponding to the result of the operation.

*Example*

```
using SurgeEngine.Vector2;
...
one = Vector2(1,1);
two = one.scaledBy(2); // (2,2)
half = one.scaledBy(0.5); // (0.5,0.5)
```

#### projectedOn

`projectedOn(v)`

Returns a copy of `this`

projected on nonzero vector `v`

.

*Arguments*

`v`

: Vector2 object.

*Returns*

Returns a Vector2 object corresponding to the result of the operation.

#### toString

`toString()`

Converts the vector to a string.

*Returns*

Returns a string containing the coordinates of `this`

.

*Example*

```
using SurgeEngine.Vector2;
...
one = Vector2(1,1);
Console.print(one); // using toString() implicitly
```