nape.geom.Vec2

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nape.geom.Vec2 class

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Package	nape.geom
Class	Vec2

2D Vector class.

Note: In many cases a Vec2 will be returned from a function internal to nape and will be marked internally as an 'immutable' Vec2. This is documented in those cases; trying to modify (mutate) such a Vec2 will result in an error.

Trying to use a disposed Vec2 will also result in an error, the pool works in a FILO order so as to make catching the use of a disposed Vec2 bug easier

Weak Vec2's are so-named because when given to any nape function, they will be automaticaly disposed of afterwards (Makes re-using Vec2's very easy, but be careful :P). Occasionaly it is the case that this will not occur, in which case it will be noted. The main exception is with lists, pushing a weak Vec2 to a list does not dispose it, but instead adds it as usual to the list. Then for example the Polygon constructor which takes a list of Vec2, any weak Vec2's in this list will be disposed of and removed from the list.

Public Properties

	Property	Defined By
	x : Float x value	Vec2
	y : Float y value	Vec2
	length : Float length	Vec2
	angle : Float angle	Vec2

	Constructor
	new(?x:Float=0, ?y:Float=0) Construct a new vector. Use of 'get' is preferred.

	Method	Defined By
	dispose() Release vector to the object pool.	Vec2
	const lsq() : Float Squared length of vector.	Vec2

	set(p:const Vec2) : Vec2 Set values from vector	Vec2
	setxy(x:Float, y:Float) : Vec2 Set values from coordinate pair	Vec2
	rotate(angle:Float) : Vec2 Rotate vector in-place	Vec2

	const copy(?weak:Bool=false) : Vec2 Produce a copy of this vector.	Vec2

	const dot(a:const Vec2) : Float Compute dot product.	Vec2
	const cross(a:const Vec2) : Float Compute cross product.	Vec2

	const add(a:const Vec2, ?weak:Bool=false) : Vec2 Add vectors together	Vec2
	const sub(a:const Vec2, ?weak:Bool=false) : Vec2 Subtract vectors together	Vec2
	const mul(s:Float, ?weak:Bool=false) : Vec2 Multiply vector by scalar	Vec2
	addeq(a:const Vec2) : Vec2 Add vector accumulatively	Vec2
	subeq(a:const Vec2) : Vec2 Subtract vector accumulatively	Vec2
	muleq(s:Float) : Vec2 Multiply vector by scalar	Vec2

Public Static Methods

	Method	Defined By
	static get(?x:Float=0, ?y:Float=0, ?weak:Bool=false) : Vec2 Allocate a vector from the object pool; or failing that, construct a new one.	Vec2
	static weak(?x:Float=0, ?y:Float=0) : Vec2 Allocate a 'weak' vector from the object pool; or failing that, construct a new one.	Vec2
	static fromPoint(point:const flash.geom.Point, ?weak:Bool=false) : Vec2 (flash9+) Constructor vector from Point.	Vec2
	static fromPolar(length:Float, angle:Float, ?weak:Bool=false) : Vec2 Construct Vec2 from polar coordinates.	Vec2

Property Detail

property x : Float

x coordinate of vector.

Error on setter if:

Vec2 is immutable

property y : Float

y coordinate of vector.

Error on setter if:

Vec2 is immutable

property length : Float

length of vector.

Error on setter if:

Vec2 is immutable

property angle : Float

angle of vector as measured counterclockwise from +x axis in radians.

Error on setter if:

Vec2 is immutable

Constructor Detail

function new(?x:Float=0, ?y:Float=0)

Construct a new vector from given cartesian values. Using the static get method is preferred as it will make use of any released Vec2's in the object pool whereas the constructor will allocate a new Vec2 from the heap whether there is anything in the object pool or not.

function dispose()

Releases the vector to the object pool leaving it available for re-use by the static 'get' method and nape internals. when disposing a Vec2 you should treat it the same as if you were wanting it to be collected by the garbage collector and have no remaining references to it; this isn't necessary but if you accidentaly use a released Vec2 and it is not caught (by debug mode errors) then incorrect behaviour may result

const function lsq() : Float

Computes squared length of vector.

function set(p:const Vec2) : Vec2

Copies values from given vector to this, returning the this vector.

Error if:

Vec2 is immutable

function setxy(x:Float, y:Float) : Vec2

Assigns values of this vector from arguments, returning the this vector.

Error if:

Vec2 is immutable

function rotate(angle:Float) : Vec2

Rotate the vector in-place returning the 'this' vector for chaining

Error if:

Vec2 is immutable

const function copy(?weak:Bool=false) : Vec2

Produce a copy of this vector.
(Note: the copy of an immutable vector will now be mutable).

const function dot(a:const Vec2) : Float

Computes dot product of the this vector and the given argument.

const function cross(a:const Vec2) : Float

Computes the cross product between the this vector and given argument. Strictly speaking the cross product is not defined on 2D vectors; this is defined as the perp-dot product chosen to be the z-coordinate in the 3D cross product between the equivalent 3D vectors, or equivalently the determinant of the direct product. This satifies all the normal rules of the cross product that apply.

const function add(a:const Vec2, ?weak:Bool=false) : Vec2

Adds the given vector to this returning the result.

const function sub(a:const Vec2, ?weak:Bool=false) : Vec2

Subtracts the given vector to this returning the result.

const function mul(s:Float, ?weak:Bool=false) : Vec2

Multiplies the vector by given scalar returning the result.

function addeq(a:const Vec2) : Vec2

Adds the given vector to this, modifying the this vector and returning the this vector. Equivalent to this.set(this.add(a))

Error if:

Vec2 is immutable

function subeq(a:const Vec2) : Vec2

Subtracts the given vector from this, modifying the this vector and returning the this vector. Equivalent to this.set(this.sub(a))

Error if:

Vec2 is immutable

function muleq(s:Float) : Vec2

Multiplies the vector by given scalar modifying the this vector and returning the this vector. Equivalent to this.set(this.mul(s))

Error if:

Vec2 is immutable

Static Method Detail

static function get(?x:Float=0, ?y:Float=0, ?weak:Bool=false) : Vec2

Allocates a vector with given cartesian values from the object pool. If the object pool is empty then a new vector will be constructed instead. Use of this method is preferable to using the constructor.

static function weak(?x:Float=0, ?y:Float=0) : Vec2

Allocates a 'weak' vector with given cartesian values from the object pool. If the object pool is empty then a new vector will be constructed instead. Use of this method is preferable to using the constructor.

static function fromPoint(point:const flash.geom.Point, ?weak:Bool=false) : Vec2

Only available for flash9+ targets; construct Vec2 from Point object.

static function fromPolar(length:Float, angle:Float, ?weak:Bool=false) : Vec2

Construct new vector from polar coordinates.