Polygon

class Polygon

a polygon Object.
Please do note that melonJS implements a simple Axis-Aligned Boxes collision algorithm, which requires all polygons used for collision to be convex with all vertices defined with clockwise winding. A polygon is convex when all line segments connecting two points in the interior do not cross any edge of the polygon (which means that all angles are less than 180 degrees), as described here below :

A polygon's `winding` is clockwise if its vertices (points) are declared turning to the right. The image above shows COUNTERCLOCKWISE winding.

Constructor

new Polygon(x: number, y: number, points: Array<Vector2d>) → {}

Parameters:
Name	Type	Attributes	Default	Description
x	number	<optional>	0	origin point of the Polygon
y	number	<optional>	0	origin point of the Polygon
points	Array<Vector2d>			array of vector defining the Polygon

Summary

Properties from Polygon

Array<Vector2d>

points

Vector2d

pos

string

type = "Polygon"

Methods from Polygon

Polygon	clone()
boolean	contains(x: number \| Vector2d, y: number)
Bounds	getBounds()
Array<number>	getIndices()
boolean	isConvex()
Polygon	recalc()
Polygon	rotate(angle: number, v: Vector2d \| ObservableVector2d)
Polygon	scale(x: number, y: number)
Polygon	scaleV(v: Vector2d)
Polygon	setShape(x: number, y: number, points: Array<Vector2d> \| Array<number>)
Polygon	setVertices(vertices: Array<Vector2d>)
	shift(x: number \| Vector2d, y: number)
Polygon	to2d()
Polygon	toIso()
Polygon	transform(m: Matrix2d)
Polygon	translate(x: number \| Vector2d, y: number)
Bounds	updateBounds()

Public Properties

points poly.js:26

points: Array<Vector2d>

Array<Vector2d>

Array of points defining the Polygon
Note: If you manually change points, you must call recalcafterwards so that the changes get applied correctly.

pos poly.js:20

pos: Vector2d

Vector2d

origin point of the Polygon

type poly.js:58

type: string = "Polygon"

string

the shape type (used internally)

Public Methods

clone poly.js:413

clone() → {Polygon}

clone this Polygon

Returns:
Type	Description
Polygon	new Polygon

contains poly.js:354

contains(x: number | Vector2d, y: number) → {boolean}

Returns true if the polygon contains the given point.
(Note: it is highly recommended to first do a hit test on the corresponding
bounding rect, as the function can be highly consuming with complex shapes)

if (polygon.contains(10, 10)) {
  // do something
}
// or
if (polygon.contains(myVector2d)) {
  // do something
}

Parameters:
Name	Type	Attributes	Description
x	number \| Vector2d		x coordinate or a vector point to check
y	number	<optional>	y coordinate

Returns:
Type	Description
boolean	True if the polygon contain the point, otherwise false

getBounds poly.js:389

getBounds() → {Bounds}

returns the bounding box for this shape, the smallest Rectangle object completely containing this shape.

Returns:
Type	Description
Bounds	this shape bounding box Rectangle object

getIndices poly.js:248

getIndices() → {Array<number>}

returns a list of indices for all triangles defined in this polygon

Returns:
Type	Description
Array<number>	an array of vertex indices for all triangles forming this polygon.

isConvex poly.js:259

isConvex() → {boolean}

Returns true if the vertices composing this polygon form a convex shape (vertices must be in clockwise order).

Returns:
Type	Description
boolean	true if the vertices are convex, false if not, null if not computable

recalc poly.js:197

recalc() → {Polygon}

Computes the calculated collision polygon. This must be called if the points array, angle, or offset is modified manually.

Returns:
Type	Description
Polygon	Reference to this object for method chaining

rotate poly.js:152

rotate(angle: number, v: Vector2d | ObservableVector2d) → {Polygon}

Rotate this Polygon (counter-clockwise) by the specified angle (in radians).

Parameters:
Name	Type	Attributes	Description
angle	number		The angle to rotate (in radians)
v	Vector2d \| ObservableVector2d	<optional>	an optional point to rotate around

Returns:
Type	Description
Polygon	Reference to this object for method chaining

scale poly.js:171

scale(x: number, y: number) → {Polygon}

Scale this Polygon by the given scalar.

Parameters:
Name	Type	Attributes	Default	Description
x	number
y	number	<optional>	x

Returns:
Type	Description
Polygon	Reference to this object for method chaining

scaleV poly.js:188

scaleV(v: Vector2d) → {Polygon}

Scale this Polygon by the given vector

Parameters:
Name	Type	Description
v	Vector2d

Returns:
Type	Description
Polygon	Reference to this object for method chaining

setShape poly.js:72

setShape(x: number, y: number, points: Array<Vector2d> | Array<number>) → {Polygon}

set new value to the Polygon

Parameters:
Name	Type	Description
x	number	position of the Polygon
y	number	position of the Polygon
points	Array<Vector2d> \| Array<number>	array of vector or vertice defining the Polygon

Returns:
Type	Description
Polygon	this instance for objecf chaining

setVertices poly.js:85

setVertices(vertices: Array<Vector2d>) → {Polygon}

set the vertices defining this Polygon

Parameters:
Name	Type	Description
vertices	Array<Vector2d>	array of vector or vertice defining the Polygon

Returns:
Type	Description
Polygon	this instance for objecf chaining

shift poly.js:329

shift(x: number | Vector2d, y: number) → {}

Shifts the Polygon to the given position vector.

polygon.shift(10, 10);
// or
polygon.shift(myVector2d);

Parameters:
Name	Type	Attributes	Description
x	number \| Vector2d		x coordinate or a vector point to shift to
y	number	<optional>

to2d poly.js:144

to2d() → {Polygon}

apply a 2d projection to this shapen

Returns:
Type	Description
Polygon	Reference to this object for method chaining

toIso poly.js:136

toIso() → {Polygon}

apply an isometric projection to this shape

Returns:
Type	Description
Polygon	Reference to this object for method chaining

transform poly.js:120

transform(m: Matrix2d) → {Polygon}

apply the given transformation matrix to this Polygon

Parameters:
Name	Type	Description
m	Matrix2d	the transformation matrix

Returns:
Type	Description
Polygon	Reference to this object for method chaining

translate poly.js:299

translate(x: number | Vector2d, y: number) → {Polygon}

translate the Polygon by the specified offset

polygon.translate(10, 10);
// or
polygon.translate(myVector2d);

Parameters:
Name	Type	Attributes	Description
x	number \| Vector2d		x offset or a vector point to translate by
y	number	<optional>	y offset

Returns:
Type	Description
Polygon	Reference to this object for method chaining

updateBounds poly.js:400

updateBounds() → {Bounds}

update the bounding box for this shape.

Returns:
Type	Description
Bounds	this shape bounding box Rectangle object