Class Polygon2

Defined in: lina.js.

Class Summary
Constructor Attributes	Constructor Name and Description
	Polygon2(xyList) Create a new 2d polygon.

Method Summary
Method Attributes	Method Name and Description
	append(ptOrPg) Append a point or polygon.
	appendUnique(ptOrPg, eps) Append a point or polygon, discarding duplicate points.
	area() Return polygons area.
	contains(pt) Check, if pt is inside this polygon.
	copy() Create and return a copy of this polygon.
	count() Return number of points.
	getBoundingBox(forceRecalc) Return the bounding box as {min: {x:_,y:_}, max: {x:_,y:_}}.
	getBoundingCircle() Return the smallest bounding circle.
	getConvexHull() Return a new polygon that connects the extreme points of this polygon.
	getPoint(idx) Return polygon point by index.
	getSegment(idx) Return polygon edge by index.
	getShapePolygon() Return a new polygon that draws along the outer lines of this polygon.
	getUniquePoints(eps) Return a copy with duplicate points removed.
	getXY(idx) Return polygon point by index.
	indexOfLowestPoint() Find index of point with minimmum y coord (and minimum x, if multiple matches found).
	intersects(pg2, velocity, time) Check, if this polygon intersects with another polygon.
	intersectsCircle(circle, velocity, time) Check, if this polygon intersects with a (moving) circle.
	isCCW() Check, if this polygon has a counterclocwise vertex order.
	makeCCW() Make sure this polygon has a counterclocwise vertex order.
	makeCW() Make sure this polygon has a clocwise vertex order.
	makeFirst(idx) Reorder polygon to start with given index.
	nearestPt(pt, cullingVector) Return polygon point nearest to pt.
	perimeter(closed) Return the total length of all line segments.
	remove(idx) Remove point at index.
	revert() Revert vertex list (in-place) and return this instance.
<static>	Polygon2.revert(pg) Return a reverse copy of a polygon.
	segmentIntersects(pt1, pt2) Check, if line segment pt1, pt2 is inside this polygon.
	set(xyList)
	setCount(n) Set maximum number of points (truncating trailing points).
	swap(idx, idx2) Exchange points.
	toString(prec) Return string representation '[(x1,y1), (x2,y2), .
<static>	Polygon2.transform(pg, m) Return a transformed copy of a polygon.
	transform(m) Apply transformation matrix (in-place) and return this instance.

Class Detail

Polygon2(xyList)

Create a new 2d polygon.

Parameters:
{Polygon2|float[]} xyList

Method Detail

append(ptOrPg)

Append a point or polygon.

Parameters:
{Point2|Polygon2|float[]} ptOrPg

Returns:: this

appendUnique(ptOrPg, eps)

Append a point or polygon, discarding duplicate points.

Parameters:
{Point2|Polygon2|float[]} ptOrPg
{float} eps: (optional) defaults to LinaJS.EPS

Returns:: this

area()

Return polygons area. This assumes an implicitly closed, non self-intersecting polygon.

contains(pt)

Check, if pt is inside this polygon.

Parameters:
pt

copy()

Create and return a copy of this polygon.

count()

Return number of points.

getBoundingBox(forceRecalc)

Return the bounding box as {min: {x:_,y:_}, max: {x:_,y:_}}.

Parameters:
forceRecalc

getBoundingCircle()

Return the smallest bounding circle.

getConvexHull()

Return a new polygon that connects the extreme points of this polygon. The result will be convex, non-intersecting. This bounding polygon has typically less points, and my be used for faster collision testing. This polygon is treated as unconnected point cloud, so it is possible to get a bounding polygon of multiple objects like this:

var pgHull = pg1.copy().append(pg2).append(pg3).getConvexHull();

getPoint(idx)

Return polygon point by index.

Parameters:
{int} idx

Returns:: Point2

{x0:_|y0:_|x1:_|y1:_} getSegment(idx)

Return polygon edge by index. If idx == last then the closing edge is returned.

Parameters:
{int} idx: Index of first point

Returns:: {x0:_|y0:_|x1:_|y1:_}

getShapePolygon()

Return a new polygon that draws along the outer lines of this polygon.

getUniquePoints(eps)

Return a copy with duplicate points removed.

Parameters:
{float} eps: (optional) defaults to LinaJS.EPS

Returns:: new Polygon2

{x:_|y:_} getXY(idx)

Return polygon point by index.

Parameters:
{int} idx

Returns:: {x:_|y:_}

indexOfLowestPoint()

Find index of point with minimmum y coord (and minimum x, if multiple matches found).

intersects(pg2, velocity, time)

Check, if this polygon intersects with another polygon.

Parameters:
pg2
velocity
time

intersectsCircle(circle, velocity, time)

Check, if this polygon intersects with a (moving) circle. In case of a collision some additional information is calculated.

Parameters:
{Circle2} circle
{Vec2} velocity: Relative speed in units per second (assuming this polygon is static)
{float} time: seconds to look ahead (e.g. 1/30s for one frame step). Default: 1

Returns:: false, if no intersection, otherwise {...}

isCCW()

Check, if this polygon has a counterclocwise vertex order.

makeCCW()

Make sure this polygon has a counterclocwise vertex order.

makeCW()

Make sure this polygon has a clocwise vertex order.

makeFirst(idx)

Reorder polygon to start with given index.

Parameters:
{int} idx

Returns:: this

nearestPt(pt, cullingVector)

Return polygon point nearest to pt.

Parameters:
{Point2} pt
{Vec2} cullingVector: (optional) If we pass a velocity vector here, CCW oriented polygons will only consider objects aproaching from the outside.

perimeter(closed)

Return the total length of all line segments.

Parameters:
{boolean} closed: Include implicit closing segment (default: true).

remove(idx)

Remove point at index.

Parameters:
{int} idx

Returns:: this

revert()

Revert vertex list (in-place) and return this instance.

<static> Polygon2.revert(pg)

Return a reverse copy of a polygon.

Parameters:
pg

segmentIntersects(pt1, pt2)

Check, if line segment pt1, pt2 is inside this polygon.

Parameters:
pt1
pt2

set(xyList)

Parameters:
xyList

setCount(n)

Set maximum number of points (truncating trailing points).

Parameters:
n

swap(idx, idx2)

Exchange points.

Parameters:
{int} idx
idx2

Returns:: this

toString(prec)

Return string representation '[(x1,y1), (x2,y2), ...]'.

Parameters:
prec

<static> Polygon2.transform(pg, m)

Return a transformed copy of a polygon.

Parameters:
pg
m

transform(m)

Apply transformation matrix (in-place) and return this instance.

Parameters:
m

Classes

Class Polygon2