LinearEdge¶

Overview¶

A line segment (between two points).

@author Jonathan Olson <jonathan.olson@colorado.edu>

Class LinearEdge¶

import { LinearEdge } from 'scenerystack/alpenglow';

Constructor¶

new LinearEdge( startPoint : Vector2, endPoint : Vector2, containsFakeCorner )¶

Instance Methods¶

getLineIntegralArea() : number¶

If you take the sum of these for a closed polygon, it should be the area of the polygon.

getLineIntegralZero() : number¶

If you take the sum of these for a closed polygon, it should be zero (used to check computations).

serialize() : SerializedLinearEdge¶

toString() : string¶

Static Methods¶

fromPolygon( polygon : Vector2[] ) : LinearEdge[]¶

fromPolygons( polygons : Vector2[][] ) : LinearEdge[]¶

toPolygons( edges : LinearEdge[], epsilon ) : Vector2[][]¶

Returns a simplified version of the edges as a list of polygons.

NOTE: This is a low-performance method, mainly intended for debugging display.

withOppositesRemoved( edges : LinearEdge[], epsilon ) : LinearEdge[]¶

Detects edges that are exact opposites of other edges, and returns a new list of edges with those removed.

withOverlappingRemoved( edges : LinearEdge[], epsilon ) : LinearEdge[]¶

Detects ANY "opposite-direction" overlap between edges, and returns a new list of edges with those removed.

NOTE: This is a low-performance method, mainly intended for debugging display.

polygonsToShape( polygons : Vector2[][] ) : Shape¶

Returns a simplified version of the polygons as a kite Shape.

TODO: perhaps... move something like this to kite?

NOTE: This is a low-performance method, mainly intended for debugging display.

evaluateLineIntegralShoelaceArea( p0x : number, p0y : number, p1x : number, p1y : number ) : number¶

Cancelled subexpressions for fewer multiplications

evaluateLineIntegralArea( p0x : number, p0y : number, p1x : number, p1y : number ) : number¶

Without the subexpression cancelling

evaluateLineIntegralPartialCentroid( p0x : number, p0y : number, p1x : number, p1y : number ) : Vector2¶

If you take the sum of these for a closed polygon and DIVIDE IT by the area, it should be the centroid of the polygon.

evaluateLineIntegralZero( p0x : number, p0y : number, p1x : number, p1y : number ) : number¶

evaluateLineIntegralDistance( p0x : number, p0y : number, p1x : number, p1y : number ) : number¶

deserialize( obj : SerializedLinearEdge ) : LinearEdge¶

getPolygonArea( polygon : Vector2[] ) : number¶

getPolygonCentroid( polygon : Vector2[] ) : Vector2¶

getEdgesArea( clippedEdges : LinearEdge[] ) : number¶

evaluateClosestDistanceToOrigin( p0x : number, p0y : number, p1x : number, p1y : number ) : number¶

Given a line segment, returns the distance from the origin to the closest point on the line segment.

leftComparison( p0x : number, p0y : number, p1x : number, p1y : number, x : number, y : number ) : number¶

Tests if the point (x,y) is left/on/right of the infinite line determined by (p0x,p0y) and (p1x,p1y). Return: >0 for P2 left of the line through P0 and P1 =0 for P2 on the line <0 for P2 right of the line

windingContribution( p0x : number, p0y : number, p1x : number, p1y : number, x : number, y : number ) : number¶

Gets the winding contribution of an edge segment to a point with the Dan Sunday winding number algorithm.

See https://web.archive.org/web/20130126163405/http://geomalgorithms.com/a03-_inclusion.html

getWindingNumberEdges( edges : LinearEdge[], point : Vector2 ) : number¶

getWindingNumberPolygon( polygon : Vector2[], point : Vector2 ) : number¶

getWindingNumberPolygons( polygons : Vector2[][], point : Vector2 ) : number¶

addDistanceRange( startPoint : Vector2, endPoint : Vector2, point : Vector2, range : Range )¶

Given an edge defined by startPoint/endPoint, compute the range of distances from the given point to the edge, and add it to the range.

validateStartEndMatches( edges : LinearEdge[] )¶

Type SerializedLinearEdge¶

import type { SerializedLinearEdge } from 'scenerystack/alpenglow';

• startPoint:
• x: number
• y: number
• endPoint:
• x: number
• y: number
• containsFakeCorner: boolean

Source Code¶

See the source for LinearEdge.ts in the alpenglow repository.