import { Vector2 } from "three" ; interface ClipInfo { /**
     * `true` if this vertex was clipped.
     */ isClipped ? : boolean ; } export type ClippedVertex = Vector2 & ClipInfo ; remarks internal export abstract class ClippingEdge { param point param extent abstract inside ( point , extent ) ; remarks Specialization of  https *    | line-line intersection}.
     *
     *  param a param b param extent abstract computeIntersection ( a , b , extent ) ; param polygon param extent return clipPolygon ( polygon , extent ) { const inputList = polygon ; polygon = [ ] ; const pushPoint = ( point ) => { const lastAddedPoint = polygon [ polygon . length - 1 ] ; if ( ! lastAddedPoint ?. equals ( point ) || ( point . isClipped === true && ! lastAddedPoint ?. isClipped ) || ( ! point . isClipped && lastAddedPoint ?. isClipped === true ) ) { polygon . push ( point ) ; } } ; for ( let i = 0 ; i < inputList . length ; ++ i ) { const currentPoint = inputList [ i ] ; const prevPoint = inputList [ ( i + inputList . length - 1 ) % inputList . length ] ; if ( this . inside ( currentPoint , extent ) ) { if ( ! this . inside ( prevPoint , extent ) ) { const p = this . computeIntersection ( prevPoint , currentPoint , extent ) ; p . isClipped = true ; pushPoint ( p ) ; } pushPoint ( currentPoint ) ; } else if ( this . inside ( prevPoint , extent ) ) { const p = this . computeIntersection ( prevPoint , currentPoint , extent ) ; p . isClipped = true ; pushPoint ( p ) ; } } return polygon ; } } class TopClippingEdge extends ClippingEdge { @override  inside ( point ) { return point . y >= 0 ; } remarks @override
     *
      computeIntersection ( a , b ) { const { x : x1 , y : y1 } = a ; const { x : x2 , y : y2 } = b ; const v = new Vector2 ( ( x1 * y2 - y1 * x2 ) / - ( y1 - y2 ) , 0 ) . round ( ) ; return v ; } } class RightClippingEdge extends ClippingEdge { @override
     *
     * See: HARP-14633, this should potentially be changed to < as it was previously.
     * However further investigation is needed to confirm this.
      inside ( point , extent ) { return point . x <= extent ; } remarks @override
     *
      computeIntersection ( a , b , extent ) { const { x : x1 , y : y1 } = a ; const { x : x2 , y : y2 } = b ; const v = new Vector2 ( extent , ( x1 * y2 - y1 * x2 - ( y1 - y2 ) * - extent ) / ( x1 - x2 ) ) . round ( ) ; return v ; } } class BottomClipEdge extends ClippingEdge { @override  inside ( point , extent ) { return point . y <= extent ; } remarks @override
     *
      computeIntersection ( a , b , extent ) { const { x : x1 , y : y1 } = a ; const { x : x2 , y : y2 } = b ; const v = new Vector2 ( ( x1 * y2 - y1 * x2 - ( x1 - x2 ) * extent ) / - ( y1 - y2 ) , extent ) . round ( ) ; return v ; } } class LeftClippingEdge extends ClippingEdge { @override  inside ( point ) { return point . x >= 0 ; } remarks @override
     *
      computeIntersection ( a , b ) { const { x : x1 , y : y1 } = a ; const { x : x2 , y : y2 } = b ; const v = new Vector2 ( 0 , ( x1 * y2 - y1 * x2 ) / ( x1 - x2 ) ) . round ( ) ; return v ; } } const clipEdges = [ new TopClippingEdge ( ) , new RightClippingEdge ( ) , new BottomClipEdge ( ) , new LeftClippingEdge ( ) ] ; remarks param polygon param extent export function clipPolygon ( polygon , extent ) { if ( polygon . length === 0 ) { return polygon ; } if ( ! polygon [ 0 ] . equals ( polygon [ polygon . length - 1 ] ) ) { polygon = [ ... polygon , polygon [ 0 ] ] ; } for ( const clip of clipEdges ) { polygon = clip . clipPolygon ( polygon , extent ) ; } if ( polygon . length < 3 ) { return [ ] ; } return polygon ; }