agentscape/lib/numbers/Geometry.ts

Agentscape is a library for creating agent-based simulations. It provides a simple API for defining agents and their behavior, and for defining the environment in which the agents interact. Agentscape is designed to be flexible and extensible, allowing

import concaveman from 'concaveman'

export class Intersections {
    public static circleCircle(circle1: {x: number, y: number, r: number}, circle2: {x: number, y: number, r: number}) {
        const dx = circle1.x - circle2.x
        const dy = circle1.y - circle2.y
        const distance = Math.sqrt(dx * dx + dy * dy)
        return distance < (circle1.r + circle2.r)
    }
}

export default class Geometry {
    public static concaveHull (points: [number, number][], concavity?: number, lengthThreshold?: number): [number, number][] {
        if (points.length < 3) return points
    
        const hull = concaveman(points, concavity, lengthThreshold) as [number, number][]
    
        return hull
    }

    public static convexHull (points: [number, number][]): [number, number][] {
        if (points.length < 3) return points
      
        // Sort points by x, then by y
        const sorted = points.slice().sort((a, b) => (a[0] === b[0] ? a[1] - b[1] : a[0] - b[0]))
      
        const crossProduct = (o: [number, number], a: [number, number], b: [number, number]) => 
            (a[0] - o[0]) * (b[1] - o[1]) - (a[1] - o[1]) * (b[0] - o[0])
      
        const buildHull = (pts: [number, number][]) => {
            const hull: [number, number][] = []
            for (const p of pts) {
                while (hull.length >= 2 && crossProduct(hull[hull.length - 2], hull[hull.length - 1], p) <= 0) {
                    hull.pop()
                }
                hull.push(p)
            }
            return hull
        }
      
        const lowerHull = buildHull(sorted)
        const upperHull = buildHull(sorted.reverse())
      
        // Remove last point from each hull to avoid duplication
        lowerHull.pop()
        upperHull.pop()
      
        return lowerHull.concat(upperHull)
    }

    public static Intersections = Intersections
}