aabb-tree/2dShapes/Polygon.js

Basic implementation of the AABB-Tree (Axis Aligned Box Bounding Tree)

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const AABB_1 = __importDefault(require("../AABB"));
class Polygon {
    constructor(shape) {
        this.shape = shape;
        if (shape.length < 2) {
            throw new Error('A polygon needs to have more than 2 sides');
        }
        let minX = Infinity;
        let maxX = -Infinity;
        let minY = Infinity;
        let maxY = -Infinity;
        shape.forEach(point => {
            if (point.X < minX) {
                minX = point.X;
            }
            if (point.X > maxX) {
                maxX = point.X;
            }
            if (point.Y < minY) {
                minY = point.Y;
            }
            if (point.Y > maxY) {
                maxY = point.Y;
            }
        });
        this.AABB = new AABB_1.default(minX, minY, null, maxX, maxY, null);
    }
    GetAABB() {
        return this.AABB;
    }
    ContainsPoint(point) {
        let hitCount = 0;
        for (let i = 0; i < this.shape.length; i++) {
            const point1 = this.shape[i];
            const point2 = this.shape[(i + 1) % this.shape.length];
            if (this.checkForHit(point1, point2, point)) {
                hitCount++;
            }
        }
        return hitCount > 0 && hitCount % 2 === 1;
    }
    checkForHit(point1, point2, rayStart) {
        if (point1.Y <= point2.Y) {
            if (rayStart.Y <= point1.Y || rayStart.Y > point2.Y || (rayStart.X >= point1.X && rayStart.X >= point2.X)) {
                return false;
            }
            else if (rayStart.X < point1.X && rayStart.X < point2.X) {
                return true;
            }
            else {
                return (rayStart.Y - point1.Y) / (rayStart.X - point1.X) > (point2.Y - point1.Y) / (point2.X - point1.X);
            }
        }
        else {
            return this.checkForHit(point2, point1, rayStart);
        }
    }
}
exports.default = Polygon;