jumpstorm/client/lib/structures/QuadTree.ts
2023-07-19 20:38:24 -07:00

155 lines
3.9 KiB
TypeScript

import type { Coord2D, Dimension2D } from "../interfaces";
import { ComponentNames, BoundingBox } from "../components";
import { Entity } from "../entities";
interface BoxedEntry {
id: number;
dimension: Dimension2D;
center: Coord2D;
}
enum Quadrant {
I,
II,
III,
IV,
}
export class QuadTree {
private maxLevels: number;
private splitThreshold: number;
private level: number;
private topLeft: Coord2D;
private dimension: Dimension2D;
private children: Map<Quadrant, QuadTree>;
private objects: BoxedEntry[];
constructor(
topLeft: Coord2D,
dimension: Dimension2D,
maxLevels: number,
splitThreshold: number,
level?: number
) {
this.children = [];
this.objects = [];
this.maxLevels = maxLevels;
this.splitThreshold = splitThreshold;
this.level = level ?? 0;
}
public insert(id: number, dimension: Dimension2D, center: Coord2D): void {
if (this.hasChildren()) {
this.getIndices(boundingBox).forEach((i) =>
this.children[i].insert(id, dimension, center)
);
return;
}
this.objects.push({ id, dimension, center });
if (
this.objects.length > this.splitThreshold &&
this.level < this.maxLevels
) {
if (!this.hasChildren()) {
this.performSplit();
}
this.realignObjects();
}
}
public clear(): void {
this.objects = [];
if (this.hasChildren()) {
this.children.forEach((child) => child.clear());
this.children.clear();
}
}
public getNeighborIds(boxedEntry: BoxedEntry): number[] {
const neighbors: number[] = this.objects.map(({ id }) => id);
if (this.hasChildren()) {
this.getQuadrants(boxedEntry).forEach((quadrant) => {
this.children
.get(quadrant)
.getNeighborIds(boxedEntry)
.forEach((id) => neighbors.push(id));
});
}
return neighbors;
}
private performSplit(): void {
const halfWidth = this.dimension.width / 2;
const halfHeight = this.dimension.height / 2;
[
[Quadrant.I, { x: this.topLeft.x + halfWidth, y: this.topLeft.y }],
[Quadrant.II, { ...this.topLeft }],
[Quadrant.III, { x: this.topLeft.x, y: this.topLeft.y + halfHeight }],
[
Quadrant.IV,
{ x: this.topLeft.x + halfWidth, y: this.topLeft.y + halfHeight },
],
].forEach(([quadrant, pos]) => {
this.children.set(
quadrant,
new QuadTree(
pos,
{ width: halfWidth, height: halfHeight },
this.maxLevels,
this.splitThreshold,
this.level + 1
)
);
});
}
private getQuandrants(boxedEntry: BoxedEntry): Quadrant[] {
const treeCenter: Coord2D = {
x: this.topLeft.x + this.dimension.width / 2,
y: this.topLeft.y + this.dimension.height / 2,
};
return [
[Quadrant.I, (x, y) => x >= treeCenter.x && y < treeCenter.y],
[Quadrant.II, (x, y) => x < treeCenter.x && y < treeCenter.y],
[Quadrant.III, (x, y) => x < treeCenter.x && y >= treeCenter.y],
[Quadrant.IV, (x, y) => x >= treeCenter.x && y >= treeCenter.y],
]
.filter(
([_quadrant, condition]) =>
condition(
boxedEntry.center.x + boxedEntry.dimension.width / 2,
boxedEntry.center.y + boxedEntry.dimension.height / 2
) ||
condition(
boxedEntry.center.x - boxedEntry.dimension.width / 2,
boxedEntry.center.y - boxedEntry.dimension.height / 2
)
)
.map(([quadrant]) => quadrant);
}
private realignObjects(): void {
this.objects.forEach((boxedEntry) => {
this.getQuadrants(boxedEntry).forEach((direction) => {
this.children
.get(direction)
.insert(boxedEntry.id, boxedEntry.dimension, boxedEntry.center);
});
});
this.objects = [];
}
private hasChildren() {
return this.children && this.children.length > 0;
}
}