1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
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;
}
}
|
