51 lines
1.1 KiB
JavaScript
51 lines
1.1 KiB
JavaScript
export default class SpatialHash {
|
|
|
|
constructor({x, y}) {
|
|
this.area = {x, y};
|
|
this.chunkSize = {x: 64, y: 64};
|
|
this.chunks = Array(Math.ceil(this.area.x / this.chunkSize.x))
|
|
.fill(0)
|
|
.map(() => (
|
|
Array(Math.ceil(this.area.y / this.chunkSize.y))
|
|
.fill(0)
|
|
.map(() => [])
|
|
));
|
|
this.data = {};
|
|
}
|
|
|
|
clamp(x, y) {
|
|
return [
|
|
Math.max(0, Math.min(x, this.area.x - 1)),
|
|
Math.max(0, Math.min(y, this.area.y - 1))
|
|
];
|
|
}
|
|
|
|
chunkIndex(x, y) {
|
|
const [cx, cy] = this.clamp(x, y);
|
|
return [
|
|
Math.floor(cx / this.chunkSize.x),
|
|
Math.floor(cy / this.chunkSize.y),
|
|
];
|
|
}
|
|
|
|
remove(datum) {
|
|
if (datum in this.data) {
|
|
for (const [cx, cy] of this.data[datum]) {
|
|
const chunk = this.chunks[cx][cy];
|
|
chunk.splice(chunk.indexOf(datum), 1);
|
|
}
|
|
}
|
|
this.data[datum] = [];
|
|
}
|
|
|
|
update({x0, x1, y0, y1}, datum) {
|
|
this.remove(datum);
|
|
for (const [x, y] of [[x0, y0], [x0, y1], [x1, y0], [x1, y1]]) {
|
|
const [cx, cy] = this.chunkIndex(x, y);
|
|
this.data[datum].push([cx, cy]);
|
|
this.chunks[cx][cy].push(datum);
|
|
}
|
|
}
|
|
|
|
}
|