116 lines
2.5 KiB
JavaScript
116 lines
2.5 KiB
JavaScript
import {RESOLUTION} from '@/constants.js'
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import {System} from '@/ecs/index.js';
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class SpatialHash {
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constructor({x, y}) {
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this.area = {x, y};
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this.chunkSize = {x: RESOLUTION.x / 2, y: RESOLUTION.y / 2};
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this.chunks = Array(Math.ceil(this.area.x / this.chunkSize.x))
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.fill(0)
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.map(() => (
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Array(Math.ceil(this.area.y / this.chunkSize.y))
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.fill(0)
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.map(() => [])
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));
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this.data = {};
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}
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clamp(x, y) {
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return [
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Math.max(0, Math.min(x, this.area.x - 1)),
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Math.max(0, Math.min(y, this.area.y - 1))
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];
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}
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chunkIndex(x, y) {
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const [cx, cy] = this.clamp(x, y);
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return [
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Math.floor(cx / this.chunkSize.x),
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Math.floor(cy / this.chunkSize.y),
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];
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}
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remove(datum) {
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if (datum in this.data) {
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for (const [cx, cy] of this.data[datum]) {
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const chunk = this.chunks[cx][cy];
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chunk.splice(chunk.indexOf(datum), 1);
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}
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}
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this.data[datum] = [];
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}
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update({x0, x1, y0, y1}, datum) {
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this.remove(datum);
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for (const [x, y] of [[x0, y0], [x0, y1], [x1, y0], [x1, y1]]) {
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const [cx, cy] = this.chunkIndex(x, y);
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this.data[datum].push([cx, cy]);
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this.chunks[cx][cy].push(datum);
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}
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}
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}
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export default class UpdateSpatialHash extends System {
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static get priority() {
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return {
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after: 'CalculateAabbs',
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};
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}
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deindex(entities) {
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super.deindex(entities);
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for (const id of entities) {
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this.hash.remove(id);
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}
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}
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reindex(entities) {
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for (const id of entities) {
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if (1 === id) {
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this.hash = new SpatialHash(this.ecs.get(1).AreaSize);
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}
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}
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super.reindex(entities);
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for (const id of entities) {
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this.updateHash(this.ecs.get(id));
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}
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}
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updateHash(entity) {
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if (!entity.VisibleAabb) {
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return;
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}
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this.hash.update(entity.VisibleAabb, entity.id);
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}
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tick() {
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for (const entity of this.ecs.changed(['VisibleAabb'])) {
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this.updateHash(entity);
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}
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}
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nearby(entity) {
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const [cx0, cy0] = this.hash.chunkIndex(
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entity.Position.x - RESOLUTION.x * 0.75,
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entity.Position.y - RESOLUTION.x * 0.75,
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);
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const [cx1, cy1] = this.hash.chunkIndex(
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entity.Position.x + RESOLUTION.x * 0.75,
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entity.Position.y + RESOLUTION.x * 0.75,
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);
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const nearby = new Set();
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for (let cy = cy0; cy <= cy1; ++cy) {
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for (let cx = cx0; cx <= cx1; ++cx) {
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this.hash.chunks[cx][cy].forEach((id) => {
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nearby.add(this.ecs.get(id));
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});
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}
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}
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return nearby;
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}
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}
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