53 lines
1.6 KiB
JavaScript
53 lines
1.6 KiB
JavaScript
import {System} from '@/ecs/index.js';
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import {distance, normalizeVector} from '@/util/math.js';
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export default class Attract extends System {
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static queries() {
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return {
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default: ['Magnet'],
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};
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}
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tick(elapsed) {
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for (const entity of this.select('default')) {
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const {Magnet, Position} = entity;
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const aabb = {
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x0: Position.x - Magnet.strength / 2,
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x1: Position.x + (Magnet.strength / 2) - 1,
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y0: Position.y - Magnet.strength / 2,
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y1: Position.y + (Magnet.strength / 2) - 1,
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};
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let s = Magnet.strength;
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s = s * s;
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for (const other of this.ecs.system('Colliders').within(aabb)) {
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if (other === entity || !other.Magnetic) {
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continue;
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}
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const difference = {
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x: entity.Position.x - other.Position.x,
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y: entity.Position.y - other.Position.y,
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};
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const toward = normalizeVector(difference);
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let d = distance(entity.Position, other.Position);
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if (d > 0) {
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const inv = s * (1 / (d * d));
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let impulse = {
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x: toward.x * inv,
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y: toward.y * inv,
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};
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if (Math.sign(entity.Position.x - (impulse.x * elapsed + other.Position.x)) !== Math.sign(difference.x)) {
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impulse.x = difference.x / elapsed;
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}
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if (Math.sign(entity.Position.y - (impulse.y * elapsed + other.Position.y)) !== Math.sign(difference.y)) {
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impulse.y = difference.y / elapsed;
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}
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other.Forces.applyImpulse(impulse);
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}
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}
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}
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}
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}
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