103 lines
2.1 KiB
JavaScript
103 lines
2.1 KiB
JavaScript
import {GRAVITATIONAL_CONSTANT as G} from '../consts.mjs';
|
|
|
|
export default class Body {
|
|
constructor(x, y, mass) {
|
|
this.x = x;
|
|
this.y = y;
|
|
this.r = 0;
|
|
this.xvel = 0;
|
|
this.yvel = 0;
|
|
this.rvel = 0;
|
|
this.rfriction = 0.9;
|
|
this.mass = mass;
|
|
}
|
|
|
|
get com() {
|
|
return [this.x, this.y];
|
|
}
|
|
|
|
get pos() {
|
|
return [this.x, this.y];
|
|
}
|
|
|
|
get speed() {
|
|
return Math.sqrt(this.xvel ** 2 + this.yvel ** 2);
|
|
}
|
|
|
|
getCelestialCollision(celestials) {
|
|
let result = false;
|
|
celestials.forEach(c => {
|
|
let dis = this.distanceTo(c);
|
|
if (dis < c.radius) result = c;
|
|
});
|
|
return result;
|
|
}
|
|
|
|
getWorldPoint(lx, ly) {
|
|
let [cx, cy] = this.localCom;
|
|
let [nx, ny] = this.rotateVector(lx - cx, ly - cy, this.r);
|
|
return [nx + this.x + cx, ny + this.y + cy];
|
|
}
|
|
|
|
getLocalPoint(wx, wy) {
|
|
let [lx, ly] = [wx - this.x, wy - this.y];
|
|
let [cx, cy] = this.localCom;
|
|
let [nx, ny] = this.rotateVector(lx, ly, -this.r);
|
|
return [nx - cx, ny - cy];
|
|
}
|
|
|
|
rotateVector(x, y, r = this.r) {
|
|
return [(x * Math.cos(r) - y * Math.sin(r)),
|
|
(y * Math.cos(r) - x * Math.sin(r))];
|
|
}
|
|
|
|
relativeVector(x, y) {
|
|
return this.rotateVector(x, y, this.r);
|
|
}
|
|
|
|
tickMotion() {
|
|
this.x += this.xvel;
|
|
this.y += this.yvel;
|
|
this.r += this.rvel;
|
|
this.rvel *= this.rfriction;
|
|
}
|
|
|
|
tickGravity(bodies) {
|
|
bodies.forEach(b => {
|
|
let force = b.mass / (this.distanceTo(b) ** 2) * G;
|
|
let [[ax, ay], [bx, by]] = [this.com, b.com];
|
|
let angle = Math.atan2(by - ay, bx - ax);
|
|
this.xvel += Math.cos(angle) * force;
|
|
this.yvel += Math.sin(angle) * force;
|
|
});
|
|
}
|
|
|
|
distanceTo(body) {
|
|
let [[ax, ay], [bx, by]] = [this.com, body.com];
|
|
return Math.max(Math.sqrt(((bx - ax) ** 2) +
|
|
((by - ay) ** 2)), 1);
|
|
}
|
|
|
|
angleTo(ax, ay, bx, by) {
|
|
return Math.atan2(by - ay, bx - ax);
|
|
}
|
|
|
|
approach(body, distance) {
|
|
let [[ax, ay], [bx, by]] = [this.com, body.com];
|
|
let angle = Math.atan2(by - ay, bx - ax);
|
|
this.x += Math.cos(angle) * distance;
|
|
this.y += Math.sin(angle) * distance;
|
|
}
|
|
|
|
halt() {
|
|
this.xvel = 0;
|
|
this.yvel = 0;
|
|
}
|
|
|
|
applyDirectionalForce(x, y, r) {
|
|
let [vx, vy] = this.rotateVector(x, y);
|
|
this.xvel += vx;
|
|
this.yvel += vy;
|
|
this.rvel += r / this.mass;
|
|
}
|
|
}
|