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Orbit Demo: Proper reset, and gravity physics simulation

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Tangent Wantwight 2024-01-24 00:43:03 -05:00
parent 9a261f6f3c
commit 04cbe84c24
1 changed files with 33 additions and 6 deletions
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39
debug/tick.ts
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@ -43,6 +43,8 @@ export function OrbitDemo() {
cx.scale(1 / 2, 1 / 2);
cx.translate(512, 512);
const G = 8000;
const PHYSICS_TICKS = 30;
const masses: {
x: number;
y: number;
@ -51,22 +53,47 @@ export function OrbitDemo() {
r: number;
m: number;
c: string;
}[] = [
{ x: 0, y: 0, vx: 0, vy: 0, r: 10, m: 10000, c: "yellow" },
{ x: -200, y: 200, vx: 100, vy: 100, r: 4, m: 4, c: "red" },
{ x: -450, y: 0, vx: 0, vy: 100, r: 5, m: 5, c: "blue" },
];
}[] = [];
const tickSource = tick(16);
const tickSource = tick(PHYSICS_TICKS);
let cancel: Cancel;
const begin = () => {
// reset / init
cancel?.();
masses.length = 0;
masses.push(
{ x: 0, y: 0, vx: -1, vy: -2, r: 10, m: 1000, c: "yellow" },
{ x: -150, y: 150, vx: 130, vy: 130, r: 9, m: 10, c: "red" },
{ x: -450, y: 0, vx: 0, vy: 120, r: 4, m: 5, c: "#0f8" }
);
// subscribe to source, stash cancellation func
cancel = tickSource((tick) => {
switch (tick[0]) {
case "physics":
// apply velocities
masses.forEach((mass) => {
mass.x += mass.vx * (1 / PHYSICS_TICKS);
mass.y += mass.vy * (1 / PHYSICS_TICKS);
});
// apply accelerations
masses.forEach((mass) => {
masses.forEach((other) => {
if (mass != other) {
const dx = other.x - mass.x;
const dy = other.y - mass.y;
const rSquared = dx ** 2 + dy ** 2;
const f = (G * other.m) / rSquared;
const d = Math.sqrt(rSquared);
const fx = (f * dx) / d;
const fy = (f * dy) / d;
mass.vx += fx / PHYSICS_TICKS;
mass.vy += fy / PHYSICS_TICKS;
}
});
});
break;
case "render":
const [, dt] = tick;