Add start of ship rendering

js/world/body.mjs

@@ -0,0 +1,26 @@
+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.mass = mass;
+	}
+	
+	tickGravity(bodies) {
+		bodies.forEach(b => {
+			let force = b.mass / this.mass / (distanceTo(b) ** 2) * G;
+			let angle = Math.atan2(b.y - this.y, b.x - this.x);
+			this.xvel += Math.cos(angle) * force;
+			this.yvel += Math.sin(angle) * force;
+		});
+	}
+
+	distanceTo(body) {
+		return Math.sqrt(((body.x - this.x) ** 2) + ((body.y - this.y) ** 2));
+	}
+}