remove color and stable universes

src/Body.ts

@@ -3,23 +3,21 @@ import Vector from './Vector'
 export default class Body {
  mass: number
  radius: number
- tailLength: number
- color: string
  position: Vector
  velocity: Vector
  acceleration: Vector = new Vector(0, 0, 0)
  externalForces: Vector[] = []
  netExternalForce: Vector = new Vector(0, 0, 0)
+ pastPositionsLength: number
  pastPositions: Vector[] = []
  maxVelocity: number | undefined
 
- constructor({ mass, radius, position, velocity, color, tailLength, maxVelocity }: {
+ constructor({ mass, radius, position, velocity, pastPositionsLength, maxVelocity }: {
  mass?: number
  radius?: number
  position: Vector
  velocity: Vector
- color?: string
- tailLength?: number
+ pastPositionsLength?: number
  maxVelocity?: number
  }) {
  if (mass === 0) {
@@ -28,9 +26,8 @@ export default class Body {
 
  this.mass = mass ?? 1000000
  this.radius = radius ?? 0.04
- this.tailLength = tailLength ?? 200
- this.color = color ?? '#000'
  this.position = position
+ this.pastPositionsLength = pastPositionsLength ?? 200
  this.pastPositions.push(position)
  this.velocity = velocity
  this.maxVelocity = maxVelocity
@@ -58,7 +55,7 @@ export default class Body {
  }
  const deltaPosition = this.velocity.scaleBy(deltaTime)
  this.position = this.position.sum(deltaPosition)
- if (this.pastPositions.length >= this.tailLength) {
+ if (this.pastPositions.length >= this.pastPositionsLength) {
  this.pastPositions.pop()
  }
  this.pastPositions.unshift(this.position)