followTarget

Permet à un objet de suivre un autre objet

How to use

triggers on self"spotted"

parameters

Parameter	Default Value	Type	Description
speed		number	280
stopDistance		number	0
retreat		boolean	false
tag		string	"player"
uTurnDelay		number	0.2
sight		number	200
loosingSight		number	400
jumpForce		number	800
jumping		boolean	true

example

followTarget({
  speed: 280,
  stopDistance: 0,
  retreat: false,
  tag: "player",
  uTurnDelay: 0.2,
  sight: 200,
  loosingSight: 400,
  jumpForce: 800,
  jumping: true
}),

Source

component.js

function followTarget(p) {
  const param = {
    speed: 280,
    stopDistance: 0,
    retreat: false,
    tag: "player",
    uTurnDelay: 0.2,
    sight: 200,
    loosingSight: 400,
    jumpForce: 800,
    jumping: true,
    ...p
  }
  return {
    direction: vec2(0, 0),
    facing: 1,
    target: null,
    retreatPos: null,
    id: "follow",
    add() {
      requestAnimationFrame(() => this.retreatPos = vec2(this.pos))
      this.on("respawn", () => this.target = null)
    },
    update() {
      const isOnSight = this.target != null && this.target.pos.dist(this.pos) < param.loosingSight
      const gravity = this.gravityScale != 0
      let t
      if (!isOnSight) this.target = this.getClosestTarget()
      if (this.target) {
        const d = this.pos.dist(this.target.pos)
        if (d > param.stopDistance) t = this.target.pos.sub(this.pos)
        else t = vec2(0, 0)
        if (gravity && param.jumping && t.y < -1 && this.isGrounded())
          this.jump(param.jumpForce)
      } else if (param.retreat) {
        const d = this.pos.dist(this.retreatPos)
        if (d > param.stopDistance) t = this.retreatPos.sub(this.pos)
        else t = vec2(0, 0)
      } else t = vec2(0, 0)
      if (gravity) t.y = 0
      tween(this.direction, t.unit(), param.uTurnDelay, (v) => (this.direction = v), easings.easeOutSin)
      this.move(this.direction.scale(param.speed))
      if (this.direction.len() > 0.1) this.facing = this.direction.unit().x
    },
    getClosestTarget() {
      const targets = get(param.tag, { recursive: true })
      let closestTarget, lastDistance
      for (const e of targets) {
        const d = this.pos.dist(e.pos)
        if ((lastDistance == null || lastDistance > d) && d < param.sight) {
          lastDistance = d
          closestTarget = e
          this.trigger("spotted")
        }
      }
      return closestTarget
    },
  }
}