src/entities/Projectile.js

import * as THREE from "three";

export class Projectile {
  constructor(pos, target, speed, scene, projectileEffect = null) {
    this.position = pos.clone();
    this.target = target;
    this.speed = speed;
    this.scene = scene;
    this.damage = 0; // Will be set by tower
    this.projectileEffect = projectileEffect;

    const geo = new THREE.SphereGeometry(0.15, 8, 8);
    const mat = new THREE.MeshStandardMaterial({
      color:
        projectileEffect && projectileEffect.color
          ? projectileEffect.color
          : 0xffe082,
      emissive:
        projectileEffect && projectileEffect.emissive
          ? projectileEffect.emissive
          : 0x553300,
    });
    const mesh = new THREE.Mesh(geo, mat);
    mesh.castShadow = true;
    mesh.position.copy(this.position);

    this.mesh = mesh;
    scene.add(mesh);
    this.alive = true;
  }

  update(dt, spawnHitEffect) {
    if (!this.alive) return "dead";
    if (!this.target || this.target.isDead()) {
      this.alive = false;
      return "dead";
    }

    const toTarget = new THREE.Vector3().subVectors(
      this.target.mesh.position,
      this.position
    );
    const dist = toTarget.length();

    if (dist < 0.4) {
      this.target.takeDamage(this.damage);
      // Apply on-hit effect if any
      if (
        this.projectileEffect &&
        this.projectileEffect.type === "slow" &&
        this.target.applySlow
      ) {
        const mult = this.projectileEffect.mult ?? 1.0;
        const duration = this.projectileEffect.duration ?? 0;
        this.target.applySlow(mult, duration);
      }
      spawnHitEffect(this.position);
      this.alive = false;
      return "hit";
    }

    toTarget.normalize();
    this.position.addScaledVector(toTarget, this.speed * dt);
    this.mesh.position.copy(this.position);

    return "ok";
  }

  destroy() {
    this.scene.remove(this.mesh);
  }
}