threejs-minecraft-39

class PhysicsEngine {
  constructor( scene, camera ) {
    // ... other code snippet
    this.scene = scene;
    this.camera = camera;

    // ... other code snippet

    this.bullets = [];
    this.bulletMeshes = [];

    this.shotHandler = ( event ) => this.shot( event );
  }

  initialize() {
    // Find this lien, comment it out and then add the below line
    // sphereBody.position.set( 0, 5, 0 );
    sphereBody.position.set( 10, 0, 10 );

    // ... other code snippet

    this.bindEvents();
  }

  uninitialize() {
    this.clearEvents();
  }

  bindEvents() {
    window.addEventListener(
      'click',
      this.shotHandler
    );
  }

  clearEvents() {
    window.removeEventListener(
      'click',
      this.shotHandler
    );
  }

  mock( count ) {
    // Find this lien, comment it out and then add the below line
    // scene.add( boxMesh );
    thia.scene.add( boxMesh );
  }

  shot( event ) {
    if( !event ) return;

    if( this.bullets.length >= 10 ) {
      for( let i = 0; i < this.bullets.length; i++ ) {
        this.bulletMeshes[i].geometry.dispose();
        this.scene.remove( this.bulletMeshes[i] );
        this.world.remove( this.bullets[i] );
      }
      this.bullets.length = 0;
      this.bulletMeshes.length = 0;
    }

    const ballShape = new CANNON.Sphere( 0.2 );
    const ballGeometry = new THREE.SphereGeometry( ballShape.radius, 32, 32 );
    const shootVelocity = 15;
    const ballMass = 20;
    const ballColor = 0x93882f;

    // 取得目前玩家位置
    const playerBody = this. sphereBody;
    let x = playerBody.position.x;
    let y = playerBody.position.y;
    let z = playerBody.position.z;

    // 子彈剛體與網格
    const ammoBody = new CANNON.Body({ mass: ballMass })
    ammoBody.addShape( ballShape );
    const ammoMaterial = new THREE.MeshStandardMaterial({ color: ballColor });
    const ammoMesh = new THREE.Mesh( ballGeometry, ammoMaterial );
    this.world.addBody( ammoBody );
    this.scene.add( ammoMesh );
    ammoMesh.castShadow = true;
    ammoMesh.receiveShadow = true;
    this.bullets.push( ammoBody );
    this.bulletMeshes.push( ammoMesh );

    // 取得滑鼠在網頁上 (x, y) 位置
    const raycaster = new THREE.Raycaster();
    let shootDirection = new THREE.Vector3();
    let mouse = new THREE.Vector2();

    mouse.x = ( event.clientX / window.innerWidth ) * 2 - 1;
    mouse.y = -( event.clientY / window.innerHeight ) * 2 + 1;

    // 透過 raycaster 取得目前玩家朝向方向
    raycaster.setFromCamera( mouse, this.camera );
    // 取得 raycaster 方向並決定發射方向
    shootDirection.copy( raycaster.ray.direction );

    ammoBody.velocity.set(
      shootDirection.x * shootVelocity,
      shootDirection.y * shootVelocity,
      shootDirection.z * shootVelocity
    );

    // Move the ball outside the player sphere
    x += shootDirection.x * ( this.sphereShape.radius * 1.02 + ballShape.radius );
    y += shootDirection.y * ( this.sphereShape.radius * 1.02 + ballShape.radius );
    z += shootDirection.z * ( this.sphereShape.radius * 1.02 + ballShape.radius );
    ammoBody.position.set( x, y, z );
    ammoMesh.position.set( x, y, z );
  }

  update( navigation ) {
    // ... other code snippet

    // Update bullet mesh positions
    const bullets = this.bullets;
    const bulletMeshes = this.bulletMeshes;
    for( let i = 0; i < bullets.length; i++ ) {
      bulletMeshes[i].position.copy( bullets[i].position );
      bulletMeshes[i].quaternion.copy( bullets[i].quaternion );
    }
  }
}