101 lines
2.6 KiB
JavaScript
101 lines
2.6 KiB
JavaScript
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import Animation from '../base/animation';
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import { SCREEN_WIDTH, SCREEN_HEIGHT } from '../render';
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const ENEMY_IMG_SRC = 'images/enemy.png';
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const ENEMY_WIDTH = 60;
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const ENEMY_HEIGHT = 60;
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const EXPLO_IMG_PREFIX = 'images/explosion';
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export default class Enemy extends Animation {
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speed = Math.random() * 2 + 1; // 飞行速度
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constructor() {
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super(ENEMY_IMG_SRC, ENEMY_WIDTH, ENEMY_HEIGHT);
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}
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init(speed) {
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this.x = 0;
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this.y = 0;
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// 随机选择一个边生成 (0:上, 1:右, 2:下, 3:左)
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const side = Math.floor(Math.random() * 4);
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switch (side) {
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case 0: // Top
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this.x = Math.random() * (SCREEN_WIDTH - this.width);
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this.y = -this.height;
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break;
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case 1: // Right
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this.x = SCREEN_WIDTH;
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this.y = Math.random() * (SCREEN_HEIGHT - this.height);
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break;
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case 2: // Bottom
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this.x = Math.random() * (SCREEN_WIDTH - this.width);
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this.y = SCREEN_HEIGHT;
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break;
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case 3: // Left
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this.x = -this.width;
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this.y = Math.random() * (SCREEN_HEIGHT - this.height);
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break;
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}
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// 计算朝向中心的速度向量
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const targetX = SCREEN_WIDTH / 2 - this.width / 2;
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const targetY = SCREEN_HEIGHT / 2 - this.height / 2;
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const dx = targetX - this.x;
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const dy = targetY - this.y;
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const distance = Math.sqrt(dx * dx + dy * dy);
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this.speed = speed || (Math.random() * 2 + 2); // 默认速度
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this.vx = (dx / distance) * this.speed;
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this.vy = (dy / distance) * this.speed;
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this.isActive = true;
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this.visible = true;
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// 设置爆炸动画
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this.initExplosionAnimation();
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}
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// 预定义爆炸的帧动画
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initExplosionAnimation() {
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const EXPLO_FRAME_COUNT = 19;
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const frames = Array.from(
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{ length: EXPLO_FRAME_COUNT },
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(_, i) => `${EXPLO_IMG_PREFIX}${i + 1}.png`
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);
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this.initFrames(frames);
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}
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// 每一帧更新敌人位置
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update() {
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if (GameGlobal.databus.isGameOver) {
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return;
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}
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this.x += this.vx;
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this.y += this.vy;
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// 如果到达中心（或者非常接近），可以视为撞击玩家（碰撞检测会处理）
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// 这里不需要额外的边界回收逻辑，因为它们最终会撞上玩家或被消灭
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}
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destroy() {
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this.isActive = false;
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// 播放销毁动画后移除
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this.playAnimation();
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GameGlobal.musicManager.playExplosion(); // 播放爆炸音效
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wx.vibrateShort({
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type: 'light'
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}); // 轻微震动
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this.on('stopAnimation', () => this.remove.bind(this));
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}
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remove() {
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this.isActive = false;
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this.visible = false;
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GameGlobal.databus.removeEnemy(this);
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}
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}
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