子弹射击

Bullet.ts
private _lastCheckPos:Laya.Point = new Laya.Point(0, 0); // 上次检测的位置
/*** 检查两条线段是否相交 * 线段1: (x1, y1) -> (x2, y2)* 线段2: (x3, y3) -> (x4, y4)*/
isLinesIntersect(x1, y1, x2, y2, x3, y3, x4, y4) {let denom = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4);if (denom === 0) {return false; // 平行或共线
    }let t = ((x1 - x3) * (y3 - y4) - (y1 - y3) * (x3 - x4)) / denom;let u = -((x1 - x2) * (y1 - y3) - (y1 - y2) * (x1 - x3)) / denom;return t >= 0 && t <= 1 && u >= 0 && u <= 1;
}/*** 检查子弹是否与怪物矩形相撞* @param {Laya.Point} start 子弹起始位置* @param {Laya.Point} end 子弹结束位置* @param {Laya.Rectangle} rect 怪物矩形* @returns {boolean} 如果相撞返回 true，否则返回 false*/
checkBulletHit(start, end, rect) {// 1. 检查线段的两个端点是否在矩形内部if (rect.contains(start.x, start.y) || rect.contains(end.x, end.y)) {return true;}// 2. 检查线段是否与矩形的四条边相交// 定义矩形的四条边let left = rect.x;let right = rect.x + rect.width;let top = rect.y;let bottom = rect.y + rect.height;// 定义线段的两个端点let x1 = start.x;let y1 = start.y;let x2 = end.x;let y2 = end.y;// 检查线段是否与矩形的四条边相交// 左边if (this.isLinesIntersect(x1, y1, x2, y2, left, top, left, bottom)) return true;// 右边if (this.isLinesIntersect(x1, y1, x2, y2, right, top, right, bottom)) return true;// 上边if (this.isLinesIntersect(x1, y1, x2, y2, left, top, right, top)) return true;// 下边if (this.isLinesIntersect(x1, y1, x2, y2, left, bottom, right, bottom)) return true;// 如果都不相交return false;
}/*** 检查子弹是否与怪物最近的怪物相撞* @returns {boolean} 如果相撞返回 怪物，否则返回 null*/
checkHit(fishCtrl: FishCtrl): IFish {if (this._hasHit) return null;if (this._target) return null;let nowPos = new Laya.Point(this.x, this.y);let fishList = fishCtrl.getFishList();let minDistance = Number.MAX_VALUE;let targetMonster = null;for (let fishId in fishList) {let fish: IFish = fishList[fishId];let hitRect = fish.getHitRect();if (fish && fish.type != 0 && fish.canShoot && this.checkBulletHit(this._lastCheckPos, nowPos, hitRect)) {// 计算起点到怪物中心的距离let distance = this._lastCheckPos.distance(hitRect.x + hitRect.width / 2, hitRect.y + hitRect.height / 2);if (distance < minDistance) {minDistance = distance;targetMonster = fish;}}}this._lastCheckPos = nowPos;return targetMonster;}
private _dirction: Vector2;
step(time: number): number {let x = this.x + this._dirction.x * slet y = this.y + this._dirction.y * sthis.pos(x, y, true);
}init(uid: number, id: number, from: Vector2, to: Vector2): void {let a: number = to.x - from.x;let b: number = to.y - from.y;let m: number = Math.sqrt(a * a + b * b);this._dirction.x = a / m;this._dirction.y = b / m;this.pos(from.x, from.y, true);this._lastCheckPos = new Laya.Point(from.x, from.y);
}BulletCtrl.ts
Laya.timer.frameLoop(1, this, this.loop);private loop() {let now: number = getTime();for (let i = 0; i < this._bulletList.length; i++) {let fish: IFish, fishID: number;let b: Bullet = this._bulletList[i];if (b.hasHit) {b.hit();this._bulletList.splice(i, 1);i = i - 1;let count: number = this._bulletCnt[b.uid] || 0;this._bulletCnt[b.uid] = --count;} else {//移动fishID = b.step(now - this._lastTime);}// 检测是否击中let fish = b.checkHit(this._fishCtrl);if (fish) {fishID = fish.id;b.hit(); // 处理爆炸this._bulletList.splice(i, 1);i = i - 1;let count: number = this._bulletCnt[b.uid] || 0;this._bulletCnt[b.uid] = --count;}app.event(BulletCtrl.BULLET_HIT_FISH, { isrobot: b.isrobot, uid: b.uid, bullet_id: b.id, fishid: fishID, ls: [] });}this._lastTime = now;
}