从零开始手把手教你使用javascript+canvas开发一个
2020-12-31 本文已影响0人
__豆约翰__
项目演示
项目演示地址：
项目源码：
代码结构
本节做完效果
新增bullet.js
//子弹类
function Bullet(cxt,img,type,enemy,level,x,y,radius){
this.cxt = cxt;
this.img = img;
this.x = x;
this.y = y;
this.radius = radius;
this.radiusAll = radius * 2;
//子弹类型
this.type = type;
this.enemy = enemy;
//子弹级别
this.level = level;
this.sp = 5;
//穿刺弹的移动速度
this.lineAngle = this.getLineAngle();
if(x > enemy.x+20)this.lineAngle.xsp *= -1;
if(y > enemy.y+20)this.lineAngle.ysp *= -1;
this.lineEnemy = {};
}
Bullet.prototype = {
//子弹在图像中的对应
bulletMap : [{x:0,y:0},{x:10,y:0},{x:20,y:0},{x:30,y:0},{x:40,y:0}],
//画子弹
draw : function(){
Canvas.drawImg(this.cxt,this.img,this.bulletMap[this.type].x,this.bulletMap[this.type].y,this.radiusAll,this.radiusAll,this.x,this.y,this.radiusAll,this.radiusAll);
},
//更新子弹信息
update : function(enemyList){
var bulletInfo = BulletType[this.type]["level_"+this.level],
enemy;
//判断是否是穿刺子弹
if(this.type == 3){
this.x += this.lineAngle.xsp;
this.y += this.lineAngle.ysp;
if(this.y >= 500 || this.y <= 0 || this.x >= 500 || this.x <= 0){
return this.over();
}
//遍历每个敌人
for(var i=0,l=enemyList.length;i<l;i++){
enemy = enemyList[i];
if(!enemy)continue;
//如果穿刺过,跳过
if(this.lineEnemy[enemy.num])continue;
//判断子弹击中敌人
if(T.circleInCircle(this,{x:enemy.x+20,y:enemy.y+20,radius:20})){
this.lineHurt(enemy);
//将穿刺过的敌人保存
this.lineEnemy[enemy.num] = true;
}
}
}
//非穿刺弹
else{
//敌人死了,子弹结束
if(!this.enemy.islive)return this.over();
//移动的速度
var sp = this.getLineAngle();
if(this.x > this.enemy.x+20)this.x -= sp.xsp;
else if(this.x < this.enemy.x +20)this.x += sp.xsp;
if(this.y > this.enemy.y+20)this.y -= sp.ysp;
else if(this.y < this.enemy.y + 20)this.y += sp.ysp;
if(this.y >= 500 || this.y <= 0 || this.x >= 500 || this.x <= 0){
return this.over();
}
//判断子弹击中敌人
if(T.circleInCircle(this,{x:this.enemy.x+20,y:this.enemy.y+20,radius:20})){
return this.over(this.enemy);
}
}
},
//获取子弹对于敌人的移动速度
getLineAngle : function(){
var ydif = Math.abs(this.y-this.enemy.y-15),
xdif = Math.abs(this.x-this.enemy.x-15),
xsp,ysp;
if(ydif >= xdif){
ysp = this.sp;
xsp = Math.floor(this.sp * (xdif / ydif));
}
else {
xsp = this.sp;
ysp = Math.floor(this.sp * (ydif / xdif));
}
return {xsp:xsp,ysp:ysp};
},
//子弹结束
over : function(enemy){
//判断子弹是因为击中敌人而结束
if(enemy){
var effer = {},bType = BulletType[this.type]["level_"+this.level];
//设置子弹的效果
if(bType.forzen){
effer = {effer:"frozen",num:bType.forzen};
}
else if(bType.steal){
effer = {effer:"steal",num:bType.steal};
}
else if(bType.kill){
effer = {effer:"kill",num:bType.kill};
}
else effer = {effer:"nomal"};
//较少鸡蛋的生命
enemy.reduceLife(bType.hurt,effer);
}
//移除子弹
Game.bulletList.remove(this);
//设置穿刺子弹的击中敌人列表为空
this.lineEnemy = null;
return false;
},
//穿刺子弹的伤害敌人
lineHurt : function(enemy){
enemy.reduceLife(BulletType[this.type]["level_"+this.level].hurt,{effer:"normal"});
}
}
//子弹类型
var BulletType = [
{
level_1:{
hurt:10,steal:0
},
level_2:{
hurt:12,steal:0
},
level_3:{
hurt:12,steal:1
}
},
{
level_1:{
hurt:5,forzen:3000
},
level_2:{
hurt:8,forzen:4000
},
level_3:{
hurt:10,forzen:4000
}
},
{
level_1:{
hurt:12
},
level_2:{
hurt:15
},
level_3:{
hurt:20
}
},
{
level_1:{
hurt:100
},
level_2:{
hurt:200
},
level_3:{
hurt:300
}
},
{
level_1:{
hurt:15,kill:5
},
level_2:{
hurt:20,kill:8
},
level_3:{
hurt:30,kill:10
}
}
]
//更新所有子弹信息
function updateBullet(){
var bullet;
for(var i=0,l=Game.bulletList.length;i<l;i++){
bullet = Game.bulletList[i];
if(!bullet)continue;
bullet.update(Game.enemyList);
}
}
//画出所有子弹
function drawBullet(){
var bullet;
for(var i=0,l=Game.bulletList.length;i<l;i++){
bullet = Game.bulletList[i];
if(!bullet)continue;
bullet.draw();
}
}
Enemy.js
tower.js新增update函数
//更新塔的信息
update : function(enemyList){
//判断冷却时间
if(this.cd > 0){
this.cd -= 1;
return false;
}
var towerInfo = TowerType[this.type]["level_"+this.level],
canShot = towerInfo.bullet,
enemy;
this.cd = towerInfo.cd;
//遍历敌人
for(var i=0,l=enemyList.length;i<l;i++){
enemy = enemyList[i];
if(!enemy)continue;
//判断敌人是否在塔的攻击范围内
if(T.rectInCircle(enemy,{x:this.x+25,y:this.y+25,radius:towerInfo.scope})){
//可发送的子弹数减少
canShot -= 1;
//新增一个子弹,加入到子弹列表中
Game.bulletList.push(new Bullet(Game.canvasList.main,Game.imgList.bullet_img,this.type,enemy,this.level,this.x+20,this.y+20,5,5));
//如果可用子弹没了,退出
if(canShot <= 0)break;
}
}
}
