Android Canvas打飞机之别人家的战斗机

2023年12月24日 169次阅读来源: Galaxy北爱

前面讲解了<a href=”http://www.jianshu.com/p/8b65e7e73f70″>主角</a>的诞生以及<a href=”http://www.jianshu.com/p/966a3e9d8bdf”>武器配置</a>，只有主角在主场岂不是太寂寞？所以今天这里主要来实现敌方战斗机的诞生。

1.敌机类型主要提供的样式不多，主要实现一下不同敌机出场的飞行轨迹。创建一个DrawEnemy的敌机类，并且定义敌机类型

public class DrawEnemy extends DrawGame {
    /**
     * 敌机类型
     */
    public final static int TYPE_A=1;
    public final static int TYPE_B=2;
    public final static int TYPE_C=3;
    public final static int TYPE_D=4;
    public final static int TYPE_E=5;
    public final static int TYPE_F=6;
    public final static int TYPE_G=7;
    public final static int TYPE_H=8;
    public final static int TYPE_I=9;
    public final static int TYPE_J=10;
    public final static int TYPE_K=11;
    public final static int TYPE_L=12;
    public final static int TYPE_M=13;
    public final static int TYPE_N=14;
    public final static int TYPE_O=15;
    public final static int TYPE_P=16;
    public final static int TYPE_Q=17;
    public final static int TYPE_R=18;
    public final static int TYPE_S=19;
    /**
     * 高级敌机
     */
    public final static int TYPE_T=20;
    /**
     * 高级敌机
     */
    public final static int TYPE_U=21;
    /**
     * 敌机自动跟踪主角
     */
    public final static int TYPE_V=22;
    /**
     * 敌机自动跟踪主角
     */
    public final static int TYPE_W=23;
    public final static int TYPE_X=24;
    public final static int TYPE_Y=25;
    public final static int TYPE_Z=26;

2.敌机主要特性有生命值，飞行轨迹，飞行速度，旋转运动，冲击模式，是否死亡等自定义的一些属性

/**
     * 敌机的生命值
     */
    private int mEnemyLife;
    /**
     * 当前敌机飞行模式
     */
    private int mEnemyType;
    /**
     * 敌机飞行速度
     */
    private float mEnemySpeed;
    private float mEnemySpeedX;
    private float mEnemySpeedY;
    /**
     * 敌机初始化位置距离左边上边的距离
     */
    private float mMarginLeft;
    private float mMarginTop;
    /**
     * 战机是否死亡
     */
    private boolean isDead;
    private Random mRandom;
    private float mAngle;
    /**
     * 敌机在某一位置停留
     * 位置从屏幕左上角计算
     */
    private boolean mEnemyStopLeft, mEnemyStopTop;
    /**
     * 让敌机在某一个位置停留一段时常
     */
    public int stopToTime;
    private float mTempEnemyY = 1f;

3.初始化敌机样式，类型包括追踪主角类型以及普通类型，追踪主角类型需要接收到主角在屏幕的位置，然后计算出敌机的追踪速度。

@Override
    void initialize(Object... objects) {
        super.initialize(objects);
        mRandom = new Random();
        this.mEnemy = (Bitmap) objects[0];
        this.mEnemyX = (float) objects[1];
        this.mEnemyY = (float) objects[2];
        this.mEnemyLife = (int) objects[3];
        this.mEnemyType = (int) objects[4];
        mMatrix = new Matrix();
        if(objects.length==6){//敌机去追杀主角的战机类型
            mEnemySpeedY = ScreenUtils.getScreenHeight(getContext())/100;
            mEnemySpeedX = ((float)objects[5]-this.mEnemyY)/100;
        }else{//普通类型，不可追踪主角
            onSetSpeed();
        }
    }

4.为了体验出游戏中的真实感，敌机的头部朝向需要对着主角的位置，这样才有一种灵活对战的感觉，实时实现角度根据主角变化

/**
     * 敌机相对于主角方向旋转
     * 保证敌机头部朝向跟随主机位置移动
     */
    private Bitmap getMatrixBitmap(){
        if(mAngle==0){
            return mEnemy;
        }
        mMatrix.reset();
        //旋转角度
        mMatrix.setRotate(mAngle);
        return Bitmap.createBitmap(mEnemy,0, 0, mEnemy.getWidth(), mEnemy.getHeight(), mMatrix, true);
    }

5.前面提到了两种模式，其中追踪主角模式就是敌机直接向主角方向移动

/**
     * 面向主角方向 重新计算移动坐标
     * isTrack 是否需要去追杀主角
     */
    public void getAngleRotate(float playerX,float playerY,boolean isTrack){
        float cx = playerX-mEnemyX;
        float cy = playerY-mEnemyY;
        float k = Math.abs(cy/cx);//计算偏移量 斜率
        mAngle = (float) (90-Math.toDegrees(Math.atan(k)));//把弧度转换成角度
        if(cx>0){
            mAngle = -mAngle;
        }
        if(isTrack){//重新计算坐标 追杀主角
            mEnemySpeedX = cx/50;
            mEnemySpeedY = cy/50;
            if(cy<0){
                mEnemySpeedY=-mEnemySpeedY;
            }
            if((cx<0&&mEnemySpeedX>0)||(cx>0&&mEnemySpeedX<0)){
                mEnemySpeedX=-mEnemySpeedX;
            }
        }
    }

6.根据不同敌机的类型计算出不同的战机运行速度。

/**
     * 计算敌机飞行速度
     */
    private void onSetSpeed(){
        float screenH = ScreenUtils.getScreenHeight(getContext());
        float screenW = ScreenUtils.getScreenWidth(getContext());
        switch (mEnemyType){
            case TYPE_E:
                float min = screenH/200;
                mEnemySpeed = new Random().nextInt(3)+min;
                break;
            case TYPE_R:
                mEnemySpeed  = screenH/160;
                mEnemySpeedX = 1;
                mEnemySpeedY = mEnemySpeed;
                break;
            case TYPE_S:
                mEnemySpeed = screenH/160;
                mEnemySpeedX = 1;
                mEnemySpeedY = mEnemySpeed;
                break;
            case TYPE_T:
                mEnemySpeed = 6;
                mEnemySpeedX = 2;
                mMarginLeft = mEnemy.getWidth()*3;
                mMarginTop = mEnemy.getHeight()*3;
                break;
            case TYPE_U:
                mEnemySpeed = 6;
                mEnemySpeedX = 2;
                mMarginLeft = screenW - mEnemy.getWidth()*4;
                mMarginTop = mEnemy.getHeight()*3;
                break;
            case TYPE_X:
                mEnemySpeed = screenH/80;
                mEnemySpeedX = mRandom.nextInt(10);
                if(mRandom.nextBoolean()){
                    mEnemySpeedX = -mEnemySpeedX;
                }
                mEnemySpeedY = screenH/160;
                break;
            case TYPE_Y:
                mEnemySpeed = screenH/160;
                mEnemySpeedX =screenH/160;
                mEnemySpeedY =screenH/160;
                break;
            case TYPE_Z:
                mEnemySpeed = screenH/220;
                break;
            default:
                mEnemySpeed = screenH/160f;
                break;
        }
    }```
######7.通过updateGame的方法来进行战机移动，updateGame中实现了26种运行的轨迹算法，其实就是通过改变敌机XY坐标进行对应的移动动画。

/**
* 更新敌机运行轨迹
* 并且判断敌机是否离开屏幕
/
@Override
void updateGame(){
float screenH = ScreenUtils.getScreenHeight(getContext());
float screenW = ScreenUtils.getScreenWidth(getContext());
switch (mEnemyType){
case TYPE_A://左边垂直下降
if(!isDead){
if(mEnemySpeed<=3){
mEnemySpeed+=1;
}
mEnemyY+=mEnemySpeed;
if(mEnemyY>screenH){
isDead=true;
}
}
break;
case TYPE_B:
if(!isDead){//向右倾斜下降
mEnemyX+=mEnemySpeed/2;
mEnemyY+=mEnemySpeed;
}
break;
case TYPE_C:
if(!isDead){//向左倾斜下降
mEnemyX-=mEnemySpeed/2;
mEnemyY+=mEnemySpeed;
}
break;
case TYPE_D:
if(!isDead){//右边垂直倾斜下降
if(mEnemySpeed<=3){
mEnemySpeed+=1;
}
mEnemyY+=mEnemySpeed;
}
break;
case TYPE_E:
if(!isDead){//普通模式子弹自动追踪主角
if(mEnemyY>screenH){
isDead = true;
break;
}
mEnemyY+=mEnemySpeed;
}
break;
case TYPE_F:
if(!isDead){//向右横向移动循环碰撞
if(mAngle>=360){
mAngle=0;
}
mAngle+=1;
if(mEnemyX>=screenW-mEnemy.getWidth()){
mEnemyStopLeft = true;
}else if(mEnemyX<=0){
mEnemyStopLeft = false;
}
if(mEnemyStopLeft){
mEnemyX-=mEnemySpeed;
}else{
mEnemyX+=mEnemySpeed;
}
mEnemyY+=mEnemySpeed/2;
}
break;
case TYPE_G:
if(!isDead){//向左横向移动循环碰撞
if(mAngle<=-360){
mAngle=0;
}
mAngle-=1;
if(mEnemyX<=0){
mEnemyStopLeft = true;
}else if(mEnemyX>screenW-mEnemy.getWidth()){
mEnemyStopLeft = false;
}
if(mEnemyStopLeft){
mEnemyX+=mEnemySpeed;
}else{
mEnemyX-=mEnemySpeed;
}
mEnemyY+=mEnemySpeed/2;
}
break;
case TYPE_H:
if(!isDead){//想右切面运行
if(mEnemyY>=screenH/2||mEnemyX>screenW-mEnemy.getWidth()){
mEnemyStopLeft = true;
}
if(mEnemyStopLeft){
if(mEnemyStopTop){
mEnemyX +=0;
mEnemyY +=mEnemySpeed;
}else{
mEnemyX-=mEnemySpeed/2;
mEnemyY-=mEnemySpeed/2;
}
if(mEnemyY<=0){
mEnemyStopTop = true;
}
}else{
mEnemyX+=mEnemySpeed/2;
mEnemyY+=mEnemySpeed/2;
}
}
break;
case TYPE_I:
if(!isDead){//想左切面运行
if(mEnemyY>=screenH/2||mEnemyX-mEnemy.getWidth()<=0){
mEnemyStopLeft = true;
}
if(mEnemyStopLeft){
if(mEnemyStopTop){
mEnemyX+=0;
mEnemyY+=mEnemySpeed;
}else{
mEnemyX+=mEnemySpeed/2;
mEnemyY-=mEnemySpeed/2;
}
if(mEnemyY<=0){
mEnemyStopTop = true;
}
}else{
mEnemyX-=mEnemySpeed/2;
mEnemyY+=mEnemySpeed/2;
}
}
break;
case TYPE_J:
if(!isDead){//右边V形运动
if(mEnemyY>=screenH/2){
mEnemyStopLeft = true;
}
if(mEnemyStopLeft){
mEnemyX+=mEnemySpeedX;
mEnemyY+=mEnemySpeedY;
}else{
mAngle=0;
mEnemyY+=mEnemySpeed;
mEnemyX+=mEnemySpeed/2;
}
}
break;
case TYPE_K:
if(!isDead){//左边V形运动
if(mEnemyY>=screenH/2){
mEnemyStopLeft = true;
}
if(mEnemyStopLeft){
mEnemyX+=mEnemySpeedX;
mEnemyY+=mEnemySpeedY;
}else{
mAngle=0;
mEnemyY+=mEnemySpeed;
mEnemyX-=mEnemySpeed/2;
}
}
break;
case TYPE_L:
if(!isDead){//向上冲锋战斗机
if(mEnemyStopLeft){
mEnemyY-=mEnemySpeed/2;
stopToTime++;
if(mEnemyY<0||mEnemyY>screenH){
isDead = true;
break;
}
if(mEnemyY<=screenH/7){
if(stopToTime >=500){
mEnemySpeed=20;
}else{
mEnemyStopLeft =false;
}
}
}else{
mEnemyY+=mEnemySpeed/2;
if(mEnemyY>=screenH/3){
mEnemyStopLeft = true;
}
}
}
break;
case TYPE_M:
if(!isDead){//向下冲锋战斗机
if(mEnemyStopLeft){
stopToTime++;
mEnemyY-=mEnemySpeed/2;
if(mEnemyY<=screenH/7){
mEnemyStopLeft =false;
}
}else{
if(stopToTime >=500){
mEnemySpeed=20;
}
mEnemyY+=mEnemySpeed/2;
if(mEnemyY>=screenH/4){
if(stopToTime <300){
mEnemyStopLeft = true;
}else if(mEnemyY<0||mEnemyY>screenH){
isDead = true;
break;
}
}
}
}
break;
case TYPE_N://左边由上至上到中间
if(mEnemyStopLeft){
mEnemyY-=mEnemySpeed;
mEnemyX+=mEnemySpeed/2;
if(mEnemyY<=mEnemy.getHeight()&&mEnemyX>=screenW/2-mEnemy.getWidth()){
mEnemyStopTop = true;
mEnemyStopLeft = false;
}
if(mEnemyY<mEnemy.getHeight()){
mEnemyY = mEnemy.getHeight();
}
if(mEnemyX>screenW/2-mEnemy.getWidth()){
mEnemyX = screenW/2-mEnemy.getWidth();
}
}else{
if(mEnemyStopTop){
mEnemyY+=mEnemySpeed;
if(mEnemyY>screenH){
isDead = true;
break;
}
}else{
mEnemyY+=mEnemySpeed3;
if(mEnemyY>=(screenH/2)){
mEnemyStopLeft = true;
}
}
}
break;
case TYPE_O://右边由上至上到中间
if(mEnemyStopLeft){
mEnemyY-=mEnemySpeed;
mEnemyX-=mEnemySpeed/2;
if(mEnemyY<=mEnemy.getHeight()&&mEnemyY<=screenW/2+mEnemy.getWidth()){
mEnemyStopTop = true;
mEnemyStopLeft = false;
}
if(mEnemyY<mEnemy.getHeight()){
mEnemyY = mEnemy.getHeight();
}
if(mEnemyX<screenW/2+mEnemy.getWidth()){
mEnemyX = screenW/2+mEnemy.getWidth();
}
}else{
if(mEnemyStopTop){
mEnemyY+=mEnemySpeed;
}else{
mEnemyY+=mEnemySpeed*3;
if(mEnemyY>=screenH/2){
mEnemyStopLeft = true;
}
}
}
break;
case TYPE_P://左侧Z字形运动
if(mEnemyX>=screenW-mEnemy.getWidth()){
mEnemyStopLeft = true;
}else if(mEnemyX<=0){
mEnemyStopLeft = false;
}
if(mEnemyY<=0){
mTempEnemyY = -mTempEnemyY;
}
if(mEnemyStopLeft){
mEnemyY-= mTempEnemyY *2;
mEnemyX-=mEnemySpeed;
}else{
mEnemyY-= mTempEnemyY *2;
mEnemyX+=mEnemySpeed;
}
break;
case TYPE_Q://右侧z字形运动
if(mEnemyX<=0){
mEnemyStopLeft = true;
}else if(mEnemyX>=screenW-mEnemy.getWidth()){
mEnemyStopLeft = false;
}
if(mEnemyY<=0){
mTempEnemyY = -mTempEnemyY;
}
if(mEnemyStopLeft){
mEnemyY-= mTempEnemyY 2;
mEnemyX+=mEnemySpeed;
}else{
mEnemyY-= mTempEnemyY 2;
mEnemyX-=mEnemySpeed;
}
break;
case TYPE_R://左边中间螺旋出场
if(mAngle>=360){
mAngle = 0;
}
mAngle+=20;
if(mEnemyY>screenH/2+100){
mEnemySpeedY = – (mRandom.nextInt(3)+2);
}else if(mEnemyY<screenH/2){
mEnemySpeedY =mRandom.nextInt(3)+5;
}
mEnemyX+=mEnemySpeedX;
mEnemyY+=mEnemySpeedY;
if(mEnemyX>screenW){
isDead=true;
}
break;
case TYPE_S://右边中间螺旋出场
if(mAngle<=-360){
mAngle = 0;
}
mAngle-=20;
if(mEnemyY>screenH/2+100){
mEnemySpeedY = – (new Random().nextInt(3)+2);
}else if(mEnemyY<screenH/2){
mEnemySpeedY = (new Random().nextInt(3)+5);
}
mEnemyX-=mEnemySpeedX;
mEnemyY+=mEnemySpeedY;
if(mEnemySpeedX<0){
isDead=true;
}
break;
case TYPE_T://左边高级将领
if(mEnemyStopLeft){
if(mEnemyX>=mMarginLeft||mEnemyX<=0){
mEnemySpeedX= -mEnemySpeedX;
}
mEnemyY+=mEnemySpeedX2;
if(mEnemyY>=mMarginTop){
mEnemyY = mMarginTop;
}
if(mEnemyY<=mEnemy.getHeight()){
mEnemyY=mEnemy.getHeight();
}
}else{
if(mEnemyX>=mMarginLeft){
mEnemySpeedX= -mEnemySpeedX;
mEnemyStopLeft =true;
}
}
mEnemyX+=mEnemySpeedX;
break;
case TYPE_U://右边高级将领
if(mEnemyStopLeft){
if(mEnemyX<=mMarginLeft||mEnemyX>screenW-mEnemy.getWidth()){
mEnemySpeedX= -mEnemySpeedX;
}
mEnemyX+=mEnemySpeedX2;
if(mEnemyY>=mMarginTop){
mEnemyY = mMarginTop;
}
if(mEnemyY<=mEnemy.getHeight()){
mEnemyY=mEnemy.getHeight();
}
}else{
if(mEnemyX<=mMarginLeft){
mEnemySpeedX= -mEnemySpeedX;
mEnemyStopLeft =true;
}
}
mEnemyX-=mEnemySpeedX;
break;
case TYPE_V://左边自动追踪
stopToTime++;
mEnemyY+=mEnemySpeedY;
mEnemyX+=mEnemySpeedX;
if(!mEnemyStopLeft){
if(mEnemyY>=screenH/4){
mEnemyStopLeft = true;
}
if(stopToTime %25==0){
mEnemyX = -mEnemySpeedX;
}
}else if(mEnemyY<0||mEnemyY>screenH||mEnemyX>screenW||mEnemyX<0){
isDead=true;
}
break;
case TYPE_W://右边自动追踪
stopToTime++;
mEnemyY+=mEnemySpeedY;
mEnemyX+=mEnemySpeedX;
if(!mEnemyStopLeft){
if(mEnemyY>=screenH/4){
mEnemyStopLeft = true;
}
if(stopToTime %25==0){
mEnemySpeedX = -mEnemySpeedX;
}
}else if(mEnemyY<0||mEnemyY>screenH||mEnemyX>screenW||mEnemyX<0){
isDead=true;
}
break;
case TYPE_X://中空旋转混战模式
if(mAngle>=360){
mAngle = 0;
}
mAngle++;
mEnemyX+=mEnemySpeedX;
mEnemyY+=mEnemySpeedY;
if((mEnemyY>=screenH/2&&mEnemySpeedY>=0)||(mEnemyY<=0&&mEnemySpeedY<=0)){
mEnemySpeedY=-mEnemySpeedY;
if(mEnemySpeedY>=0){
mEnemySpeedY =mRandom.nextInt((int) mEnemySpeed);
}
}
if((mEnemyX>=screenW-mEnemy.getWidth()&&mEnemySpeedX>=0)||(mEnemyX<=0&&mEnemySpeedX<=0)){
mEnemySpeedX = -mEnemySpeedX;
if(mEnemySpeedX>=0){
mEnemySpeedX = mRandom.nextInt((int) mEnemySpeed);
}
}
break;
case TYPE_Y://高级将领
if(mAngle<=-360){
mAngle=0;
}
mAngle-=2;
mEnemyX+=mEnemySpeedX;
mEnemyY+=mEnemySpeedY;
if((mEnemyY>=screenH-mEnemy.getHeight()&&mEnemySpeedY>=0)||(mEnemyY<=0&&mEnemySpeedY<=0)){
mEnemySpeedY=-mEnemySpeedY;
}
if((mEnemyX>=screenW-mEnemy.getWidth()&&mEnemySpeedX>=0)||(mEnemyX<=0&&mEnemySpeedX<=0)){
mEnemySpeedX = -mEnemySpeedX;
}
break;
case TYPE_Z:
mEnemyY+=mEnemySpeed;
break;
}
//消失在屏幕以后敌机失效死亡
if(mEnemyX>screenW||mEnemyY>screenH||mEnemyX<-1){
isDead=true;
}
}

敌机和前面讲过的子弹逻辑一样，一旦移动出屏幕或者不可见了，通过判断变量isDead移除画布。

为了保证游戏后面的逻辑性以及学习思路的正常进行，并且保证打飞机的效果，最后实现出来感觉就跟一个正常游戏基本一样，所以这里写算法消耗的时间有点多，但是通过敌机类可以更好的学习一些移动，旋转等动画，能够以后自定义实现高效率动画控件的时候提供非常大的帮助，敌机类暂时还没有在GameView中使用，考虑到后面学习过程的顺畅性以及不饶弯路，那么在下一节我会模拟实现一个游戏关卡，通过关卡来模拟敌机出场的顺序和游戏对战，包括后面的碰撞效果。

敌机类源码已经通过Git更新。

<a href="https://github.com/tangyxgit/GameCanvas">我是持续性更新的源码</a>

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    原文作者：Galaxy北爱
    原文地址: https://www.jianshu.com/p/1114eca3393b
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