Android 实现抖音小游戏潜艇大挑战的思路详解

<framelayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent">

 <!-- 相机 -->
 <textureview
 android:layout_width="match_parent"
 android:layout_height="match_parent"/>

 <!-- 后景 -->
 <com.my.ugame.bg.backgroundview
 android:layout_width="match_parent"
 android:layout_height="match_parent"/>
 
 <!-- 前景 -->
 <com.my.ugame.fg.foregroundview
 android:layout_width="match_parent"
 android:layout_height="match_parent"/>

</framelayout>

/**
 * 障碍物基类
 */
sealed class bar(context: context) {

 protected open val bmp = context.getdrawable(r.mipmap.bar)!!.tobitmap()

 protected abstract val srcrect: rect

 private lateinit var dstrect: rect

 private val paint = paint()

 var h = 0f
 set(value) {
  field = value
  dstrect = rect(0, 0, w.toint(), h.toint())
 }

 var w = 0f
 set(value) {
  field = value
  dstrect = rect(0, 0, w.toint(), h.toint())
 }

 var x = 0f
 set(value) {
  view.x = value
  field = value
 }

 val y
 get() = view.y

 internal val view by lazy {
 barview(context) {
  it?.apply {
  drawbitmap(
   bmp,
   srcrect,
   dstrect,
   paint
  )
  }
 }
 }

}

internal class barview(context: context?, private val block: (canvas?) -> unit) :
 view(context) {

 override fun ondraw(canvas: canvas?) {
 block((canvas))
 }
}

/**
 * 屏幕上方障碍物
 */
class upbar(context: context, container: viewgroup) : bar(context) {

 private val _srcrect by lazy(lazythreadsafetymode.none) {
 rect(0, (bmp.height * (1 - (h / container.height))).toint(), bmp.width, bmp.height)
 }
 override val srcrect: rect
 get() = _srcrect
}

/**
 * 屏幕下方障碍物
 */
class dnbar(context: context, container: viewgroup) : bar(context) {

 override val bmp = super.bmp.let {
 bitmap.createbitmap(
  it, 0, 0, it.width, it.height,
  matrix().apply { postrotate(-180f) }, true
 )
 }

 private val _srcrect by lazy(lazythreadsafetymode.none) {
 rect(0, 0, bmp.width, (bmp.height * (h / container.height)).toint())
 }

 override val srcrect: rect
 get() = _srcrect
}

/**
 * 后景容器类
 */
class backgroundview(context: context, attrs: attributeset?) : framelayout(context, attrs) {

 internal val barslist = mutablelistof<bars>()

 override fun onlayout(changed: boolean, left: int, top: int, right: int, bottom: int) {
 barslist.flatmap { listof(it.up, it.down) }.foreach {
  val w = it.view.measuredwidth
  val h = it.view.measuredheight
  when (it) {
  is upbar -> it.view.layout(0, 0, w, h)
  else -> it.view.layout(0, height - h, w, height)
  }
 }
 }

/**
 * 游戏结束，停止所有障碍物的移动
 */
 @uithread
 fun stop() {
 _timer.cancel()
 _anims.foreach { it.cancel() }
 _anims.clear()
 }

 /**
 * 定时刷新障碍物：
 * 1. 创建
 * 2. 添加到视图
 * 3. 移动
 */
 @uithread
 fun start() {
 _clearbars()
 timer().also { _timer = it }.schedule(object : timertask() {
  override fun run() {
  post {
   _createbars(context, barslist.lastornull()).let {
   _addbars(it)
   _movebars(it)
   }
  }
  }

 }, first_appear_delay_millis, bar_appear_interval_millis
 )
 }

 /**
 * 游戏重启时，清空障碍物
 */
 private fun _clearbars() {
 barslist.clear()
 removeallviews()
 }

 /**
 * 创建障碍物（上下两个为一组）
 */
 private fun _createbars(context: context, pre: bars?) = run {
 val up = upbar(context, this).apply {
  h = pre?.let {
  val step = when {
   it.up.h >= height - _gap - _step -> -_step
   it.up.h <= _step -> _step
   _random.nextboolean() -> _step
   else -> -_step
  }
  it.up.h + step
  } ?: _barheight
  w = _barwidth
 }

 val down = dnbar(context, this).apply {
  h = height - up.h - _gap
  w = _barwidth
 }

 bars(up, down)

 }

 /**
 * 添加到屏幕
 */
 private fun _addbars(bars: bars) {
 barslist.add(bars)
 bars.asarray().foreach {
  addview(
  it.view,
  viewgroup.layoutparams(
   it.w.toint(),
   it.h.toint()
  )
  )
 }
 }

 /**
 * 使用属性动画移动障碍物
 */
 private fun _movebars(bars: bars) {
 _anims.add(
  valueanimator.offloat(width.tofloat(), -_barwidth)
  .apply {
   addupdatelistener {
   bars.asarray().foreach { bar ->
    bar.x = it.animatedvalue as float
    if (bar.x + bar.w <= 0) {
    post { removeview(bar.view) }
    }
   }
   }

   duration = bar_move_duration_millis
   interpolator = linearinterpolator()
   start()
  })
 }

}

/**
 * 潜艇类
 */
class boat(context: context) {

 internal val view by lazy { boatview(context) }

 val h
 get() = view.height.tofloat()

 val w
 get() = view.width.tofloat()

 val x
 get() = view.x

 val y
 get() = view.y

 /**
 * 移动到指定坐标
 */
 fun moveto(x: int, y: int) {
 view.smoothmoveto(x, y)
 }

}

internal class boatview(context: context?) : appcompatimageview(context) {

 private val _scroller by lazy { overscroller(context) }

 private val _res = arrayof(
 r.mipmap.boat_000,
 r.mipmap.boat_002
 )

 private var _rotationanimator: objectanimator? = null

 private var _cnt = 0
 set(value) {
  field = if (value > 1) 0 else value
 }

 init {
 scaletype = scaletype.fit_center
 _startflashing()
 }

 private fun _startflashing() {
 postdelayed({
  setimageresource(_res[_cnt++])
  _startflashing()
 }, 500)
 }

 override fun computescroll() {
 super.computescroll()

 if (_scroller.computescrolloffset()) {

  x = _scroller.currx.tofloat()
  y = _scroller.curry.tofloat()

  // keep on drawing until the animation has finished.
  postinvalidateonanimation()
 }

 }

 /**
 * 移动更加顺换
 */
 internal fun smoothmoveto(x: int, y: int) {
 if (!_scroller.isfinished) _scroller.abortanimation()
 _rotationanimator?.let { if (it.isrunning) it.cancel() }

 val curx = this.x.toint()
 val cury = this.y.toint()

 val dx = (x - curx)
 val dy = (y - cury)
 _scroller.startscroll(curx, cury, dx, dy, 250)

 _rotationanimator = objectanimator.offloat(
  this,
  "rotation",
  rotation,
  math.todegrees(atan((dy / 100.todouble()))).tofloat()
 ).apply {
  duration = 100
  start()
 }

 postinvalidateonanimation()
 }
}

/**
 * 前景容器类
 */
class foregroundview(context: context, attrs: attributeset?) : framelayout(context, attrs),
 camerahelper.facedetectlistener {

 private var _isstop: boolean = false

 internal var boat: boat? = null

 /**
 * 游戏停止，潜艇不再移动
 */
 @mainthread
 fun stop() {
 _isstop = true
 }
 
 /**
 * 接受人脸识别的回调，移动位置
 */
 override fun onfacedetect(faces: array<face>, facesrect: arraylist<rectf>) {
 if (_isstop) return
 if (facesrect.isnotempty()) {
  boat?.run {
  val face = facesrect.first()
  val x = (face.left - _widthoffset).toint()
  val y = (face.top + _heightoffset).toint()
  moveto(x, y)
  }
  _face = facesrect.first()
 }
 }

}

 /**
 * 游戏开始时通过动画进入
 */
 @mainthread
 fun start() {
 _isstop = false
 if (boat == null) {
  boat = boat(context).also {
  post {
   addview(it.view, _width, _width)
   animatorset().apply {
   play(
    objectanimator.offloat(
    it.view,
    "y",
    0f,
    this@foregroundview.height / 2f
    )
   ).with(
    objectanimator.offloat(it.view, "rotation", 0f, 360f)
   )
   doonend { _ -> it.view.rotation = 0f }
   duration = 1000
   }.start()
  }
  }
 }
 }

class camerahelper(val mactivity: activity, private val mtextureview: textureview) {

 private lateinit var mcameramanager: cameramanager
 private var mcameradevice: cameradevice? = null
 private var mcameracapturesession: cameracapturesession? = null

 private var canexchangecamera = false      //是否可以切换摄像头
 private var mfacedetectmatrix = matrix()      //人脸检测坐标转换矩阵
 private var mfacesrect = arraylist<rectf>()      //保存人脸坐标信息
 private var mfacedetectlistener: facedetectlistener? = null    //人脸检测回调
 private lateinit var mpreviewsize: size

 /**
 * 初始化
 */
 private fun initcamerainfo() {
 mcameramanager = mactivity.getsystemservice(context.camera_service) as cameramanager
 val cameraidlist = mcameramanager.cameraidlist
 if (cameraidlist.isempty()) {
  mactivity.toast("没有可用相机")
  return
 }

 //获取摄像头方向
 mcamerasensororientation =
  mcameracharacteristics.get(cameracharacteristics.sensor_orientation)!!
 //获取streamconfigurationmap，它是管理摄像头支持的所有输出格式和尺寸
 val configurationmap =
  mcameracharacteristics.get(cameracharacteristics.scaler_stream_configuration_map)!!

 val previewsize = configurationmap.getoutputsizes(surfacetexture::class.java) //预览尺寸

 // 当屏幕为垂直的时候需要把宽高值进行调换，保证宽大于高
 mpreviewsize = getbestsize(
  mtextureview.height,
  mtextureview.width,
  previewsize.tolist()
 )

 //根据preview的size设置textureview
 mtextureview.surfacetexture.setdefaultbuffersize(mpreviewsize.width, mpreviewsize.height)
 mtextureview.setaspectratio(mpreviewsize.height, mpreviewsize.width)
 }

private fun getbestsize(
 targetwidth: int,
 targetheight: int,
 sizelist: list<size>
 ): size {
 val bigenough = arraylist<size>() //比指定宽高大的size列表
 val notbigenough = arraylist<size>() //比指定宽高小的size列表

 for (size in sizelist) {

  //宽高比 == 目标值宽高比
  if (size.width == size.height * targetwidth / targetheight
  ) {
  if (size.width >= targetwidth && size.height >= targetheight)
   bigenough.add(size)
  else
   notbigenough.add(size)
  }
 }

 //选择bigenough中最小的值 或 notbigenough中最大的值
 return when {
  bigenough.size > 0 -> collections.min(bigenough, comparesizesbyarea())
  notbigenough.size > 0 -> collections.max(notbigenough, comparesizesbyarea())
  else -> sizelist[0]
 }
		
		initfacedetect()
 }

 /**
 * 创建预览会话
 */
 private fun createcapturesession(cameradevice: cameradevice) {

 // 为相机预览，创建一个cameracapturesession对象
 cameradevice.createcapturesession(
  arraylistof(surface),
  object : cameracapturesession.statecallback() {

  override fun onconfigured(session: cameracapturesession) {
   mcameracapturesession = session
   session.setrepeatingrequest(
   capturerequestbuilder.build(),
   mcapturecallback,
   mcamerahandler
   )
  }

  },
  mcamerahandler
 )
 }

 private val mcapturecallback = object : cameracapturesession.capturecallback() {
 override fun oncapturecompleted(
  session: cameracapturesession,
  request: capturerequest,
  result: totalcaptureresult
 ) {
  super.oncapturecompleted(session, request, result)
  if (mfacedetectmode != capturerequest.statistics_face_detect_mode_off)
  handlefaces(result)

 }
 }

 /**
 * 处理人脸信息
 */
 private fun handlefaces(result: totalcaptureresult) {
 val faces = result.get(captureresult.statistics_faces)!!
 mfacesrect.clear()

 for (face in faces) {
  val bounds = face.bounds

  val left = bounds.left
  val top = bounds.top
  val right = bounds.right
  val bottom = bounds.bottom

  val rawfacerect =
  rectf(left.tofloat(), top.tofloat(), right.tofloat(), bottom.tofloat())
  mfacedetectmatrix.maprect(rawfacerect)

  var resultfacerect = if (mcamerafacing == capturerequest.lens_facing_front) {
  rawfacerect
  } else {
  rectf(
   rawfacerect.left,
   rawfacerect.top - mpreviewsize.width,
   rawfacerect.right,
   rawfacerect.bottom - mpreviewsize.width
  )
  }

  mfacesrect.add(resultfacerect)

 }
 
 		mactivity.runonuithread {
  mfacedetectlistener?.onfacedetect(faces, mfacesrect)
 }
 }

mactivity.runonuithread {
 mfacedetectlistener?.onfacedetect(faces, mfacesrect)
 }

 /**
 * 初始化人脸检测相关信息
 */
 private fun initfacedetect() {

 val facedetectmodes =
  mcameracharacteristics.get(cameracharacteristics.statistics_info_available_face_detect_modes) //人脸检测的模式

 mfacedetectmode = when {
  facedetectmodes!!.contains(capturerequest.statistics_face_detect_mode_full) -> capturerequest.statistics_face_detect_mode_full
  facedetectmodes!!.contains(capturerequest.statistics_face_detect_mode_simple) -> capturerequest.statistics_face_detect_mode_full
  else -> capturerequest.statistics_face_detect_mode_off
 }

 if (mfacedetectmode == capturerequest.statistics_face_detect_mode_off) {
  mactivity.toast("相机硬件不支持人脸检测")
  return
 }

 val activearraysizerect =
  mcameracharacteristics.get(cameracharacteristics.sensor_info_active_array_size)!! //获取成像区域
 val scaledwidth = mpreviewsize.width / activearraysizerect.width().tofloat()
 val scaledheight = mpreviewsize.height / activearraysizerect.height().tofloat()

 val mirror = mcamerafacing == cameracharacteristics.lens_facing_front

 mfacedetectmatrix.setrotate(mcamerasensororientation.tofloat())
 mfacedetectmatrix.postscale(if (mirror) -scaledheight else scaledheight, scaledwidth)// 注意交换width和height的位置！
 mfacedetectmatrix.posttranslate(
  mpreviewsize.height.tofloat(),
  mpreviewsize.width.tofloat()
 )

 }

class gamecontroller(
 private val activity: appcompatactivity,
 private val textureview: autofittextureview,
 private val bg: backgroundview,
 private val fg: foregroundview
) {
 
 private var camera2helperface: camerahelper? = null
 /**
 * 相机初始化
 */
 private fun initcamera() {
 camerahelper ?: run {
  camerahelper = camerahelper(activity, textureview).apply {
  setfacedetectlistener(object : camerahelper.facedetectlistener {
   override fun onfacedetect(faces: array<face>, facesrect: arraylist<rectf>) {
   if (facesrect.isnotempty()) {
    fg.onfacedetect(faces, facesrect)
   }
   }
  })
  }
 }
 }

sealed class gamestate(open val score: long) {
 object start : gamestate(0)
 data class over(override val score: long) : gamestate(score)
 data class score(override val score: long) : gamestate(score)
}

/**
 * 游戏状态
 */
 private val _state = mutablelivedata<gamestate>()
 internal val gamestate: livedata<gamestate>
 get() = _state

 /**
 * 游戏停止
 */
 fun stop() {
 bg.stop()
 fg.stop()
 _state.value = gamestate.over(_score)
 _score = 0l
 }

 /**
 * 游戏再开
 */
 fun start() {
 initcamera()
 fg.start()
 bg.start()
 _state.value = gamestate.start
 handler.postdelayed({
  startscoring()
 }, first_appear_delay_millis)
 }

 /**
 * 开始计分
 */
 private fun startscoring() {
 handler.postdelayed(
  {
  fg.boat?.run {
   bg.barslist.flatmap { listof(it.up, it.down) }
   .foreach { bar ->
    if (iscollision(
     bar.x, bar.y, bar.w, bar.h,
     this.x, this.y, this.w, this.h
    )
    ) {
    stop()
    return@postdelayed
    }
   }
  }
  _score++
  _state.value = gamestate.score(_score)
  startscoring()
  }, 100
 )
 }

/**
 * 碰撞检测
 */
 private fun iscollision(
 x1: float,
 y1: float,
 w1: float,
 h1: float,
 x2: float,
 y2: float,
 w2: float,
 h2: float
 ): boolean {
 if (x1 > x2 + w2 || x1 + w1 < x2 || y1 > y2 + h2 || y1 + h1 < y2) {
  return false
 }
 return true
 }

private fun startgame() {
 permissionutils.checkpermission(this, runnable {
  gamecontroller.start()
  gamecontroller.gamestate.observe(this, observer {
  when (it) {
   is gamestate.start ->
   score.text = "danger\nahead"
   is gamestate.score ->
   score.text = "${it.score / 10f} m"
   is gamestate.over ->
   alertdialog.builder(this)
    .setmessage("游戏结束！成功推进 ${it.score / 10f} 米! ")
    .setnegativebutton("结束游戏") { _: dialoginterface, _: int ->
    finish()
    }.setcancelable(false)
    .setpositivebutton("再来一把") { _: dialoginterface, _: int ->
    gamecontroller.start()
    }.show()
  }
  })
 })
 }