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#跟着小白一起学鸿蒙# [番外]一起学做Tetris(下)

作者：王石

简介

接着《#跟着小白一起学鸿蒙# [番外]一起学做Tetris(上)》我们完善了页面，增加了左右按键和之前方块显示，方块消除。

开发

1. 按键增加

之前我们布局一直是只有个Canvas控件，现在我们需要设置高度后增加一个Row的布局，并增加两个Button控件，以下就是基础的Hap的page文件：index.ets

  build() {
    Column() {
      Column() {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .onClick((ev: ClickEvent) => {
            console.info("click!!")
            this.doClick()
          })
          .onTouch((ev) => {
            console.info("touch:"+ev.type.toString())
            console.info("touch x:"+ev.touches[0].screenX.toString())
            console.info("touch y:"+ev.touches[0].screenY.toString())
          })

          .onReady(() =>{
            this.context.imageSmoothingEnabled = false
            this.randomType()
            this.drawall()
          })
      }
      .height('92%')
      .width('100%')
      Row() {
        Button() {    //按钮控件
          Text('左')
            .fontSize(20)
            .fontWeight(FontWeight.Bold)
        }.type(ButtonType.Capsule)
        .width('20%')
        .height('6%')
        .backgroundColor('#0D9FFB')
        .onClick(() => {    //点击事件
          if (this.left > 0) {
            this.moveAction -= 1
          }
        })
        Button() {    //按钮控件
          Text('右')
            .fontSize(20)
            .fontWeight(FontWeight.Bold)
        }.type(ButtonType.Capsule)
        .width('20%')
        .height('6%')
        .backgroundColor('#0D9FFB')
        .onClick(() => {    //点击事件
          if (this.rightX < 240) {
            this.moveAction += 1
          }
        })
      }

    }
    .width('100%')
    .height('100%')
    .backgroundColor("#cccccc")
  }

2. 游戏完善的说明

之前我们的游戏只有布局，方块显示和变形，在完善后我们增加了积累方块的显示，消除，计分，游戏结束判断等。

2.1 积累方块显示

drawBlockmap() {
    let bs = this.blockSize
    this.context.fillStyle = 'rgb(250,0,0)'
    for (let i=0;i<23;i++) {
      for (let j=0;j<9;j++) {
        //是否有方块
        if (this.blockmap[i][j] == 1) {
          let y = i * this.blockSize
          let x = j * this.blockSize
          this.context.fillRect(x, y, bs, bs)
          this.context.rect(x, y, bs, bs)
          console.info("drawBlockmap:"+x.toString()+":"+y.toString())
        }
      }
      this.context.stroke()
      console.info("drawBlockmap:"+this.storeBlock.length.toString())
    }
  }

因为都是画布画的，为了重绘已经存在的方块，我们应用二维数组blockmap表示，值为1则有方块，数组索引则表示绘制坐标位置：

2.2 判断是否到底还是到顶

  checkBlockmap() {
    if (this.storeBlock.length == 0) {
      if (this.slotBottomY >= 660) {
        return 1
      }
    } else {
      let coords = this.curBlockShap
      let startx = this.slotStartX + this.moveAction * this.blockSize
      let starty = this.slotStartY + this.step * this.blockSize
      for (let i=0;i<4;i++) {
        let x = startx + coords[i][0]*this.blockSize
        let y = starty + coords[i][1]*this.blockSize + this.blockSize
        for (let k=0;k<22;k++) {
          for (let l=0;l<9;l++) {
            if (this.blockmap[k][l] == 1) {
              let blocky = k * this.blockSize
              let blockx = l * this.blockSize
              //判断是否到底
              if ((x == blockx && y == blocky) || y > 660) {
                //判断是否到顶
                if (y == 210) {
                  this.context.drawImage( this.gameoverImg,this.startX,this.startY,300,90)
                  //到顶回2
                  return 2
                }
                //到底回1
                return 1
              }
            }
          }
        }
      }
    }
    return 0
  }

先判断是否到底，到底的同时判断是否到顶，如果到顶了就是满了，如果只是到底则表明游戏可以继续 ；

2.3 到底积累方块

stackBlock() {
    let block = []
    let coords = this.curBlockShap
    let startx = this.slotStartX + this.moveAction * this.blockSize
    let starty = this.slotStartY + this.step * this.blockSize
    for (let i=0;i<4;i++) {
      let x = startx + coords[i][0]*this.blockSize
      let y = starty + coords[i][1]*this.blockSize
      console.info("stackBlock x:"+x.toString()+"y:"+y.toString())
      let indexX = x/this.blockSize
      let indexY = y/this.blockSize
      this.blockmap[indexY][indexX] = 1
      console.info("stackBlock:"+indexX+":"+indexY)
      block.push([x,y])
    }
    this.storeBlock.push(block)

    console.info("stackBlock:"+this.storeBlock.length.toString())
  }

如果到底了，就用坐标计算出 索引，然后在blockmap里标识为1，说明此处有方块，这样方便后面的绘制的显示；

2.4 清除方块

cleanBlockmap() {
    //检查是否一行满了
    let needMove = 0
    for (let i=22;i>=0;i--) {
      let linecnt = 0
      for (let j = 8;j >= 0; j--) {
        //是否有方块
        if (this.blockmap[i][j] == 1) {
          linecnt += 1
        }
      }
      if (linecnt == 9) {
        //此行都是方块，消除，计分
        for (let j = 8;j >= 0; j--) {
          this.blockmap[i][j] = 0
        }
        needMove += 1
        this.score += 1
      } else if (needMove > 0) {
        for (let j = 8;j >= 0; j--) {
          this.blockmap[i+needMove][j] = this.blockmap[i][j]
          this.blockmap[i][j] = 0
        }
      }
    }
  }

二维数组的好处就是方便每行计数清除，然后从底向上再逐层替换；

2.5 绘制每一步

drawStep() {
    this.context.clearRect(0,0,this.context.width,this.context.height)
    this.step += 1
    this.drawBox()
    this.drawBlockmap()
    this.cleanBlockmap()
    this.drawSideBlock()
    this.drawBoxBlock()
    this.drawScore()
    let stepType = this.checkBlockmap()
    if ( stepType == 1) {
      this.stackBlock()
      this.step = 0
      this.randomType()
    } else if (stepType == 2) {
      this.state= 2
      this.context.drawImage( this.gameoverImg,this.startX,this.startY,300,90)
    }
  }

绘制每一步其实就是重绘界面，包括如果游戏结束显示game over

3. 游戏逻辑

简单的小游戏主体游戏逻辑为：等待开始，开始，结束流程图如下：

graph LR
timer开始 --> 方块下落
timer开始 --> click[点击]
click[点击] --> 方块变形
方块下落 --> |落到底| 能消除 --> 计分 --> 堆积
方块下落 --> |落到底| 不能消除 --> 堆积
堆积 --> |堆积到顶| 满了 --> 游戏结束
堆积 --> |堆积到顶| 未满 --> 方块下落

doClick() {
    if (this.state == 0) {
      this.direction += 1
    } else if (this.state == 2) {
      this.state = 0
      this.score = 0
      this.storeBlock = []
      this.initMap()
    }
  }

游戏结束后需要重新初始化内部数据。

4. 完整逻辑

@Entry
@Component
struct Index {
  @State message: string = 'Hello World'
  private settings: RenderingContextSettings = new RenderingContextSettings(true);
  private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings);
  private gameoverImg:ImageBitmap = new ImageBitmap("common/images/gameover.png")
  private blockType: number = 0
  private blockSize: number = 30
  private blockShapBasic = [
    [[0,0],[0,1],[0,2],[0,3]],
    [[0,0],[0,1],[0,2],[1,2]],
    [[0,0],[0,1],[1,1],[0,2]],
    [[0,0],[0,1],[1,1],[1,2]],
    [[0,0],[0,1],[1,0],[1,1]],
  ]
  private blockShap = [
    [[0,0],[0,1],[0,2],[0,3]],
    [[0,0],[0,1],[0,2],[1,2]],
    [[0,0],[0,1],[1,1],[0,2]],
    [[0,0],[0,1],[1,1],[1,2]],
    [[0,0],[0,1],[1,0],[1,1]],
  ]
  private blockmap = [];
  private curBlockShap = []
  private storeBlock = []
  private sideStartX = 300;
  private sideStartY = 150;
  private startX = 20
  private startY = 300

  private slotStartX = 120;
  private slotStartY = 150;
  private slotBottomY = 150;
  private xleft = 0;
  private rightX = 0;

  private score = 0;
  private step = 0;
  private direction = 0;
  private moveAction = 0;
  private state = 0;

  aboutToDisappear() {
  }

  aboutToAppear() {
    this.initMap()
    this.sleep(1000)
  }

  initMap() {
    for (let i=0;i<23;i++) {
      let item = []
      for (let j=0;j<9;j++) {
        item.push(0)
      }
      this.blockmap.push(item)
    }
  }

  async sleep(ms: number) {
    return new Promise((r) => {
      setInterval(() => {
//        console.log(this.message)
        if (this.state == 0) {
          this.drawStep()
        }
      }, ms)
    })
  }

  doClick() {
    if (this.state == 0) {
      this.direction += 1
    } else if (this.state == 2) {
      this.state = 0
      this.score = 0
      this.storeBlock = []
      this.initMap()
    }
  }

  drawBox() {
    this.context.lineWidth = 4
    this.context.beginPath()
    this.context.lineCap = 'butt'
    this.context.moveTo(0, 100)
    this.context.lineTo(270, 100)
    this.context.moveTo(270, 100)
    this.context.lineTo(270, 690)
    this.context.moveTo(0, 690)
    this.context.lineTo(270, 690)
  }

  setDirection() {
    this.curBlockShap = this.blockShap[this.blockType]
    if (this.direction > 0) {
      for (let i=0;i<4;i++) {
        let x = this.curBlockShap[i][0]
        this.curBlockShap[i][0] = this.curBlockShap[i][1]
        this.curBlockShap[i][1] = x
      }
      this.direction = 0
    }
  }

  drawSideBlock() {
    this.context.fillStyle = 'rgb(250,0,0)'
    let bs = this.blockSize
    let coords = this.blockShapBasic[this.blockType]
    for (let i=0;i<4;i++) {
      let x = this.sideStartX + coords[i][0]*this.blockSize
      let y = this.sideStartY + coords[i][1]*this.blockSize
      this.context.fillRect(x, y, bs, bs)
      this.context.rect(x, y, bs, bs)
//      console.info("x,y"+x.toString()+":"+y.toString())
    }
    this.context.stroke()
  }

  drawBoxBlock() {
    let min = 690
    let max = 0
    this.setDirection()
    this.context.fillStyle = 'rgb(250,0,0)'
    let bs = this.blockSize
    let coords = this.curBlockShap
    let startx = this.slotStartX + this.moveAction * this.blockSize
    let starty = this.slotStartY + this.step * this.blockSize
    for (let i=0;i<4;i++) {
      let x = startx + coords[i][0]*this.blockSize
      let y = starty + coords[i][1]*this.blockSize
      min = min > x ? x:min
      max = max < x ? x:max
      this.context.fillRect(x, y, bs, bs)
      this.context.rect(x, y, bs, bs)
//      console.info("x,y"+x.toString()+":"+y.toString())
      this.slotBottomY = y
      this.xleft = min
      this.rightX = max
    }
    this.context.stroke()
//    console.info("min,max"+min.toString()+":"+max.toString())
  }

  stackBlock() {
    let block = []
    let coords = this.curBlockShap
    let startx = this.slotStartX + this.moveAction * this.blockSize
    let starty = this.slotStartY + this.step * this.blockSize
    for (let i=0;i<4;i++) {
      let x = startx + coords[i][0]*this.blockSize
      let y = starty + coords[i][1]*this.blockSize
      console.info("stackBlock x:"+x.toString()+"y:"+y.toString())
      let indexX = x/this.blockSize
      let indexY = y/this.blockSize
      this.blockmap[indexY][indexX] = 1
      console.info("stackBlock:"+indexX+":"+indexY)
      block.push([x,y])
    }
    this.storeBlock.push(block)

    console.info("stackBlock:"+this.storeBlock.length.toString())
  }

  checkBlockmap() {
    if (this.storeBlock.length == 0) {
      if (this.slotBottomY >= 660) {
        return 1
      }
    } else {
      let coords = this.curBlockShap
      let startx = this.slotStartX + this.moveAction * this.blockSize
      let starty = this.slotStartY + this.step * this.blockSize
      for (let i=0;i<4;i++) {
        let x = startx + coords[i][0]*this.blockSize
        let y = starty + coords[i][1]*this.blockSize + this.blockSize
        for (let k=0;k<22;k++) {
          for (let l=0;l<9;l++) {
            if (this.blockmap[k][l] == 1) {
              let blocky = k * this.blockSize
              let blockx = l * this.blockSize
              //判断是否到底
              if ((x == blockx && y == blocky) || y > 660) {
                //判断是否到顶
                if (y == 210) {
                  this.context.drawImage( this.gameoverImg,this.startX,this.startY,300,90)
                  //到顶回2
                  return 2
                }
                //到底回1
                return 1
              }
            }
          }
        }
      }
    }
    return 0
  }

  cleanBlockmap() {
    //检查是否一行满了
    let needMove = 0
    for (let i=22;i>=0;i--) {
      let linecnt = 0
      for (let j = 8;j >= 0; j--) {
        //是否有方块
        if (this.blockmap[i][j] == 1) {
          linecnt += 1
        }
      }
      if (linecnt == 9) {
        //此行都是方块，消除，计分
        for (let j = 8;j >= 0; j--) {
          this.blockmap[i][j] = 0
        }
        needMove += 1
        this.score += 1
      } else if (needMove > 0) {
        for (let j = 8;j >= 0; j--) {
          this.blockmap[i+needMove][j] = this.blockmap[i][j]
          this.blockmap[i][j] = 0
        }
      }
    }
  }

  drawBlockmap() {
    let bs = this.blockSize
    this.context.fillStyle = 'rgb(250,0,0)'
    for (let i=0;i<23;i++) {
      for (let j=0;j<9;j++) {
        //是否有方块
        if (this.blockmap[i][j] == 1) {
          let y = i * this.blockSize
          let x = j * this.blockSize
          this.context.fillRect(x, y, bs, bs)
          this.context.rect(x, y, bs, bs)
          console.info("drawBlockmap:"+x.toString()+":"+y.toString())
        }
      }
      this.context.stroke()
      console.info("drawBlockmap:"+this.storeBlock.length.toString())
    }
  }

  drawScore() {
    this.context.fillStyle = 'rgb(0,0,0)'
    this.context.font = '80px sans-serif'
    this.context.fillText("Score:"+this.score.toString(), 20, 140)
  }

  randomType() {
    this.blockType = Math.floor(Math.random()*5)
    console.info("blocktype:"+this.blockType.toString())
  }

  drawStep() {
    this.context.clearRect(0,0,this.context.width,this.context.height)
    this.step += 1
    this.drawBox()
    this.drawBlockmap()
    this.cleanBlockmap()
    this.drawSideBlock()
    this.drawBoxBlock()
    this.drawScore()
    let stepType = this.checkBlockmap()
    if ( stepType == 1) {
      this.stackBlock()
      this.step = 0
      this.randomType()
    } else if (stepType == 2) {
      this.state= 2
      this.context.drawImage( this.gameoverImg,this.startX,this.startY,300,90)
    }
  }

  drawall() {
    this.drawBox()
    this.drawSideBlock()
    this.drawBoxBlock()
    this.drawScore()
  }

  build() {
    Column() {
      Column() {
        Canvas(this.context)
          .width('100%')
          .height('100%')
          .onClick((ev: ClickEvent) => {
            console.info("click!!")
            this.doClick()
          })
          .onTouch((ev) => {
            console.info("touch:"+ev.type.toString())
            console.info("touch x:"+ev.touches[0].screenX.toString())
            console.info("touch y:"+ev.touches[0].screenY.toString())
          })

          .onReady(() =>{
            this.context.imageSmoothingEnabled = false
            this.randomType()
            this.drawall()
          })
      }
      .height('92%')
      .width('100%')
      Row() {
        Button() {    //按钮控件
          Text('左')
            .fontSize(20)
            .fontWeight(FontWeight.Bold)
        }.type(ButtonType.Capsule)
        .width('20%')
        .height('6%')
        .backgroundColor('#0D9FFB')
        .onClick(() => {    //点击事件
          if (this.xleft > 0) {
            this.moveAction -= 1
          }
        })
        Button() {    //按钮控件
          Text('右')
            .fontSize(20)
            .fontWeight(FontWeight.Bold)
        }.type(ButtonType.Capsule)
        .width('20%')
        .height('6%')
        .backgroundColor('#0D9FFB')
        .onClick(() => {    //点击事件
          if (this.rightX < 240) {
            this.moveAction += 1
          }
        })
      }

    }
    .width('100%')
    .height('100%')
    .backgroundColor("#cccccc")
  }
}

遗留问题：

1. 有bug，方块变形不完整；

2. 可实现网络对战（分布式对战）；

5. 获取源码

等游戏完整发布，会有两个版本，单机和联机版本

总结

本文主要介绍了小游戏的开发，画布功能的使用，游戏逻辑，分布式