HTML JS Canvas 游戏：Tile Collision Bug 使玩家 Teleport Up

Question

我是游戏开发的初学者，一直在努力在一组图块和一个玩家矩形之间完成碰撞。该游戏具有跳跃和重力。首先碰撞有效，但非常笨重。有时，当玩家最终到达瓷砖顶部并稍微靠近边缘时，它会立即传送到右侧或左侧（取决于哪个边缘/角落）并掉落。与瓷砖底部碰撞时也会发生这种情况；玩家会立即传送到一边并走得更远。据我了解，瓷砖碰撞检测器会混淆与一侧或另一侧的碰撞，因为当玩家撞到瓷砖的边缘时，检测器会读取它，就好像它与两者发生碰撞一样，并决定将玩家放置在其他位置基于最高坐标速度（又名 speedX 和 speedY）。我通过将 speedY = 0 设置为每次碰到瓷砖的顶部来解决这个问题，这解决了这个问题，但又出现了另一个问题。现在，如果玩家在瓷砖顶部，然后跌落并很快向后扫射，它不会与瓷砖的侧面发生碰撞，而是很快又回到顶部。

我只需要一些关于如何解决此问题的提示，因为我尝试的一切都会导致另一个问题。我听说这是开发基于 2D 瓷砖的游戏中的常见错误。

这是一个运行代码的 jsfiddle：https://jsfiddle.net/8121u356/

这是我的整个代码的显示：

function startGame() {
    gameArea.start();
    actor = new player(32, 32, "green", 32, 32);
}

var mapArray = [
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,1,1,1,1,1,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,1,0,0,0,0],
    [0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,1,1,1,0,0,0,1,1,0,0,0,0,0,0],
    [1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1]

];

var levelRows = 20;
var levelCols = 20;
 var gameArea = {
     canvas : document.getElementById('canvas'),

     start : function() {
         this.context = this.canvas.getContext("2d");
         document.body.insertBefore(this.canvas, document.body.childNodes[0]);
         requestAnimationFrame(updateGameArea);
         window.addEventListener('keydown', function (e) {
             gameArea.keys = (gameArea.keys || []);
             gameArea.keys[e.keyCode] = true;
         });

         window.addEventListener('keyup', function (e) {
             gameArea.keys = (gameArea.keys || []);
             gameArea.keys[e.keyCode] = false;
         })
     },

     clear : function(){
         this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
     },
     render : function() {
         context = this.canvas.getContext("2d");
         var tileSize = 32;
         for(i=0;i<levelRows;i++){
             for(j=0;j<levelCols;j++){
                 if(mapArray[i][j]==1){
                     context.fillStyle = "gray";
                     context.fillRect(j*tileSize,i*tileSize,tileSize,tileSize);
                 }
             }
         }
     }
 };

function TileCollisionManager(object) {
    let tileSize = 32;
    let baseCol = Math.floor(object.x / tileSize);
    let baseRow = Math.floor(object.y / tileSize);
    let colOverlap = object.x % tileSize;
    let rowOverlap = Math.floor(object.y % tileSize);

    if (object.speedX > 0) { 
        if ((mapArray[baseRow][baseCol + 1] && !mapArray[baseRow][baseCol]) ||
            (mapArray[baseRow + 1][baseCol + 1] && !mapArray[baseRow + 1][baseCol] && rowOverlap)) {
            object.x = baseCol * tileSize;
        }
    }

    if (object.speedX < 0) {
        if ((!mapArray[baseRow][baseCol + 1] && mapArray[baseRow][baseCol]) ||
            (!mapArray[baseRow + 1][baseCol + 1] && mapArray[baseRow + 1][baseCol] && rowOverlap)) {
            object.x = (baseCol + 1) * tileSize;
        }
    }

    if (object.speedY > 0) { 
        if ((mapArray[baseRow + 1][baseCol] && !mapArray[baseRow][baseCol]) || 
            (mapArray[baseRow + 1][baseCol + 1] && !mapArray[baseRow][baseCol + 1] && colOverlap)) {
            object.y = ((baseRow) * tileSize);
            object.jumping = false;
            object.speedY = 0;
        }
    }

    if (object.speedY < 0) { 
        if ((!mapArray[baseRow + 1][baseCol] && mapArray[baseRow][baseCol]) ||
            (!mapArray[baseRow + 1][baseCol + 1] && mapArray[baseRow][baseCol + 1] && colOverlap)) {
            object.y = (baseRow + 1) * tileSize;
            object.speedY = 5;
        }
    }
 }
  function updateGameArea() {
      gameArea.clear();
      gameArea.render();
      actor.update();
      actor.newPos();
      actor.speedX = 0;
      actor.speedY += actor.gravity;


      if (gameArea.keys && gameArea.keys[39]) {
          actor.speedX = 4;
      }
      if (gameArea.keys && gameArea.keys[37]) {
          actor.speedX = -4;
      }
      if (gameArea.keys && gameArea.keys[32]) { 
          if (!actor.jumping) {
              actor.jumping = true;
              actor.speedY = -actor.speed * 3;
          }
      }


      TileCollisionManager(actor);
      requestAnimationFrame(updateGameArea);
  }


  function player (width, height, color, x, y) { 
      this.width = width;
      this.height = height;
      this.x = x;
      this.y = y;
      this.speedX=0;
      this.speedY=0;
      this.gravity=0.3;
      this.speed=3;
      this.jumping=false;
      this.color = color;
      this.update = function () {
          ctx = gameArea.context;
          ctx.fillStyle = this.color;
          ctx.fillRect(
              this.x,
              this.y,
              this.width, this.height);
      };
      this.newPos = function () {
          this.x += this.speedX;
          this.y += this.speedY;
      };

Answer 1

为您快速解决问题。

我已经看到你第三次发布这个问题了。您没有得到答案，因为最好的解决方案是大量的代码、复杂的，并且需要对您的代码进行大量更改。

所以我所做的是创建一个非常快速和简单的解决方案。

以正确的顺序解决冲突。

我没有在移动结束时检查位置，而是更改了代码以检查每个移动的像素。这是必需的，因为当玩家从一个位置移动到下一个位置时，您必须以正确的顺序找到碰撞。如果您在顶部或底部之前撞到一面墙，或者相反，它会产生影响，这就是导致您遇到问题的原因。你先检查 x 然后检查 y，这在很多情况下是错误的。

我还向actor添加了一个名为canMove的对象，它有4个属性，设置在每一帧的开头，用于防止玩家向被阻挡的方向移动。如果你让玩家朝一个被阻挡的方向移动，当你把钥匙朝那个方向按下时，它会卡在墙上。

我入侵了你的代码

对不起，我弄得有点乱，但时间不够。

为了帮助我编写我对其他一些模组所做的更改，我缩放了该游戏以适应窗口（缩放和调整大小都在 clear 函数中完成）。我更改了键盘界面以防止默认按下按键并设置箭头跳转以及空格（我讨厌使用空格来跳转：P）。还要更改地图以使用字符串，因为将更改输入为数组很痛苦。

我不确定你希望演员在头部被击中时有何反应。我让它以与向上移动相同的速度向下弹跳，但它确实使跳跃和滑入狭窄的通道变得更加困难。

所以我想我已经完成了大部分工作，所以你可以继续你的游戏。

如果您有任何问题，请在 cmets 中提问。

   // NOTE  var | 0 is the same as Math.floor(var)

var mapArray = [
        "#                  #",
        "#                  #",
        "#  ###             #",
        "#           #      #",
        "#       ##  #####  #",
        "#                  #",
        "#                  #",
        "#    ##            #",
        "#      ##          #",
        "#                  #",
        "#      #####       #",
        "#                  #",
        "#                  #",
        "#       #####      #",
        "#                  #",
        "#                  #",
        "#       #     ##   #",
        "#      ###         #",
        "#     ##### ##     #",
        "####################",
    ].map(row => row.split("").map(cell=>cell==="#" ? 1 : 0));


    var levelRows = 20;
    var levelCols = 20;
    var tileX = 32;
    var tileY = 32;
    var gameArea = {
     canvas : document.getElementById('canvas'),
     ctx : document.getElementById('canvas').getContext("2d"),
     keys : {  // set them here so that can block defaults
        "37" : false,
        "38" : false,     // also jump
        "39" : false,
        "32" : false,     // jump
     },

     start : function() {
         document.body.insertBefore(this.canvas, document.body.childNodes[0]);
         requestAnimationFrame(updateGameArea);
         function keyEvent(e) { 
             if(gameArea.keys["" + e.keyCode] !== undefined){
              gameArea.keys["" + e.keyCode] = e.type === "keydown" 
              e.preventDefault();
             }
         }
         addEventListener('keydown', keyEvent);
         addEventListener('keyup', keyEvent);
         focus();
        },

        clear(){
            var minSize = Math.min(innerWidth,innerHeight);
            if (this.ctx.canvas.width !== minSize|| this.ctx.canvas.height !== minSize) {
                this.ctx.canvas.width = minSize;
                this.ctx.canvas.height = minSize;
            }
                
            this.ctx.setTransform(1,0,0,1,0,0);
            this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);
            
            // the next line scales the canvas rendering to fit.
            this.ctx.setTransform(
                minSize / (levelCols * tileX),
                0,
                0,
                minSize/ (levelRows * tileY),
                0,0
            );
        },
        render() {
            var ctx = this.ctx;
            for(i=0;i<levelRows;i++){
                for(j=0;j<levelCols;j++){
                    if(mapArray[i][j]==1){
                        ctx.fillStyle = "gray";
                        ctx.fillRect(j*tileX,i*tileY,tileX,tileY);
                    }
                }
            }
        }
    };

    function updateGameArea() { 
        gameArea.clear();
        actor.canMove.check();
        actor.speedX = 0;
        if(actor.canMove.down){
            actor.speedY += actor.gravity;
        }

        if (gameArea.keys[39] && actor.canMove.right) {
            actor.speedX = 4;
        }
        if (gameArea.keys[37]  && actor.canMove.left) {
            actor.speedX = -4;
        }
        if (actor.canMove.up && (gameArea.keys[32] || gameArea.keys[38])) { //jump
            if (!actor.jumping) {
                actor.jumping = true;
                actor.speedY = -actor.speed * 3;
            }
        }
        actor.move();  // collision is done here
        
        gameArea.render();
        actor.draw();

        requestAnimationFrame(updateGameArea);
    }

    function Player (width, height, color, x, y) { //player component
        this.width = width;
        this.height = height;
        this.x = x;
        this.y = y;
        this.speedX=0;
        this.speedY=0;
        this.gravity=0.3;
        this.speed=3;
        this.jumping=false;
        this.color = color;
        this.canMove = {
           left : true,
           right : true,
           up : true,
           down : true,
           actor : this,
           clear(){
              this.left = true;
              this.right = true;
              this.up = true;
              this.down = true;
           },
           check(){
              this.clear();
              var x = this.actor.x | 0;
              var y = this.actor.y | 0;
              var cx = x / tileX | 0;
              var cy = y / tileY | 0;
              if(x % tileX === 0){
                 if(getMap(cx-1,cy) === 1){                 
                   this.left = false;
                   if(y % tileY !== 0 && getMap(cx-1,cy +1) === 1){
                      this.left = false;
                   }
                 }
                 if(getMap(cx+1,cy) === 1){
                   this.right = false;
                   if(y % tileY !== 0 && getMap(cx+1,cy +1) === 1){
                      this.right = false;
                   }
                 }
              }
              if(y % tileY === 0){
                 if(getMap(cx,cy-1) === 1){                 
                   this.up = false;
                   if(x % tileX !== 0 && getMap(cx+1,cy -1) === 1){
                      this.up = false;
                   }
                 }
                 if(getMap(cx,cy+1) === 1){
                   this.down = false;
                   if(x % tileX !== 0 && getMap(cx+1,cy +1) === 1){
                      this.down = false;
                   }
                 }
              }
           }
        };

        this.draw = function () {
            var ctx = gameArea.ctx;
            ctx.fillStyle = this.color;
            ctx.fillRect(  this.x,this.y, this.width, this.height);
        };
        this.move = function() {
          var x = this.x;
          var y = this.y;
          var sx = this.speedX;
          var sy = this.speedY;
          var speed = Math.sqrt(sx * sx + sy * sy);
          if(speed > 0){
            sx /= speed;
            sy /= speed;
            for(var i = 0; i < speed; i++){
              var xx = (x + sx * i) | 0;
              var yy = (y + sy * i) | 0;
              var cx = xx / tileX | 0;
              var cy = yy / tileY | 0;
              if(sy > 0){
                if(getMap(cx,cy+1) === 1 || (xx % tileX !== 0 && getMap(cx + 1,cy+1))){
                  this.y = y = cy * tileY;
                  this.speedY = sy = speed < 4 ? 0 : -3;
                  this.jumping = false;
                }
              }else if(sy < 0){
                if(getMap(cx,cy) === 1 || (xx % tileX !== 0 && getMap(cx + 1,cy))){
                  cy += 1;
                  this.y = y = cy * tileY;
                  this.speedY = sy = -sy;  // changing -sy to 0 will stick momentarily to the roof.
                }
              }
              if(sx > 0){
                if(getMap(cx+1,cy) === 1 ||  (yy % tileY !== 0 && getMap(cx + 1,cy+1))){
                  this.x = x = cx * tileX;
                  this.speedX = sx = 0;
                }

              }else if(sx < 0){
                if(getMap(cx,cy) === 1 || (yy % tileY !== 0 && getMap(cx,cy+1))){
                  cx += 1;
                  this.x = x = cx * tileX;
                  this.speedX = sx = 0;
                }          
              }
            }
          }
          this.x += this.speedX;
          this.y += this.speedY;
        }
    }

    function getMap(x,y){
      if(y < 0 || y >= levelRows || x < 0 || x >= levelCols){
         return 1;
      }
      return mapArray[y][x];
    }
 

    gameArea.start();
    actor = new Player(32, 32, "green", 32, 32);

canvas { 
   position : absolute;
   top : 0px;
   left : 0px;
}

<canvas id = "canvas" width="640" height="640"></canvas>