Question

单击按下按钮，对象向一个方向移动。矩形必须只在一个方向旋转并重置到其原始位置。例如，它应该像在板球比赛中击球一样

///////代码//////

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<style>
canvas {
    border:1px solid #d3d3d3;
    background-color: #f1f1f1;
}
</style>
</head>
<body onload="startGame()">
<script>

var myGamePiece;

function startGame() {
    myGamePiece = new component(80, 15, "red", 225, 225);
    myGameArea.start();
}

var myGameArea = {
    canvas : document.createElement("canvas"),
    start : function() {
        this.canvas.width = 480;
        this.canvas.height = 270;
        this.context = this.canvas.getContext("2d");
        document.body.insertBefore(this.canvas, document.body.childNodes[0]);
        this.frameNo = 0;
        this.interval = setInterval(updateGameArea, 20);
    },
    stop : function() {
        clearInterval(this.interval);
    },    
    clear : function() {
        this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
    }
}

function component(width, height, color, x, y, type) {

    this.type = type;
    this.width = width;
    this.height = height;
    this.speed = 1;
    this.speedX = 0;
    this.speedY = 0;
    this.angle = 0;
    this.x = x;
    this.y = y;    
    this.update = function() {
        ctx = myGameArea.context;
        ctx.save();
        ctx.translate(this.x, this.y);
        ctx.rotate(this.angle);
        ctx.rotate(Math.PI / 6);
        ctx.fillStyle = "yellow";
        ctx.fillRect(this.width / -2, this.height / -2, this.width, this.height);

        ctx.restore();    
    }
    this.newPos = function() {
        this.x += this.speedX;
        this.y += this.speedY;

    }
}

function updateGameArea() {
    myGameArea.clear();
   // myGamePiece.angle += 1 * Math.PI / 180; 
    myGamePiece.newPos();
    myGamePiece.update();
}
function rotate(){
    myGamePiece.speedX += -1;
    myGamePiece.speedY += -1;
}

</script>
 <button onclick="rotate()">HIT</button>
</body>
</html>

如何仅在一侧旋转画布中的矩形到一定程度并重置到其原始位置

如何使用HTML5仅在一侧和另一侧旋转矩形常量

0 个答案: