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シェイプをキャンバス全体にアニメーション化してエッジを叩いた後に跳ね返そうとしていますが、私のボールのように他の2つの図形に速度がないのは不明です。以下のコードを投稿します。JavaScriptで図形をアニメーション化する
<html>
<body>
<section>
<div>
<canvas id="canvas" width="700" height="300"></canvas>
</div>
<script type="text/javascript">
var canvas,
context,
x = Math.floor((Math.random() * 400) + 1), //Ball x coordinate
y = Math.floor((Math.random() * 300) + 1), //Ball y coordinate
dx = Math.floor((Math.random() * 10) + 1), //X velocity
dy = Math.floor((Math.random() * 4) + 1), //Y velocity
width = 700, //Width of the background
height = 300; //Height of the background
function drawCircle(x,y,r) { //Draws the ball
context.beginPath();
context.arc(x, y, r, 0, Math.PI*2, true);
context.fill();
}
function drawRect(x,y,w,h) { //Draws the background
context.beginPath();
context.rect(x,y,w,h);
context.closePath();
context.fill();
}
function start() { //Runs when the window loads. Stores canvas and context in variables. Runs "draw" on an interval of 10ms
canvas = document.getElementById("canvas");
context = canvas.getContext("2d");
return setInterval(draw, 10);
}
function drawSquare(){
var canvas = document.getElementById('canvas');
if (canvas.getContext){
var ctx = canvas.getContext('2d');
ctx.fillStyle = "white";
ctx.beginPath();
ctx.moveTo(200,50);
ctx.lineTo(250,50);
ctx.lineTo(300, 100);
ctx.lineTo(250,25);
ctx.fill();
}
}
function drawTri(){
var canvas = document.getElementById('canvas');
if (canvas.getContext){
var ctx = canvas.getContext('2d');
ctx.beginPath();
ctx.moveTo(75,50);
ctx.lineTo(100,75);
ctx.lineTo(75,25);
ctx.fill();
}
}
function draw() {
context.clearRect(0, 0, width, height); //Clears the drawing space
context.fillStyle = "black"; //Sets fillstyle to black (for the background)
drawRect(0,0, width, height); //Draws the background
context.fillStyle = "white"; //Sets fillstyle to white (for the ball)
drawCircle(x, y, 10);
drawTri();
drawSquare(); //Calls function to draw the ball
if (x + dx > width || x + dx < 0) //If the ball would leave the width (right or left) on the next redraw...
dx = -dx; //reverse the ball's velocity
if (y + dy > height || y + dy < 0) //If the ball would leave the height (top or bottom) on the next redraw...
dy = -dy; //reverse the ball's velocity
x += dx; //Increase ball x speed by velocity
y += dy; //Increase ball y speed by velocity
}
window.onload = start; //Run "start" function after the window loads
</script>
</section>
</body>
</html>