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我做了一个像乒乓球一样的游戏,我想用箭头键而不是鼠标来控制 Racket 。
出于某种原因,游戏未检测到按键。另外,我尝试添加按P时暂停游戏功能,但我也卡在了这个上。
有人可以帮忙吗?
事件监听器的声明:
document.addEventListener('keydown', event => {
if (event.keyCode === 38) {
paddle1 += 5;
} else if (event.keyCode === 40) {
paddle1 -= 5;
} else if (event.keycode === 80) {
PausePressed;
}
});
Here's the full pong game with keyboard controls:
var canvas;
var canvasContext;
var ballX = 50;
var ballSpeedX = 10;
var ballY = 50;
var ballSpeedY = 5;
var ym = 10; // the movement of y axis
var keys = new Array();
var player1Score = 0;
var player2Score = 0;
const WinningScore = 5;
var showingWinScreen = false;
var paddle1 = 350;
var paddle2 = 350;
const paddleHeight = 100;
const paddleThickness = 10;
function PausePressed(evt) {
if(showingWinScreen) {
player1Score = 0;
player2Score = 0;
showingWinScreen = false;
}
}
window.onload =function() {
canvas = document.getElementById('Mycanvas');
canvasContext = canvas.getContext('2d');
window.addEventListener('keydown',doKeyDown,true);
window.addEventListener('keyup',doKeyUp,true);
var framesPerSecond = 60;
setInterval(function() {
moveEverything();
drawEverything();
}, 1000/framesPerSecond);
}
function ballReset(){
if(player1Score >= WinningScore ||
player2Score >= WinningScore) {
showingWinScreen = true;
}
ballX = canvas.width/3;
ballY = canvas.height/3;
ballSpeedX = -ballSpeedX
}
function doKeyDown(evt){
keys[evt.keyCode] = true;
evt.preventDefault(); // Prevents the page to scroll up/down while pressing arrow keys
}
function doKeyUp(evt) {
keys[evt.keyCode] = false;
}
function move() {
if (38 in keys && keys[38]){ //up
paddle1 += ym;
}
if (40 in keys && keys[40]){ //down
paddle1 -= ym;
}
}
function computerMovement() {
var paddle2Center = paddle2 + (paddleHeight/2);
if(paddle2Center < ballY - 30) {
paddle2 = paddle2 + 8;
} else if(paddle2Center > ballY + 30) {
paddle2 = paddle2 - 8;
}
}
function moveEverything(){
if(showingWinScreen) {
return;
}
computerMovement();
ballX = ballX + ballSpeedX;
ballY = ballY + ballSpeedY;
if(ballX > canvas.width) {
if(ballY > paddle2 &&
ballY < paddle2+paddleHeight) {
ballSpeedX = -ballSpeedX;
var deltaY = ballY
-(paddle2+paddleHeight/2);
ballSpeedY = deltaY * 0.25;
} else {
player1Score += 1;
ballReset();
}
}
if(ballX < 0) {
if(ballY > paddle1 &&
ballY < paddle1+paddleHeight) {
ballSpeedX = -ballSpeedX;
var deltaY = ballY
-(paddle1+paddleHeight/2);
ballSpeedY = deltaY * 0.25;
} else {
player2Score += 1;
ballReset();
}
}
if(ballY > canvas.height) {
ballSpeedY = -ballSpeedY
}
if(ballY < 0) {
ballSpeedY = -ballSpeedY
}
}
function drawNet() {
for(var i=0;i<canvas.height; i+=40) {
colorRect(canvas.width/2-1,i,2,20,'white');
}
}
function drawEverything() {
colorRect(0,0,canvas.width,canvas.height,'black');
if(showingWinScreen) {
canvasContext.fillStyle = 'white';
if(player1Score >= WinningScore) {
canvasContext.font = 'italic 60pt Calibri';
canvasContext.fillText('Left Player Won!', 475,350);
} else if(player2Score >= WinningScore) {
canvasContext.font = 'italic 60pt Calibri';
canvasContext.fillText('Right Player Won', 475,350);
}
canvasContext.font = 'italic 80pt Calibri';
canvasContext.fillText('click to continue', 400,600);
return;
}
drawNet();
colorRect(0,paddle1,paddleThickness,paddleHeight,'white');
colorRect(canvas.width-paddleThickness,paddle2,paddleThickness,paddleHeight,'white');
colorCircle(ballX, ballY, 10, 'white')
canvasContext.fillText(player1Score, 100,100);
canvasContext.fillText(player2Score, canvas.width-100,100);
}
function colorRect(leftX,topY, width, height, drawColor) {
canvasContext.fillStyle = drawColor;
canvasContext.fillRect(leftX,topY, width,height);
}
function colorCircle(centerX, centerY, radius, drawColor) {
canvasContext.fillStyle = drawColor;
canvasContext.beginPath();
canvasContext.arc(centerX, centerY, radius, 0,Math.PI*2, true);
canvasContext.fill();
}
init();
<html>
<head>
<title>Ping Pong Game</title>
</head>
<body bgcolor="#FFB630">
<canvas id="Mycanvas" width="1600" height="800"></canvas>
<div>
<h1>The Ping Pong Game</h1>
<h2>Use the mouse to control the paddle!</h2>
</div>
</body>
</html>
And here's the original game with mouse control
var canvas;
var canvasContext;
var ballX = 50;
var ballSpeedX = 10;
var ballY = 50;
var ballSpeedY = 5;
var player1Score = 0;
var player2Score = 0;
const WinningScore = 5;
var showingWinScreen = false;
var paddle1 = 350;
var paddle2 = 350;
const paddleHeight = 100;
const paddleThickness = 10;
function calculateMousePos(evt) {
var rect = canvas.getBoundingClientRect();
var root = document.documentElement;
var mouseX = evt.clientX - rect.left - root.scrollLeft;
var mouseY = evt.clientY - rect.top - root.scrollTop;
return {
x: mouseX,
y: mouseY
}
}
function handleMouseClick(evt) {
if (showingWinScreen) {
player1Score = 0;
player2Score = 0;
showingWinScreen = false;
}
}
window.onload = function() {
canvas = document.getElementById('Mycanvas');
canvasContext = canvas.getContext('2d');
var framesPerSecond = 60;
setInterval(function() {
moveEverything();
drawEverything();
}, 1000 / framesPerSecond);
canvas.addEventListener('mousedown', handleMouseClick);
canvas.addEventListener('mousemove',
function(evt) {
var mousePos = calculateMousePos(evt);
paddle1 = mousePos.y - (paddleHeight / 2);
});
}
function ballReset() {
if (player1Score >= WinningScore ||
player2Score >= WinningScore) {
showingWinScreen = true;
}
ballX = canvas.width / 3;
ballY = canvas.height / 3;
ballSpeedX = -ballSpeedX
}
function computerMovement() {
var paddle2Center = paddle2 + (paddleHeight / 2);
if (paddle2Center < ballY - 30) {
paddle2 = paddle2 + 8;
} else if (paddle2Center > ballY + 30) {
paddle2 = paddle2 - 8;
}
}
function moveEverything() {
if (showingWinScreen) {
return;
}
computerMovement();
ballX = ballX + ballSpeedX;
ballY = ballY + ballSpeedY;
if (ballX > canvas.width) {
if (ballY > paddle2 &&
ballY < paddle2 + paddleHeight) {
ballSpeedX = -ballSpeedX;
var deltaY = ballY -
(paddle2 + paddleHeight / 2);
ballSpeedY = deltaY * 0.25;
} else {
player1Score += 1;
ballReset();
}
}
if (ballX < 0) {
if (ballY > paddle1 &&
ballY < paddle1 + paddleHeight) {
ballSpeedX = -ballSpeedX;
var deltaY = ballY -
(paddle1 + paddleHeight / 2);
ballSpeedY = deltaY * 0.25;
} else {
player2Score += 1;
ballReset();
}
}
if (ballY > canvas.height) {
ballSpeedY = -ballSpeedY
}
if (ballY < 0) {
ballSpeedY = -ballSpeedY
}
}
function drawNet() {
for (var i = 0; i < canvas.height; i += 40) {
colorRect(canvas.width / 2 - 1, i, 2, 20, 'white');
}
}
function drawEverything() {
colorRect(0, 0, canvas.width, canvas.height, 'black');
if (showingWinScreen) {
canvasContext.fillStyle = 'white';
if (player1Score >= WinningScore) {
canvasContext.font = 'italic 60pt Calibri';
canvasContext.fillText('Left Player Won!', 475, 350);
} else if (player2Score >= WinningScore) {
canvasContext.font = 'italic 60pt Calibri';
canvasContext.fillText('Right Player Won', 475, 350);
}
canvasContext.font = 'italic 80pt Calibri';
canvasContext.fillText('click to continue!', 400, 600);
return;
}
drawNet();
colorRect(0, paddle1, paddleThickness, paddleHeight, 'white');
colorRect(canvas.width - paddleThickness, paddle2, paddleThickness, paddleHeight, 'white');
colorCircle(ballX, ballY, 10, 'white')
canvasContext.fillText(player1Score, 200, 100);
canvasContext.fillText(player2Score, canvas.width - 200, 100);
}
function colorRect(leftX, topY, width, height, drawColor) {
canvasContext.fillStyle = drawColor;
canvasContext.fillRect(leftX, topY, width, height);
}
function colorCircle(centerX, centerY, radius, drawColor) {
canvasContext.fillStyle = drawColor;
canvasContext.beginPath();
canvasContext.arc(centerX, centerY, radius, 0, Math.PI * 2, true);
canvasContext.fill();
}
<html>
<head>
<title>Ping Pong Game</title>
</head>
<body>
<canvas id="Mycanvas" width="1600" height="800"></canvas>
<div>
<h1>The Ping Pong Game</h1>
<h2>Use the mouse to control the paddle!</h2>
</div>
<style>
body {
background-color: #FFD700;
}
</style>
</body>
</html>
最佳答案
因此,最大的问题是您从未调用过move()
函数。我向您的 keydown
事件添加了对 move()
函数的调用,然后不断地在控制台记录发生的一切,直到我找出问题所在。
这是我编辑过的代码(我留下了 console.logs 来向您展示我是如何调试它的)。它显示桨在正确的方向移动。
您可能还会遇到按住键时延迟拨片移动的问题,因为需要一秒钟的时间来记录该键是被按住而不是被按下。我附上了 JS eventhandler帮助您找到解决方法的引用。
您还需要单击页面以使其成为焦点。
var canvas;
var canvasContext;
var ballX = 50;
var ballSpeedX = 10;
var ballY = 50;
var ballSpeedY = 5;
var ym = 10; // the movement of y axis
var keys = new Array();
var player1Score = 0;
var player2Score = 0;
const WinningScore = 11115;
var showingWinScreen = false;
var paddle1 = 350;
var paddle2 = 350;
const paddleHeight = 100;
const paddleThickness = 10;
function PausePressed(evt) {
if (showingWinScreen) {
player1Score = 0;
player2Score = 0;
showingWinScreen = false;
}
}
window.onload = function() {
canvas = document.getElementById('Mycanvas');
canvasContext = canvas.getContext('2d');
window.addEventListener('keydown', doKeyDown, true);
window.addEventListener('keyup', doKeyUp, true);
var framesPerSecond = 60;
setInterval(function() {
moveEverything();
drawEverything();
}, 1000 / framesPerSecond);
}
function ballReset() {
if (player1Score >= WinningScore ||
player2Score >= WinningScore) {
showingWinScreen = true;
}
ballX = canvas.width / 3;
ballY = canvas.height / 3;
ballSpeedX = -ballSpeedX
}
function doKeyDown(evt) {
keys[evt.keyCode] = true;
console.log("current keyCode:",evt.keyCode)
move()
evt.preventDefault(); // Prevents the page to scroll up/down while pressing arrow keys
}
function doKeyUp(evt) {
console.log("'key up' event fired")
console.log(`keyCode: ${evt.keyCode} keys: ${keys}`)
console.log(" 'key[evt.keyCode]' before:", keys[evt.keyCode])
keys[evt.keyCode] = false;
console.log(" 'key[evt.keyCode]' after:", keys[evt.keyCode])
console.log(`keyCode: ${evt.keyCode} keys: ${keys}`)
}
function move() {
console.log("Entered move function")
if (38 in keys && keys[38]) { //up
console.log("entered '38 in keys'. UP ")
console.log("paddle1 before -= :", paddle1)
paddle1 -= ym;
console.log("paddle1 after -= :", paddle1)
}
else if (40 in keys && keys[40]) { //down
console.log("entered '40 in keys'. DOWN ")
console.log("paddle1 before += :", paddle1)
paddle1 += ym;
console.log("paddle1 after += :", paddle1)
}
}
function computerMovement() {
var paddle2Center = paddle2 + (paddleHeight / 2);
if (paddle2Center < ballY - 30) {
paddle2 = paddle2 + 8;
} else if (paddle2Center > ballY + 30) {
paddle2 = paddle2 - 8;
}
}
function moveEverything() {
if (showingWinScreen) {
return;
}
computerMovement();
ballX = ballX + ballSpeedX;
ballY = ballY + ballSpeedY;
if (ballX > canvas.width) {
if (ballY > paddle2 &&
ballY < paddle2 + paddleHeight) {
ballSpeedX = -ballSpeedX;
var deltaY = ballY -
(paddle2 + paddleHeight / 2);
ballSpeedY = deltaY * 0.25;
} else {
player1Score += 1;
ballReset();
}
}
if (ballX < 0) {
if (ballY > paddle1 &&
ballY < paddle1 + paddleHeight) {
ballSpeedX = -ballSpeedX;
var deltaY = ballY -
(paddle1 + paddleHeight / 2);
ballSpeedY = deltaY * 0.25;
} else {
player2Score += 1;
ballReset();
}
}
if (ballY > canvas.height) {
ballSpeedY = -ballSpeedY
}
if (ballY < 0) {
ballSpeedY = -ballSpeedY
}
}
function drawNet() {
for (var i = 0; i < canvas.height; i += 40) {
colorRect(canvas.width / 2 - 1, i, 2, 20, 'white');
}
}
function drawEverything() {
colorRect(0, 0, canvas.width, canvas.height, 'black');
if (showingWinScreen) {
canvasContext.fillStyle = 'white';
if (player1Score >= WinningScore) {
canvasContext.font = 'italic 60pt Calibri';
canvasContext.fillText('Left Player Won!', 475, 350);
} else if (player2Score >= WinningScore) {
canvasContext.font = 'italic 60pt Calibri';
canvasContext.fillText('Right Player Won', 475, 350);
}
canvasContext.font = 'italic 80pt Calibri';
canvasContext.fillText('click to continue', 400, 600);
return;
}
drawNet();
colorRect(0, paddle1, paddleThickness, paddleHeight, 'white');
colorRect(canvas.width - paddleThickness, paddle2, paddleThickness, paddleHeight, 'white');
colorCircle(ballX, ballY, 10, 'white')
canvasContext.fillText(player1Score, 100, 100);
canvasContext.fillText(player2Score, canvas.width - 100, 100);
}
function colorRect(leftX, topY, width, height, drawColor) {
canvasContext.fillStyle = drawColor;
canvasContext.fillRect(leftX, topY, width, height);
}
function colorCircle(centerX, centerY, radius, drawColor) {
canvasContext.fillStyle = drawColor;
canvasContext.beginPath();
canvasContext.arc(centerX, centerY, radius, 0, Math.PI * 2, true);
canvasContext.fill();
}
<html>
<head>
<title>Ping Pong Game</title>
</head>
<body bgcolor="#FFB630">
<canvas id="Mycanvas" width="1600" height="800"></canvas>
<div>
<h1>The Ping Pong Game</h1>
<h2>Use the mouse to control the paddle!</h2>
</div>
</body>
</html>
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