在Javascript中通过滑块设置值
我是javascript新手,目前正在开发一款乒乓球游戏。 快完成了,我唯一想添加的是一个滑块,它可以改变机器人的移动速度,但是由于某种原因,当我将机器人的速度值设置为滑块的值时,机器人就消失了。 我对机器人击球的角度做了同样的处理,效果很好,所以我不知道为什么另一个滑块不起作用。 代码处于“左拨”功能中 CSS/HTML在Javascript中通过滑块设置值,javascript,slider,Javascript,Slider,我是javascript新手,目前正在开发一款乒乓球游戏。 快完成了,我唯一想添加的是一个滑块,它可以改变机器人的移动速度,但是由于某种原因,当我将机器人的速度值设置为滑块的值时,机器人就消失了。 我对机器人击球的角度做了同样的处理,效果很好,所以我不知道为什么另一个滑块不起作用。 代码处于“左拨”功能中 CSS/HTML body{ width: 100vw; height: 100vh; } <body onresize="resizeCanvas()">
body{
width: 100vw;
height: 100vh;
}
<body onresize="resizeCanvas()">
Bot speed<input type="range" min="0" max="5" step="0.5" value="2.5" id="botSpeed">
<canvas id="canvas"></canvas>
<script>
</script>
</body>
正文{
宽度:100vw;
高度:100vh;
}
机器人速度
JavaScript
var canvas, context;
canvas = document.getElementById("canvas");
context = canvas.getContext("2d");
var ballRadius;
var ballRadiusValue = .000005; // Radius of ball
var ballSpeed = 2.5; // Speed the ball moves with
var ballSpeedX;
var ballSpeedY;
var ballX;
var ballY;
var paddleWidth;
var paddleWidthValue = .01; // Width of paddles
var paddleHeight;
var paddleHeightValue = .125; // Height of paddles
var paddleMargin = .01; // Margin the paddles have from the wall
var paddleLeftX;
var paddleLeftY;
var angle = 5; // Angle the bot hits the ball with (lower number == higher difficulty)
var speed = 2.5; // Speed the bot follows the ball with (higher number == higher difficulty)
// Main function
window.onload = function() {
resizeCanvas();
startGame();
setInterval(drawCanvas, 1);
};
// Resizes the canvas depending on the screen resolution
function resizeCanvas() {
// Sets the canvas width and height to the users viewport
context.canvas.width = document.body.clientWidth;
context.canvas.height = document.body.clientHeight;
// Ball
ballRadius = (canvas.width * canvas.height) * ballRadiusValue;
ballX = (canvas.width / 2) - (ballRadius / 2); // Center of canvas width
ballY = (canvas.height / 2) - (ballRadius / 2); // center of canvas height
// Paddle
paddleWidth = canvas.width * paddleWidthValue;
paddleHeight = canvas.height * paddleHeightValue;
paddleLeftX = canvas.width * paddleMargin;
paddleLeftY = (canvas.height / 2) - (paddleHeight / 2); // Centers, center of paddle to height of canvas
}
// Draws everything that's displayed on the canvas
function drawCanvas() {
background();
paddleLeft();
ball();
ballMovement();
}
function background() {
context.clearRect(0, 0, canvas.width, canvas.height);
context.fillStyle = "transparent";
context.fillRect(0, 0, canvas.width, canvas.height);
}
// Bot
function paddleLeft() {
context.fillStyle = "red";
context.fillRect(paddleLeftX, paddleLeftY, paddleWidth, paddleHeight);
var botSpeed = document.getElementById("botSpeed");
speed = 2.5; // This works
speed = botSpeed.value; // This doesn't work, even though "botSpeed.value" is the same value
var paddleLeftCenter = paddleLeftY + (paddleHeight / 2);
// How fast and at what angle the bot follows the ball
if (paddleLeftCenter < ballY - (paddleHeight / angle) && (paddleLeftY + paddleHeight) <= canvas.height) // Paddle is above ball
{
paddleLeftY += speed; // Moves the paddle down
}
else if (paddleLeftCenter > ballY + (paddleHeight / angle) && paddleLeftY >= 0) // Paddle is below ball
{
paddleLeftY -= speed; // Moves the paddle up
}
}
// Initial speed
function ballMovement() {
ballX += ballSpeedX;
ballY += ballSpeedY;
}
function ball() {
context.fillStyle = "black";
context.beginPath();
context.arc(ballX, ballY, ballRadius, 0, Math.PI * 2, true);
context.fill();
// Collision with border
if (ballX + ballRadius <= 0 ) // Left side
{
resetBall();
}
if (ballY - ballRadius <= 0) // Top
{
ballSpeedY = -ballSpeedY;
}
else if (ballY + ballRadius >= canvas.height) // Bottom
{
ballSpeedY = -ballSpeedY;
}
}
// Moves the ball in a random direction on game start
function startGame() {
ballSpeedX = -ballSpeed;
ballSpeedY = ballSpeed;
var random = Math.random();
if (random <= .5) // Moves ball down
{
ballSpeedY = ballSpeedY;
}
else if (random <= 1) // Moves ball up
{
ballSpeedY = -ballSpeedY;
}
}
// Resets the ball to its original position
function resetBall() {
ballX = canvas.width / 2;
ballY = canvas.height / 2;
startGame();
}
var画布,上下文;
canvas=document.getElementById(“canvas”);
context=canvas.getContext(“2d”);
var球半径;
var ballRadiusValue=.000005;//球的半径
var ballSpeed=2.5;//球移动的速度
var-ballSpeedX;
var-ballSpeedY;
var-ballX;
巴利变种;
宽度;
变量值=.01;//桨叶宽度
高度;
var PappelHeightValue=.125;//桨叶高度
var paddleMargin=.01;//将桨叶与墙隔开
var-leftx;
左撇子;
变量角度=5;//机器人击球角度(数字越低=难度越高)
var速度=2.5;//机器人跟随球的速度(更高的数字=更高的难度)
//主要功能
window.onload=函数(){
调整画布的大小();
startGame();
设置间隔(drawCanvas,1);
};
//根据屏幕分辨率调整画布大小
函数resizeCanvas(){
//设置“用户”视口的画布宽度和高度
context.canvas.width=document.body.clientWidth;
context.canvas.height=document.body.clientHeight;
//球
ballRadius=(canvas.width*canvas.height)*ballRadiusValue;
ballX=(canvas.width/2)-(ballRadius/2);//画布宽度的中心
ballY=(canvas.height/2)-(ballRadius/2);//画布高度的中心
//划桨
桨叶宽度=canvas.width*桨叶宽度值;
桨叶高度=canvas.height*桨叶高度值;
PappelLeftX=canvas.width*PapperMargin;
桨左=(canvas.height/2)-(桨高/2);//中心,桨中心到画布高度
}
//绘制画布上显示的所有内容
函数drawCanvas(){
背景();
左();
ball();
球运动();
}
函数背景(){
clearRect(0,0,canvas.width,canvas.height);
context.fillStyle=“透明”;
context.fillRect(0,0,canvas.width,canvas.height);
}
//机器人
函数左(){
context.fillStyle=“红色”;
fillRect(paileleftx、pailelefty、pailewidth、paileheight);
var botSpeed=document.getElementById(“botSpeed”);
速度=2.5;//这是可行的
speed=botSpeed.value;//这不起作用,即使“botSpeed.value”是相同的值
var BALLETLEFTCENTER=BALLETLEFTY+(桨叶高度/2);
//机器人跟踪球的速度和角度有多快
如果(桨叶左中<球-(桨叶高度/角度)&&(桨叶左中+桨叶高度)球+(桨叶高度/角度)&&桨叶左中>=0)//桨叶位于球下方
{
桨左-=速度;//将桨向上移动
}
}
//初速度
函数ballMovement(){
ballX+=ballSpeedX;
ballY+=ballY;
}
函数球(){
context.fillStyle=“黑色”;
context.beginPath();
弧(ballX,ballY,ballRadius,0,Math.PI*2,true);
context.fill();
//与边界的碰撞
如果(ballX+ballRadius正常,我就让它工作了。
由于某些原因,我不能只设置新值,我必须减去/添加它们
这是新代码
var isMovingSlider = false; // Slider function will only get fired once on change
if (!isMovingSlider)
{
// Sets the "botSpeed" value
botSpeed.addEventListener("change", function () {
isMovingSlider = true;
if (botSpeed.value < 2.5)
{
// For every step the slider gets moved below 2.5, subtract 0.5 from "speed"
speed = 2.5;
speed -= (2.5 - botSpeed.value);
}
else if (botSpeed.value > 2.5)
{
// For every step the slider gets moved aboce 2.5, add 0.5 to "speed"
speed = 2.5;
speed += (botSpeed.value - 2.5);
}
else if (botSpeed.value == 2.5)
{
speed = 2.5;
}
});
isMovingSlider = false;
}
botSpeedValue.innerHTML = botSpeed.value; // Displays the value of "botSpeed"
var isMovingSlider=false;//Slider函数仅在发生更改时触发一次
如果(!isMovingSlider)
{
//设置“机器人速度”值
botSpeed.addEventListener(“更改”,函数(){
isMovingSlider=true;
如果(速度值<2.5)
{
//滑块每移动一步低于2.5,从“速度”中减去0.5
速度=2.5;
速度-=(2.5-机器人速度值);
}
否则如果(botSpeed.value>2.5)
{
//滑块每移动2.5步,将“速度”增加0.5
速度=2.5;
速度+=(机器人速度值-2.5);
}
否则如果(botSpeed.value==2.5)
{
速度=2.5;
}
});
isMovingSlider=false;
}
botSpeedValue.innerHTML=botSpeed.value;//显示“botSpeed”的值
<代码> >“BOT刚刚消失”——你在控制台中有什么错误吗?BTW,JSFiddle不适合我,所以考虑把代码本身作为问题。