Javascript 我不知道';“我不想要我的”;“玩家”;要离开屏幕,如何防止出现这种情况?
这是我的JavaScript。在底部附近,您将看到一个用于keydown事件的addEventListener。在该函数中,存在键控代码。该代码被包装在一个if函数中,if函数中包含的内容阻止播放器离开画布Javascript 我不知道';“我不想要我的”;“玩家”;要离开屏幕,如何防止出现这种情况?,javascript,html,canvas,keydown,Javascript,Html,Canvas,Keydown,这是我的JavaScript。在底部附近,您将看到一个用于keydown事件的addEventListener。在该函数中,存在键控代码。该代码被包装在一个if函数中,if函数中包含的内容阻止播放器离开画布 function initCanvas() { var canvas = document.getElementById('my_canvas'); var ctx = canvas.getContext('2d'); var cW = ctx.canvas.widt
function initCanvas() {
var canvas = document.getElementById('my_canvas');
var ctx = canvas.getContext('2d');
var cW = ctx.canvas.width;
var cH = ctx.canvas.height;
var dist = 10;
function Player() {
this.x = 0, this.y = 0, this.w = 50, this.h = 50;
this.render = function() {
ctx.fillStyle = "orange";
ctx.fillRect(this.x, this.y, this.w, this.h);
}
}
var player = new Player();
player.x = 100;
player.y = 225;
function animate() {
ctx.fillStyle = '#000';
ctx.fillRect(0, 0, canvas.width, canvas.height);
player.render();
}
var animateInterval = setInterval(animate, 30);
document.addEventListener('keydown', function(event) {
var key_press = String.fromCharCode(event.keyCode);
if (//I don't know what should go here) {
if (key_press == "W") {
player.y -= dist;
} else if (key_press == "S") {
player.y += dist;
} else if (key_press == "A") {
player.x -= dist;
} else if (key_press == "D") {
player.x += dist;
}
}
});
}
window.onload = initCanvas();
document.addEventListener('keydown',函数(事件){
var key_press=String.fromCharCode(event.keyCode);
if(//我不知道这里应该放什么){
如果(按键按下==“W”和&player.y>=距离){
player.y-=距离;
}else if(按键=S和播放器y=距离){
player.x-=距离;
}否则如果(按键按下==“D”和&player.x<(cW-dist)){
player.x+=距离;
}
}
});
额外检查将检查他是否不在画布边缘,也不在距离画布边缘
的位置假设左上角为(0,0)。
请注意,当用户与画布保持一定距离时,最好将其移动到画布边缘。我将把这件事留给你。明确检查他是否不在屏幕边缘(也不在距离边缘
document.addEventListener('keydown', function(event) {
var key_press = String.fromCharCode(event.keyCode);
if (//I don't know what should go here) {
if (key_press == "W" && player.y >= dist) {
player.y -= dist;
} else if (key_press == "S" && player.y <= (cH - dist)) {
player.y += dist;
} else if (key_press == "A" && player.x >= dist) {
player.x -= dist;
} else if (key_press == "D" && player.x < (cW - dist)) {
player.x += dist;
}
}
});