[英]canvas keyPress movement - broken
我的keyPress運動似乎被破壞了,如果我兩次按下arr.up / down,那么它就被破壞了,並且我無法將元素移回去。 當我停止按住arr.up / down時,元素甚至都沒有停止,為什么?
rocket = new Image();
x = 50;
y = 185;
score = 0;
velY = 0;
speed = 2;
y += velY;
ctx.drawImage(rocket, x, y);
if(e.keyCode == 38) {
if(velY < speed) {
velY --;
}
}
if(e.keyCode == 40) {
if(velY < speed) {
velY ++;
}
}
預覽: http : //game.stranger.tk/
我會編輯您的代碼,但是通過您的鏈接進行的游戲不起作用:(。我希望我提供的此代碼示例對您有所幫助。
jsFiddle: https ://jsfiddle.net/w1z2c1cq/
javascript
var c = document.getElementById('myCanvas');
var ctx = c.getContext('2d');
var rocket = function()
{
this.Sprite = new Image();
this.Sprite.src = "https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcS9zafp1ezdR2lSAxTdjZYe_nPhe6VeKKmAuK-GzWQCSs395WkzNA";
this.XPos = 100;
this.YPos = 100;
}
var player = new rocket();
setInterval(function()
{
ctx.fillRect(0,0,400,400);
ctx.drawImage(player.Sprite, player.XPos, player.YPos);
}, 3);
window.addEventListener("keydown", function(e){
// Left key
if(e.keyCode === 37) {
player.XPos -= 5;
}
// Right key
if(e.keyCode === 39) {
player.XPos += 5;
}
// Up key
if(e.keyCode === 38) {
player.YPos -= 5;
}
// Down key
if(e.keyCode === 40) {
player.YPos += 5;
}
});
同樣在您的代碼中,您正在檢查上下if(velY < speed)
相同的if語句if(velY < speed)
嘗試
// Up
if(e.keyCode == 38) {
if(velY < speed) {
velY --;
}
}
// Down
if(e.keyCode == 40) {
if(velY > -speed) {
velY ++;
}
}
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