Question

我正在尝试创建一个用于画布游戏的简单Sprite类，但是我在创建类的新实例时指定的图像从不调用onload或onerror。发生了什么，如何让它加载并绘制图像？

这是脚本：

var cvs = document.getElementById("c");
var ctx = cvs.getContext("2d");
var imagesToLoad = 1 ;
var imagesLoaded = 0;
var gameState = 0;
//START OF IMAGE STUFF//
function imageOnload() {
    imagesLoaded+=1;
    console.log("Images: loaded "+imagesLoaded+" overall.");
}
function loadLoop() {
    if (imagesLoaded == imagesToLoad) {
        gameState = 1;
    }
}
function loop1() {
    ctx.drawImage(circle.image);
}
function gameLoop() {
    if(gameState==0){
        loadLoop();
    }
    if(gameState==1){
        loop1();
    }
}

function Sprite(positionsArray){
    this.x = positionsArray[0];
    this.y = positionsArray[1];
    this.dx = positionsArray[2];
    this.dy = positionsArray[3];
    this.angle = positionsArray[4];
    this.rotating = positionsArray[5];


};
circle = new Sprite(new Array(0, 0, 0, 0, 0, 0));
circle.image = new Image().onload="imageOnload()".src="circle.png".onerror="console.log(\"Nope.\")";
console.log("circle?");
setInterval(function(){gameLoop()}, 10);
//END OF IMAGE STUFF//

Answer 1

更正：

image.onload函数定义没有引号
image.onload function definition
image.onerror需要函数定义或匿名函数
在image.src

以下是一些示例代码：

circle.image=new Image();
circle.image.onload=imageOnLoad;
circle.image.onerror=function(){console.log("Image failed to load")};
circle.image.src="koolaidman.png";

function imageOnLoad(){
    ctx.drawImage(circle.image,0,0);  // or do other stuff
}

Javascript Image（）无法加载或绘制

1 个答案: