拼命柯南
2015-11-18 15:17
Cannot read property 'drawImage' of undefined,请问大家如何修复这个bug
function drawBackground()
{
ctx2.drawImage(bgPic,0,0,canWidth,canHeight);
}
这是background.js
var can1;
var can2;
var ctx1;
var ctx2;
var canWidth;
var canHeight;
var lastTime;
var deltaTime;
var bgPic =new Image();
document.body.onload =game;
function game()
{
init;
lastTime =Date.now();
deltaTime =0;
gameloop();
}
function init()
{
//获得canvas context
can1 =document.getElementById("canvas1");//fishes,dust,UI,circle
ctx1 =can1.getContext('2d');
can2 =document.getElementById("canvas2");//background,ane,fruits
ctx2 =can2.getContext('2d');
bgPic.src ="./src/background.jpg";
canWidth =can1.width;
canHeight =can1.height;
}
function gameloop()
{
requestAnimFrame(gameloop);//setInterval,setTimeout,frame per second
var now =Date.now();
deltaTime =now - lastTime;
lastTime =now;
drawBackground();
}
这是main.js
调用这个函数的对像不对吧,把你的代码贴上来吧
HTML5小游戏---爱心鱼(上)
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