Canvas保存纹理到图片

 var MIME_TYPE = "image/png";
 var imgURL = canvas.toDataURL(MIME_TYPE);
 var dlLink = document.createElement(‘a‘);
 dlLink.download = "d://image"+Math.random()+".png";
 dlLink.href = imgURL;
 dlLink.dataset.downloadurl = [MIME_TYPE, dlLink.download, dlLink.href].join(‘:‘);

 document.body.appendChild(dlLink);
 dlLink.click();
 document.body.removeChild(dlLink);