canvas.toDataURL() returns a black image

Question

We are developing a sample three.js application which shows a thumbnail. For any scene that we create, we require to take a screenshot of the canvas, for this purpose, we are using canvas.toDataURL("image/png"). For repeated invocations of the above function, it returns the same black image, despite elements being added to the canvas.

We are using WebGLRenderer and threejs r99

I am using google chrome and threejs. Since the canvas context will be made by threejs itself, I cannot add that parameter (preserveDrawingBuffer) shown in the question Canvas toDataURL() returns blank image only in Firefox

Answer 1

When you are calling WebGLRenderer, pass preserveDrawingBuffer:true. Here are list of parameters which you can configure.