Check if object is all painted
I have a brown sprite, which contains a hole with triangular shape.
I've added a trail renderer (and set its order in layer to appear behind the sprite), so the user can paint the sprite's hole without painting the sprite itself.
My question is: how can it detect when the hole is all painted?
I thought about using a shader to check if there is any black pixel in the screen, but I don't know if it's possible, because the shader won't know in what percentage of the image it is.
One way would be to take a screenshot with the ScreenCapture.CaptureScreenshotAsTexture method and then loop through an array of pixel colors from Texture2D.GetPixels32. You could then check if the array contains 'black' pixels.
I would do it in a coroutine for better performance as doing it every frame may slow down your application. Also what is important when it comes to CaptureScreenshotAsTexture according to unity docs:
To get a reliable output from this method you must make sure it is called once the frame rendering has ended, and not during the rendering process. A simple way of ensuring this is to call it from a coroutine that yields on WaitForEndOfFrame. If you call this method during the rendering process you will get unpredictable and undefined results.