c # – Representation of the template? – Stack Exchange game development

I may not be looking for this correctly, but I can not seem to find a decent tutorial on what I would like to achieve. The only thing that seems to be close is this tutorial on reflections using the template buffer. However, I have difficulty understanding how I can perform the effect in 2D space for a loading screen. Take the following image as an example:

Loading GIF

I could make some smoke and mirrors to achieve something similar by creating a basic image with a non-transparent background and then making a FillRectangle Call from the 2D context object to increase the fill.

However, in my opinion, there is a way to do this with the template buffer and specify how the template should look rather than just a box.


Notes

  • I can understand the C ++ code if that is the language with which you feel comfortable.

Question

How do I specify the appearance of my template and render it in a 2D space?