Concave polygon

Question

To draw complex concave polygons using OpenGL, is it better to decrypt it into triangles or use a screen buffer ? I assume that the stencil buffer will be faster for one frame, but triangulation will be better for several frames if the polygon does not change. However, I have not really tried, so I don’t know.

Answer 1

This is exactly how you said it:

Triangulated polygons render faster, but have a high lump sum CPU cost, namely triangulation. In my experience, it pays for triangulating polygons if you have to do this at least twice.

However, the size of the polygon matters. Very small polygons cost a lot less if you use the stencil buffer method than large polygons because you can limit the size of the second render to the border of the polygon.