I'm recreating World of Warcraft only in 2D using DirectX and I'm trying to simulate this which can be used as a cooldown on a spell that you can't use for a certain number of seconds / minutes. The lit image overlaying rotates smoothly around like a clock over the darkened image.I figured the solution to this would be to split the square into a pie using 8 separate polygons. But my problem is probably in my rotation trigonometry with both the texture coordinates and rotation, cause I can only get one polygon of the 8 to work properly. The others just warp or don't do it right. Is there a solution or a better approach on how I can produce this effect shown below? Thanks in advance. I'm using VB but I can decipher C++ and C# as well if someone has a code sample.