R – FPS how calculate this

I'm getting roughly 5.600 FPS with an empty display loop (GeForce 260 GTX, 1920x1080). Adding glClear lowers it to 4.000 FPS which is still way over 200... A simple graphics engine (AoE2 style) should run at about 100-200 FPS (GeForce 8 or similar). Probably more if it's multi-threaded and fully optimized.

I don't know what exactly you do in your loop or what hardware that is running on, but 200 FPS sounds like you are doing something else besides drawing nothing (sleep? game logic stuff? greedy framework? Aero?). The swapbuffer function should not take 5ms even if both framebuffers have to be copied. You can use a profile to check where the most CPU time is spent (timing results from gl* functions are mostly useless though)

If you are doing something with OpenGL (drawing stuff, creating textures, etc.) there is a nice extension to measure times called GL_EXT_timer_query.

Some general optimization tips:

• don't use immediate mode (glBegin/glEnd), use VBO and/or display lists+vertex arrays instead
• use some culling technique to remove objects outside your view (opengl would have to cull every polygon separately)
• try minimizing state changes, especially changing the bound texture or vertex buffer

Shawn Hargreaves has a great post about this here. The first difference I see between his code and yours is the fact that you reset your elapseTime to 0 each time, which will lose some time, whereas Shawn just subtracts 1 second from his elapsedTime. Also, Shawn uses ElapsedGameTime instead of ElapsedRealTime. He updates his frameCounter in the Draw function instead of the Update function as well.

As far as why he uses ElapsedRealTime, he explains it in a comment after the post:

> Surely 1 / gameTime.ElapsedRealTime.TotalSeconds

> will therefore give the current framerate.

That will tell you how long it was since the previous call to Update, but that is not the same thing as your framerate!

a) If the game is dropping frames, Update will be called more frequently in order to catch up. You want to time the number of actual draws that are taking place, not just these extra catch-up logic frames.

b) The time for a single Update can fluctuate widely, so the figure you get out of that will be too flickery to be easily readable.

I would try his component, and see if it works for you. The post is pretty old, and I think you will have to change LoadGraphicsContent to LoadContent and UnloadGraphicsContent to UnloadContent, as another one of the comments points out.