I'm developing a 3D tower defense-like game in C++/OpenGL on Windows.
The problem I'm having isn't about the game itself (the game runs fine), but it's about using screen recording software to record gameplay.
For some reason, whenever I try to record the screen (I've tried both Camtasia Studio 8 and Fraps 3.5.9), it slows down the game (I'm not talking about just an FPS drop; the actual game timers run slower).
To show an example of what I mean, see the following screenshot: I ran two instances of my game at once (side by side), and recorded the righthand one using Fraps. As you can see in the image below, Fraps is causing the game time for the recorded instance to increase almost twice as slowly as it should.
I'm getting around 800-1000 FPS when running the game without Fraps recording, and around 300-400 FPS with Fraps recording. But playing the game with recording causes everything to happen in slow-motion, despite it running smoothly rendering-wise.
For timing I've tried using both the
timeGetTime() approaches - the slowdown still occurs using either.
Does anyone have an idea what might be causing this? Could it be because of the way I'm rendering with OpenGL?