Overlay the word/number in the Windows game fullscreen (like in Fraps)

Question

I think a lot of people used application "Fraps" for recording video from game. I use it for displaying FPS (frames per second) in the games. Fraps can show digits at the corner of screen when game runs.

I want to display core temperature of processor. The temperature I will find, but I need to khow, how can I display it in the game? (I need it for testing core temperatures in the game, because stress tests of Everest/AIDA64 doesn't much load the system).

Want to use C# (but can listen to all solutions, C++, Java)
Example games: Dirt2, Call of Duty 5 (DirectX)

P.S. This post was similar... c# text/winForm overlay video games like xfire,PIX,steam,fraps etc

Answer 1

What you want to do is a bit more complex than you might think. There are different sources on the web about this, some might be a bit outdated. A good search Term is "Hook direct 3d", there are also other threads on stackoverflow about this topic. A good thread is also this.

One advice: You are changing the runtime code of the game, which can be detected by anti cheat mechanism and can cause banning if the game is a multiplayer game. It is even possible that widely known applications like fraps are on some sort of whitelist against these checks, but i'm not sure about that.

Answer 2

An alternative to what you want could be to make your form always stay on top (form.TopMost = true;). Then you can set the transparency color the same color as your form (by default it would be form.TransparencyKey = System.Drawing.SystemColors.Control;). After that you can remove the border of your form (form.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;).

Be careful not to use the transparency color anywhere else (it'll make part of images transparent if it contains this color).
Make sure to have a way of closing the form. (and moving it if needed).