Trying to know if focus application is DirectX / OpenGL

Trying to know if focus application is DirectX / OpenGL

References

Reference NO 1

http://stackoverflow.com/questions/18033536/draw-directx-opengl-graphics-on-an-existing-graphics-application

Reference NO 2

http://programmers.stackexchange.com/questions/60544/why-do-game-developers-prefer-windows

Reference NO 3

http://www.extremetech.com/gaming/133824-valve-opengl-is-faster-than-directx-even-on-windows

Reference NO 4

http://www.awesomenauts.com/forum/viewtopic.php?f=13&t=2735

Reference NO 5

http://blog.wolfire.com/2010/01/Why-you-should-use-OpenGL-and-not-DirectX

Reference NO 6

http://tf2.gamebanana.com/tuts/6903

Reference NO 7

http://www.walkerb.net/blog/dx-1/

Reference NO 8

http://forums.tigsource.com/index.php?topic=30030.0