I would like to know if it's possible, in C/C++, to launch an application and grab its standard video output?
The goal of this would be to grab the buffer of an application, and use it as a texture for a grid of vertex with special texture coordinate (in order to project it in a FullDome)?
I'm developing under Linux.
Theoretically, it's possible. Is the other application using OpenGL? Or is just any X11 application?
If is just an X11 app, you need to do what a compositing manager does, which is use the COMPOSITE X extension to get window contents, and then process them.
If is just a OpenGL app, and you can modify it, you can use a FBO to draw everything to a texture, and use shared memory (SHM) to share the texture data with the other application.