Embarcadero MVP Paul Toth has a video up demoing how to build a Google Cardboard VR app with Delphi FireMonkey. Source code is also available. The video is in French so you can use the auto translated subtitles if needed. The video itself talks about building the stereo view, creating the lens distortion effect, and integrating the rotation vector information.
The source code has a number of demos which include StereoView (Demonstration of the Stereo effect), LensEffect (Demonstration of the Lens Distortion effect), NativeSensor (How to read Android Native ROTATION_VECTOR), and FullDemo (Put everything in a single application). The language used in the demos is Object Pascal but could probably be done in C++Builder as well.
Check out the full blog post here or watch the video for yourself below.