Spartan HUD
This progaram finds the 3D coordinates of where your gun is pointing and projects a target reticle using Microsoft HoloLens.
Since HoloLens has yet to be released, this is just a console application that calculates the unknown coordinates.
Console Preview
Windows
Open Spartan-HUD.exe
to launch the console application.
Mac
C# programs don't run natively on Macs, so Mono is needed. Download here. Once Mono is installed, open Terminal and run:
mono Spartan-HUD.exe