Realistic Online is a tool that lets you see the reflection of the environment in real time. It's a straightforward mod that supports Grand Theft Auto V.

Installation Instructions:

To install it, you need to download the mod.
Select Reshade Setup 4.5.4.exe in the folder to install it in the game folder with Direct 3D 10/11/12.
Copy all the files from the graphic mod folder to your GTA game folder, then hit the replace all button.
Start the game, and then press F12 to access the reshade menu.