This is a paid asset, but now you can download Projector Simulator Free.
Detail this asset from Unity Store: Original Link
Projector Simulator v1.52 (Latest version)
Accurately simulates video projectors to enable images, videos, and RenderTextures to be projected realistically.
Project any image
Project Images, RenderTextures, and Video files in real-time
Optimised
Custom shader-based implementation (2017.4 and later)
Adjustable projector resolution for optimal performance
Most if not all platforms should support the new shader. There is a CPU-based fallback just in case.
Realistic
Adjustable lens shift, aspect ratio, lens ratio, brightness, keystone
Enjoy realistic shadowing – no more fake light sources!
HDRP support (2018.4 and later, see video)
Easy to use
Drag-and-drop usage
C# functions for controlling playback
Support
See the tutorial videos or get in touch on the forum thread or via email.
If you work with real projectors, you may want to consider
Projector Simulator Pro.