There are several open source projection mapper projects that run on a RaspPi, or other platforms, here are a few of them:

https://github.com/arisona/mpm

https://ofxpimapper.com/

https://mapmapteam.github.io/

There are media players and graphics generators that will run on a RaspPi also. Finding a bright enough projector and sheltering it for outdoor use might be the main challenge.

Another approach might be a galvo scanned laser with DMX software to control it, though there may be safety/liability issues with that.