How to implement a film grain overlay?

[sly pulsar]

I intend on adding a toggleable film grain effect to my game for artistic reasons. I am currently struggling to figure out the best way to do this. So far, I believe the right direction is using the post-processing example, but it would be nice to have more advice in regards to this.

[smoky elk]

If I were you - I might explore using a separate camera for something like this depending on your implementation

often times it's helpful to have a "clean" camera that your effect cameras can use - then you can set the order of the effect cameras higher depending on what effect you want to achieve

[scarlet shuttle]

using a separate camera for this would be overkill in my opinion. Film grain is just a post processing effect and using the post processing features should be more than enough for this