Hello everyone, I wanted to share with you how I did a CRT effect on in game screens using only post process!

For context, I've been working on this project solo for the past 6 months and I started learning coding 8 months ago. So please take all of this as a very DIY method. I am not in any way recommending to use this as I'm sure a lot of seasoned programmers will cringe really hard and tell me that's a stupid way of doing it :p

To me, shaders are really hard to understand... I've tried so many times to follow a tutorial just to give up a few minutes in because I don't understand what they are doing and I hate just copy pasting a tutorial...

My problem:  
I needed to have a CRT effect applied on screens in game, meaning that the effect needs to be applied only on a small part of the game viewport, not on everything!

So I looked online for tutorials to do a CRT effect, and found a LOT of them. But ALL of the ones I found would apply the effect on the whole screen.  
My game screen has 3 "CRT" screens, so it doesn't work... But I did learn how to make the effect using post process, that a first step.  
Then I thought I could have a camera that only renders the "screens" layer and only apply the post process on that camera! But nope, it doesn't work... 

turns out, if you do this, the post process will "bleed" to the layers underneath and is applied to the rest of the game, even on cameras without post process.

Researching about this issue I found this video: [https://www.youtube.com/watch?v=7\_Vy0jDqjvM](https://www.youtube.com/watch?v=7_Vy0jDqjvM) and this unity forum thread: [https://discussions.unity.com/t/post-processing-with-multiple-cameras-is-currently-very-problematic/822011/268](https://discussions.unity.com/t/post-processing-with-multiple-cameras-is-currently-very-problematic/822011/268)

Bummer I thought, looks like it's kinda complicated to work around...  
But in the forum thread I read something interesting, that they fixed a "bug" with the render textures not having an alpha output.  
  
So I looked into this render texture thing and turned out that was my solution!!  
  
Use a camera to "film" the UI of my screen, apply post process on this camera, then output this camera on a renderTexture, and put this texture "in" my screen!

It works!

So now I have 3 cameras filming the screens texures, and I apply a different post process on each of these cameras. The result is exactly what I wanted! No shaders, just post process!

For the glitch effect, I did use a "post process" effect from : [https://github.com/saimarei/URPGlitch](https://github.com/saimarei/URPGlitch)  
It does use shaders here in the background, but I can apply the effect directly from the volume as a post process effect, so still a win for me!

TLDR: I used Cameras with output on render textures and applied post process on those cameras.

How I achieved a CRT effect + Vfx on ingame screens with Post Process