Is it possible for a global variable to contain a different value per camera?

I have a URP project that I've set up, and have created several shaders using the Shader Graph. Each of these shaders have a boolean in common that I toggle to change how things are rendered (e.g. heat vision). This allows me to have a bunch of different shaders (one for water, one for tri-planar, one for transparency, etc) and all I need to do to swap vision is a single SetGlobalFloat call.

This setup works flawlessly for a single camera setup. However, I would like to introduce the concept of split-screen to my game, where one side of the screen has one global float value (normal rendering), and the other side of the screen has a different global float value (heat vision). Is this possible?

If this is not possible, it sounds like I will need to separate my shaders into their respective float variants (normal shader and heat vision shader); however, that would make rendering with multiple shaders (tri-planar, water, etc.) much more complicated.

What would be a recommended workflow here?

 

You should be able to change the global shader value during https://docs.unity3d.com/ScriptReference/Camera.OnPreRender.html
of the camera. So you could have a script on each camera which has properties for setting the render mode on that camera, and then the script will set that render mode during OnPreRender();

 

If you're using URP you can use beginCameraRendering event to change your globals.

 

Thank you both! Learning about

OnPreRender

got me on a trail towards

beginCameraRendering

, which has me on the right track. It looks like I just need to register a function once, instead of including its own

OnPreRender

script attached to my camera.

Following that trail has led me to ScriptableRenderContext.SetupCameraProperties, which I may or may not need if I can get the global floats working.

 

Got it working without needing SetupCameraProperties - thanks so much for pointing me in the right direction! This is the (simplified) script that I used in case anyone else runs into the same issue:

Code (CSharp):

1. using UnityEngine.Rendering;
2.  
3. public class ExampleSplitscreen : MonoBehaviour {
4.   int shaderToggle;
5.   void Start() {
6.     // Register the function to beginCameraRendering. Only register this once, regardless of how many cameras exist
7.     RenderPipelineManager.beginCameraRendering += HandleVision;
8.   }
9.   void HandleVision(ScriptableRenderContext context, Camera camera) {
10.     // Check for which camera it's running against, and handle logic accordingly
11.     if(camera == camera1) shaderToggle = 0;
12.     else shaderToggle = 1;
13.     Shader.SetGlobalFloat("vision", shaderToggle);

You'd then have an unexposed boolean in your shader that handles the rendering differences (only variables that aren't exposed can be manipulated using scripts).