Camera Depth Texture from a second camera with replacement shader

Question

I'm trying to access another camera's depth texture inside a shader.

The setup is like this:

The main camera has no script attached that renders to depth buffer or something. It's a simple camera. The second camera has a replacement shader, replaced by a script "ReplaceAndUseDepth.cs", that renders only some objects from the scene (those who have a shader tagged with "Focused").

The problem that I can't solve:

I want this replacement shader to make use of the second camera's depth buffer. But accessing it with uniform sampler2D _CameraDepthTexture will not get me anything.

Answer 1

Best Answer

Answer by Razziel · Feb 20, 2018 at 09:58 PM

I managed to solve this. My second's camera target texture was set to something different than null. That seemed to cause the problem. Also, I used custom target buffers to make sure that I get the second's camera depth buffer, using :

 target = new RenderTexture(mainCamera.pixelWidth, mainCamera.pixelHeight, 16, RenderTextureFormat.Default);
         targetDepth = new RenderTexture(mainCamera.pixelWidth, mainCamera.pixelHeight, 24, RenderTextureFormat.Depth);
 
         secondCamera.SetTargetBuffers(target.colorBuffer, targetDepth.depthBuffer);
 
         //secondCamera.targetTexture = target; **COMMENTED LINE**
 
         Shader.SetGlobalTexture(targetColorName, target);
         Shader.SetGlobalTexture(targetDepthName, targetDepth);

With this code, using the uniform sampler2D [targetDepthName]will get me exactly what _CameraDepthTexture would normally get me if I had a simple setup with only one camera.

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Answer 2

Answer by klemen_unity · Mar 01, 2018 at 05:08 PM

Hey @Razziel, I'm trying to do the same thing, use a secondary camera's depth in a shader. _LastCameraDepthTexture always looks the same as _CameraDepthTexture for me. Are you able to share a more detailed breakdown of your solution?

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Razziel · Mar 05, 2018 at 04:30 PM 1

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Hey @klemen_unity, I'm going to show you a script attached to the secondary camera:

 [ExecuteInEditMode]
 public class ReplaceCameraShader : MonoBehaviour {
     public Camera mainCamera; // main camera
     private Camera cameraComp; // second camera
     public Shader replacedWith;
     public static readonly string targetTextureName = "_TransparencyFocusMask";
     public static readonly string targetDepthName = "_DepthFocusMask";
 
     private RenderTexture target;
     private RenderTexture targetDepth;
 
     private void OnEnable() {
         cameraComp = GetComponent<Camera>();
         cameraComp.depthTextureMode = DepthTextureMode.None;
 
         //cameraComp.SetReplacementShader(replacedWith, "Focused");
 
         target = new RenderTexture(mainCamera.pixelWidth, mainCamera.pixelHeight, 24, RenderTextureFormat.ARGBFloat);
         targetDepth = new RenderTexture(mainCamera.pixelWidth, mainCamera.pixelHeight, 24, RenderTextureFormat.Depth);
 
         Shader.SetGlobalTexture(targetTextureName, target);
         Shader.SetGlobalTexture(targetDepthName, targetDepth);
 
         cameraComp.SetTargetBuffers(target.colorBuffer, targetDepth.depthBuffer);
 
     }
 
     private void OnDisable() {
         cameraComp = GetComponent<Camera>();
         //cameraComp .ResetReplacementShader();
 
         if (cameraComp.targetTexture != null) {
             RenderTexture temp = cameraComp.targetTexture;
             cameraComp.targetTexture = null;
             DestroyImmediate(temp);
         }
         target = null;
         targetDepth = null;
         Shader.SetGlobalTexture(targetDepthName, targetDepth);
         Shader.SetGlobalTexture(targetTextureName, target);
     }
 }

With this script you can definitely use the secondary's camera depth texture AND color texture (what the camera sees). And you access them, in the shader with uniform sampler2D _DepthFocusMask. You can see that i commented the lines mentioning the shader replacement. That's because i ran in a different problem. (You can see it here: https://answers.unity.com/questions/1472358/problem-with-camera-target-texture-and-replacement.html ) But, as far as getting the secondary's camera depth texture, this method works.

Camera Depth Texture from a second camera with replacement shader

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