refactor portal rendering into portal camera

Assets/Escape Room Engine/Portal/Portal.cs

@@ -1,108 +1,23 @@
 using System;
-using System.Collections.Generic;
 using UnityEngine;
-using UnityEngine.Rendering;
-using UnityEngine.Rendering.Universal;
-using UnityEngine.XR;
 
 namespace Escape_Room_Engine.Portal
 {
     public class Portal : MonoBehaviour
     {
-        private static readonly Matrix4x4 HalfRotation = Matrix4x4.Rotate(Quaternion.Euler(0, 180, 0));
-        private static readonly Camera.StereoscopicEye[] Eyes =
-            { Camera.StereoscopicEye.Left, Camera.StereoscopicEye.Right };
-        private static readonly Dictionary<Camera.StereoscopicEye, int> EyeTextureNames = new()
-            {
-                { Camera.StereoscopicEye.Left, Shader.PropertyToID("_LeftTex") },
-                { Camera.StereoscopicEye.Right, Shader.PropertyToID("_RightTex") }
-            };
-
         /// <summary>
         /// The portal that is connected with this one.
         /// </summary>
         public Portal other;
         /// <summary>
-        /// The minimum near clip plane distance to be used when calculating the oblique clip plane.
-        /// </summary>
-        public float minNearClipPlane = 0.02f;
-        /// <summary>
         /// The camera that will draw the view for this portal.
         /// </summary>
-        [SerializeField] private Camera portalCamera;
+        public PortalCamera portalCamera;
-        /// <summary>
-        /// The quad where the rendered texture will be drawn on.
-        /// </summary>
-        [SerializeField] private MeshRenderer portalQuad;
-
-        private PlayerCamera _playerCamera;
-        private Dictionary<Camera.StereoscopicEye, RenderTexture> _textures = new();
 
         private void Awake()
         {
             // check whether the other portal is set up
             if (!other || other.other != this) throw new Exception("Other portal not set up correctly.");
-            
-            // get player camera
-            if (Camera.main != null) _playerCamera = Camera.main.GetComponent<PlayerCamera>();
-            else throw new Exception("Main camera has no player camera script set up.");
-        }
-
-        private void OnEnable()
-        {
-            RenderPipelineManager.beginCameraRendering += Render;
-        }
-
-        private void OnDisable()
-        {
-            RenderPipelineManager.beginCameraRendering -= Render;
-        }
-
-        private void Render(ScriptableRenderContext scriptableRenderContext, Camera camera)
-        {
-            // check whether the portal plane is visible from the player camera
-            var frustumPlanes = GeometryUtility.CalculateFrustumPlanes(_playerCamera.camera);
-            if (!GeometryUtility.TestPlanesAABB(frustumPlanes, other.portalQuad.bounds))
-                // don't render this portal if it is not visible
-                return;
-            
-            var t = transform;
-
-            foreach (var eye in Eyes)
-            {
-                // create portal texture if it doesn't exist yet
-                if (!_textures.ContainsKey(eye))
-                {
-                    if (XRSettings.eyeTextureWidth > 0 && XRSettings.eyeTextureHeight > 0)
-                    {
-                        _textures.Add(eye,
-                            new RenderTexture(XRSettings.eyeTextureWidth, XRSettings.eyeTextureHeight, 24));
-                        other.portalQuad.material.SetTexture(EyeTextureNames[eye], _textures[eye]);
-                    }
-                    else // no texture was created so nothing should be rendered
-                        continue;
-                }
-                
-                // position portal camera
-                var m = t.localToWorldMatrix * HalfRotation * other.transform.worldToLocalMatrix *
-                        _playerCamera.getEyeTransform(eye).localToWorldMatrix;
-                portalCamera.transform.SetPositionAndRotation(m.GetPosition(), m.rotation);
-                portalCamera.projectionMatrix = _playerCamera.camera.GetStereoProjectionMatrix(eye);
-        
-                // set camera clip plane to portal (otherwise the wall behind the portal would be rendered)
-                // calculating the clip plane: https://computergraphics.stackexchange.com/a/1506
-                var n = -t.forward; // clip plane normal
-                var portalPlane = new Plane(n, t.position); // clip plane in world space
-                var clipPlane = portalCamera.worldToCameraMatrix.inverse.transpose *
-                                new Vector4(n.x, n.y, n.z, portalPlane.distance); // vector format clip plane in camera space
-                if (Math.Abs(portalPlane.GetDistanceToPoint(portalCamera.transform.position)) >= minNearClipPlane)
-                    // only adjust the near clip plane if it doesn't intersect with the camera
-                    portalCamera.projectionMatrix = portalCamera.CalculateObliqueMatrix(clipPlane);
-        
-                // render portal view
-                portalCamera.targetTexture = _textures[eye];
-                UniversalRenderPipeline.RenderSingleCamera(scriptableRenderContext, portalCamera);
-            }
         }
     }
 }

Assets/Escape Room Engine/Portal/Portal.prefab

@@ -48,8 +48,7 @@ MonoBehaviour:
   m_Name: 
   m_EditorClassIdentifier: 
   other: {fileID: 0}
-  portalCamera: {fileID: 7791795762741173939}
+  portalCamera: {fileID: 17691322601746172}
-  portalQuad: {fileID: 6216133567950691622}
 --- !u!1 &6911937082098131204
 GameObject:
   m_ObjectHideFlags: 0
@@ -144,6 +143,7 @@ GameObject:
   - component: {fileID: 2398425302420252226}
   - component: {fileID: 7791795762741173939}
   - component: {fileID: 5969531196797302096}
+  - component: {fileID: 17691322601746172}
   m_Layer: 0
   m_Name: Camera
   m_TagString: Untagged
@@ -242,6 +242,21 @@ MonoBehaviour:
   m_RequiresDepthTexture: 0
   m_RequiresColorTexture: 0
   m_Version: 2
+--- !u!114 &17691322601746172
+MonoBehaviour:
+  m_ObjectHideFlags: 0
+  m_CorrespondingSourceObject: {fileID: 0}
+  m_PrefabInstance: {fileID: 0}
+  m_PrefabAsset: {fileID: 0}
+  m_GameObject: {fileID: 7398326895463990628}
+  m_Enabled: 1
+  m_EditorHideFlags: 0
+  m_Script: {fileID: 11500000, guid: ad60e3973ab83f3468637a06970d7f1f, type: 3}
+  m_Name: 
+  m_EditorClassIdentifier: 
+  minNearClipPlane: 0.02
+  portal: {fileID: 1249363658}
+  portalQuad: {fileID: 6216133567950691622}
 --- !u!1001 &1842852527293547269
 PrefabInstance:
   m_ObjectHideFlags: 0

Assets/Escape Room Engine/Portal/PortalCamera.cs

@@ -0,0 +1,106 @@
+using System;
+using System.Collections.Generic;
+using UnityEngine;
+using UnityEngine.Rendering;
+using UnityEngine.Rendering.Universal;
+using UnityEngine.XR;
+
+namespace Escape_Room_Engine.Portal
+{
+    [RequireComponent(typeof(Camera))]
+    public class PortalCamera : MonoBehaviour
+    {
+        private static readonly Matrix4x4 HalfRotation = Matrix4x4.Rotate(Quaternion.Euler(0, 180, 0));
+        private static readonly Camera.StereoscopicEye[] Eyes =
+            { Camera.StereoscopicEye.Left, Camera.StereoscopicEye.Right };
+        private static readonly Dictionary<Camera.StereoscopicEye, int> EyeTextureNames = new()
+        {
+            { Camera.StereoscopicEye.Left, Shader.PropertyToID("_LeftTex") },
+            { Camera.StereoscopicEye.Right, Shader.PropertyToID("_RightTex") }
+        };
+
+        /// <summary>
+        /// The minimum near clip plane distance to be used when calculating the oblique clip plane.
+        /// </summary>
+        public float minNearClipPlane = 0.02f;
+        /// <summary>
+        /// The portal this camera renders through.
+        /// </summary>
+        [SerializeField] private Portal portal;
+        /// <summary>
+        /// The quad where the rendered texture will be drawn on.
+        /// </summary>
+        [SerializeField] private MeshRenderer portalQuad;
+
+        private PlayerCamera _playerCamera;
+        private Camera _camera;
+        private readonly Dictionary<Camera.StereoscopicEye, RenderTexture> _textures = new();
+
+        private void Awake()
+        {
+            // get player camera
+            if (Camera.main != null) _playerCamera = Camera.main.GetComponent<PlayerCamera>();
+            else throw new Exception("Main camera has no player camera script set up.");
+            
+            // get portal camera
+            _camera = GetComponent<Camera>();
+        }
+
+        private void OnEnable()
+        {
+            RenderPipelineManager.beginCameraRendering += Render;
+        }
+
+        private void OnDisable()
+        {
+            RenderPipelineManager.beginCameraRendering -= Render;
+        }
+        
+        private void Render(ScriptableRenderContext scriptableRenderContext, Camera camera)
+        {
+            // check whether the portal plane is visible from the player camera
+            var frustumPlanes = GeometryUtility.CalculateFrustumPlanes(_playerCamera.camera);
+            if (!GeometryUtility.TestPlanesAABB(frustumPlanes, portal.other.portalCamera.portalQuad.bounds))
+                // don't render this portal if it is not visible
+                return;
+            
+            var t = portal.transform;
+
+            foreach (var eye in Eyes)
+            {
+                // create portal texture if it doesn't exist yet
+                if (!_textures.ContainsKey(eye))
+                {
+                    if (XRSettings.eyeTextureWidth > 0 && XRSettings.eyeTextureHeight > 0)
+                    {
+                        _textures.Add(eye,
+                            new RenderTexture(XRSettings.eyeTextureWidth, XRSettings.eyeTextureHeight, 24));
+                        portal.other.portalCamera.portalQuad.material.SetTexture(EyeTextureNames[eye], _textures[eye]);
+                    }
+                    else // no texture was created so nothing should be rendered
+                        continue;
+                }
+                
+                // position portal camera
+                var m = t.localToWorldMatrix * HalfRotation * portal.other.transform.worldToLocalMatrix *
+                        _playerCamera.getEyeTransform(eye).localToWorldMatrix;
+                transform.SetPositionAndRotation(m.GetPosition(), m.rotation);
+                _camera.projectionMatrix = _playerCamera.camera.GetStereoProjectionMatrix(eye);
+        
+                // set camera clip plane to portal (otherwise the wall behind the portal would be rendered)
+                // calculating the clip plane: https://computergraphics.stackexchange.com/a/1506
+                var n = -t.forward; // clip plane normal
+                var portalPlane = new Plane(n, t.position); // clip plane in world space
+                var clipPlane = _camera.worldToCameraMatrix.inverse.transpose *
+                                new Vector4(n.x, n.y, n.z, portalPlane.distance); // vector format clip plane in camera space
+                if (Math.Abs(portalPlane.GetDistanceToPoint(transform.position)) >= minNearClipPlane)
+                    // only adjust the near clip plane if it doesn't intersect with the camera
+                    _camera.projectionMatrix = _camera.CalculateObliqueMatrix(clipPlane);
+        
+                // render portal view
+                _camera.targetTexture = _textures[eye];
+                UniversalRenderPipeline.RenderSingleCamera(scriptableRenderContext, _camera);
+            }
+        }
+    }
+}

Assets/Escape Room Engine/Portal/PortalCamera.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: ad60e3973ab83f3468637a06970d7f1f
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: