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;
-        /// <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();
+        public PortalCamera portalCamera;
 
         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);
-            }
         }
     }
 }