Fade in from black

http://www.unifycommunity.com/wiki/index.php?title=Fade

General purpose fading routines; I use that in most of my projects.

Here's the updated link

http://wiki.unity3d.com/index.php/Fade

And if you're trying to fade in from OVR 4.4 checkout OVR/Scripts/Util/OVRScreenFade.cs. Here I've modded it to control "manually".

 using UnityEngine;
 
 public class OVRScreenFadeCustom : MonoBehaviour
 {
     public float alpha = 1f;
     
     private Shader fadeShader = null;
     private Material fadeMaterial = null;
 
     void Awake()
     {
         fadeMaterial = (fadeShader != null) ? new Material(fadeShader) : new Material(Shader.Find("Transparent/Diffuse"));
     }
     
     void OnDestroy()
     {
         if (fadeMaterial != null)
         {
             Destroy(fadeMaterial);
         }
     }
 
     void OnPostRender()
     {
         if (alpha != 0)
         {
             fadeMaterial.color = new Color(0f, 0f, 0f, alpha);
 
             fadeMaterial.SetPass(0);
             GL.PushMatrix();
             GL.LoadOrtho();
             GL.Color(fadeMaterial.color);
             GL.Begin(GL.QUADS);
             GL.Vertex3(0f, 0f, -12f);
             GL.Vertex3(0f, 1f, -12f);
             GL.Vertex3(1f, 1f, -12f);
             GL.Vertex3(1f, 0f, -12f);
             GL.End();
             GL.PopMatrix();
         }
     }
 }

Add:

     public void FadeIn()
     {
         StartCoroutine(Fade(1, 0));
     }

to the code below:

 Copyright   :   Copyright (c) Facebook Technologies, LLC and its affiliates. All rights reserved.
 
 Licensed under the Oculus SDK License Version 3.4.1 (the "License");
 you may not use the Oculus SDK except in compliance with the License,
 which is provided at the time of installation or download, or which
 otherwise accompanies this software in either electronic or hard copy form.
 
 You may obtain a copy of the License at
 
 https://developer.oculus.com/licenses/sdk-3.4.1
 
 Unless required by applicable law or agreed to in writing, the Oculus SDK
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 
 ************************************************************************************/
 
 using UnityEngine;
 using System.Collections; // required for Coroutines
 
 /// <summary>
 /// Fades the screen from black after a new scene is loaded. Fade can also be controlled mid-scene using SetUIFade and SetFadeLevel
 /// </summary>
 public class OVRScreenFade : MonoBehaviour
 {
     [Tooltip("Fade duration")]
     public float fadeTime = 2.0f;
 
     [Tooltip("Screen color at maximum fade")]
     public Color fadeColor = new Color(0.01f, 0.01f, 0.01f, 1.0f);
 
     public bool fadeOnStart = true;
 
     /// <summary>
     /// The render queue used by the fade mesh. Reduce this if you need to render on top of it.
     /// </summary>
     public int renderQueue = 5000;
 
     private float uiFadeAlpha = 0;
 
     private MeshRenderer fadeRenderer;
     private MeshFilter fadeMesh;
     private Material fadeMaterial = null;
     private bool isFading = false;
 
     public float currentAlpha { get; private set; }
 
     void Awake()
     {
         // create the fade material
         fadeMaterial = new Material(Shader.Find("Oculus/Unlit Transparent Color"));
         fadeMesh = gameObject.AddComponent<MeshFilter>();
         fadeRenderer = gameObject.AddComponent<MeshRenderer>();
 
         var mesh = new Mesh();
         fadeMesh.mesh = mesh;
 
         Vector3[] vertices = new Vector3[4];
 
         float width = 2f;
         float height = 2f;
         float depth = 1f;
 
         vertices[0] = new Vector3(-width, -height, depth);
         vertices[1] = new Vector3(width, -height, depth);
         vertices[2] = new Vector3(-width, height, depth);
         vertices[3] = new Vector3(width, height, depth);
 
         mesh.vertices = vertices;
 
         int[] tri = new int[6];
 
         tri[0] = 0;
         tri[1] = 2;
         tri[2] = 1;
 
         tri[3] = 2;
         tri[4] = 3;
         tri[5] = 1;
 
         mesh.triangles = tri;
 
         Vector3[] normals = new Vector3[4];
 
         normals[0] = -Vector3.forward;
         normals[1] = -Vector3.forward;
         normals[2] = -Vector3.forward;
         normals[3] = -Vector3.forward;
 
         mesh.normals = normals;
 
         Vector2[] uv = new Vector2[4];
 
         uv[0] = new Vector2(0, 0);
         uv[1] = new Vector2(1, 0);
         uv[2] = new Vector2(0, 1);
         uv[3] = new Vector2(1, 1);
 
         mesh.uv = uv;
 
         SetFadeLevel(0);
     }
 
     /// <summary>
     /// Start a fade out
     /// </summary>
     public void FadeOut()
     {
         StartCoroutine(Fade(0,1));
     }
 
 
     /// <summary>
     /// Starts a fade in when a new level is loaded
     /// </summary>
     void OnLevelFinishedLoading(int level)
     {
         StartCoroutine(Fade(1,0));
     }
 
     /// <summary>
     /// Automatically starts a fade in
     /// </summary>
     void Start()
     {
         if (fadeOnStart)
         {
             StartCoroutine(Fade(1,0));
         }
     }
 
     void OnEnable()
     {
         if (!fadeOnStart)
         {
             SetFadeLevel(0);
         }
     }
 
     /// <summary>
     /// Cleans up the fade material
     /// </summary>
     void OnDestroy()
     {
         if (fadeRenderer != null)
             Destroy(fadeRenderer);
         
         if (fadeMaterial != null)
             Destroy(fadeMaterial);
         
         if (fadeMesh != null)
             Destroy(fadeMesh);
     }
 
     /// <summary>
     /// Set the UI fade level - fade due to UI in foreground
     /// </summary>
     public void SetUIFade(float level)
     {
         uiFadeAlpha = Mathf.Clamp01(level);
         SetMaterialAlpha();
     }
     /// <summary>
     /// Override current fade level
     /// </summary>
     /// <param name="level"></param>
     public void SetFadeLevel(float level)
     {
         currentAlpha = level;
         SetMaterialAlpha();
     }
 
     /// <summary>
     /// Fades alpha from 1.0 to 0.0
     /// </summary>
     IEnumerator Fade(float startAlpha, float endAlpha)
     {
         float elapsedTime = 0.0f;
         while (elapsedTime < fadeTime)
         {
             elapsedTime += Time.deltaTime;
             currentAlpha = Mathf.Lerp(startAlpha, endAlpha, Mathf.Clamp01(elapsedTime / fadeTime));
             SetMaterialAlpha();
             yield return new WaitForEndOfFrame();
         }
     }
 
     /// <summary>
     /// Update material alpha. UI fade and the current fade due to fade in/out animations (or explicit control)
     /// both affect the fade. (The max is taken) 
     /// </summary>
     private void SetMaterialAlpha()
     {
         Color color = fadeColor;
         color.a = Mathf.Max(currentAlpha, uiFadeAlpha);
         isFading = color.a > 0;
         if (fadeMaterial != null)
         {
             fadeMaterial.color = color;
             fadeMaterial.renderQueue = renderQueue;
             fadeRenderer.material = fadeMaterial;
             fadeRenderer.enabled = isFading;
         }
     }
 }