Using Unity5.6(above) single-pass stereo rendering on Android (supported Multi-View) to render to a Texture2DArray (off-screen).
- Since Unity5.6 give us a new feature to support single-pass stereo rendering on Android platform through Multi-View (seems particularly for GearVR with Oculus SDK selected). Here is a simple example show you how Multi-View works and ScriptableRenderLoop really give me an insight about unity rendering loop. So I am trying to use this feature on our standalone VR headset, and this is the basic solution.
- Simply, this is a plugin you can used to let Unity Camera render to a Texture2DArray by 2 eyes. Then you can use this Texture2DArray to do whatever you want, for example, render them to a screen. It is very useful for VR, because you could save drawcalls (half of two cameras) and CPU overhead.
- This could only be used on an Android device with OpenGL 3 and GL_OVR_multiview extension supported.
- Unity5.6 and above, ensure the Virtual Reality Supported checkbox is ticked, then tick the Single-Pass Stereo Rendering checkbox underneath it.
- Using "Split Stereo Display (non head-mounted)" for sdks.
- Attach "RenderTexture2DArray" to the Camera you want to use and configure "Stereo Separation" to control two eyes distance.
- You can get the Texture2DArray through RenderTexture2DArray.renderTexture after its Awake.
- There is a simple demo I made in this repo, I used another Camera to render two Quad to screen to show the Texture2DArray's content.
- For someone may want to modify this plugin to integrate with their own project or just do some development with it, I would like to share these with you.
- Firstly, this Unity feature is a preview one, which means it's buggy and not stable.
- Secondly, this solution is a tricky way, I use native plugin to change Unity framebuffer to bind with my Texture2DArray and enable Unity's shader keywords "STEREO_MULTIVIEW_ON" to let it do the magic. So you may get wrong or nothing if you are not using the proper shader.
- Last, I calculate matrix for two eyes and set them for shaders in OnPreRender step, so if you want do magic about view projection matrix, you should probably do it here.
- The latest update [84b00bd] fixed skybox rendering, so far it seems to be OK.
- OnPostRender failed, according to offical documentation, post render in single pass stereo rendering mode should be treated very carefully and I find that the normal GL.LoadOrtho will not do the trick for us in this approach since it seems not awared that "we are in single pass mode", so I rewrite this method (RT2DARRAY.GL.LoadOrtho(Material)) and it works fine for me.