Add VR Single-Pass Instanced mode support to AVPro

[Shii2]

Right now video and Media Player UI only rendered in one eye in VR mode when using Single-Pass Instanced mode. Starting from Unity 2020.1 they removed regular Single Pass mode support and only left Multipass and Single-Pass Instanced modes so AVPro not usable when using SPI mode on new Unity versions. (And Multipass is a bad alternative since it much slower)

Is is possible to add SPI support to AVPro by default?

For now after every AVPro update I have to modify shaders manually to add SPI support to them. It's a simple edit, I have to add: UNITY_VERTEX_INPUT_INSTANCE_ID to appdata struct UNITY_VERTEX_OUTPUT_STEREO to v2f output struct and

    UNITY_SETUP_INSTANCE_ID(v);
    UNITY_INITIALIZE_OUTPUT(v2f, o);
    UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);

to v2f vert and #pragma multi_compile_instancing More info about SPI integration can be found here: https://docs.unity3d.com/Manual/SinglePassInstancing.html

[AndrewRH]

As far as I know we do support this in most of our shaders. The MediaPlayer demo scene just isn't assigned a shader that supports stereo by default. If you assign a stereo shader then it should work?

[Shii2]

I checked demo scene and creating custom material with one of AVProVideo Lit/Unlit/Transparent shaders then plugging in this material into VideoPlayerUI/Video/VideoDisplay/Display uGUI component indeed works for video but not for demo Media Player UI parts. For example for default demo scene AVPro selects AVProVideo/Internal/UI/Transparent Packed shader that does not support Single-Pass Instanced mode. Also some demo media player elements rendered only in left eye because Unlit/MediaPlayerUI also missing SPI support. Can this support be added to media player demo UI shader and internal shaders from Shaders/Resources folder too, so I won't need to manually create custom material with SPI supported shader each time?

[DaveXR]

Can you just support Single pass? We've got a complex app which uses 3D and video (including spherical video) and we need all the performance we can get for all this.