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- Dec 30, 2023
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Just checked the VAM2 alpha2 and it didn't have Single Pass VR Rendering enabled. I guess because it breaks all non-unity shaders and you get a grey screen on one eye and a black screen on the right eye for every shader used. What it does:
In VR every frame needs to be rendered twice from two angles. If you use Multi Pass (currently enabled in VAM2a2), left and right eye are rendered after another. If you use Single Pass (currently enabled in vam1) both eyes are rendered at the same time. If you use Single Pass Instanced, both eyes are rendered at the same time and all entities are rendered with a single draw call instead of two, hence the name "instanced". In a scene in VR with many entities this halves the amount of draw calls, speeding up the CPU part and improving GPU performance a bit while rendering, the GPU gets less bottlenecked by the CPU in the frame rendering.
How to enable it: https://docs.unity3d.com/2022.3/Documentation/Manual/SinglePassStereoRendering.html
However this breaks all non-unity-bundled shaders and you need to add 5 lines to every shader file: https://docs.unity3d.com/2022.3/Documentation/Manual/SinglePassInstancing.html
Depending on the CPU, FPS goes up from 70 to 90 in VR.
@meshedvr I hope you have that on the radar for vam2, the work needed is minimal, you just need to add 5 lines into every shader (not compute shaders) you made yourself or got from the unity store. In return you get a noticeable FPS boost in VR.
In VR every frame needs to be rendered twice from two angles. If you use Multi Pass (currently enabled in VAM2a2), left and right eye are rendered after another. If you use Single Pass (currently enabled in vam1) both eyes are rendered at the same time. If you use Single Pass Instanced, both eyes are rendered at the same time and all entities are rendered with a single draw call instead of two, hence the name "instanced". In a scene in VR with many entities this halves the amount of draw calls, speeding up the CPU part and improving GPU performance a bit while rendering, the GPU gets less bottlenecked by the CPU in the frame rendering.
How to enable it: https://docs.unity3d.com/2022.3/Documentation/Manual/SinglePassStereoRendering.html
However this breaks all non-unity-bundled shaders and you need to add 5 lines to every shader file: https://docs.unity3d.com/2022.3/Documentation/Manual/SinglePassInstancing.html
Depending on the CPU, FPS goes up from 70 to 90 in VR.
@meshedvr I hope you have that on the radar for vam2, the work needed is minimal, you just need to add 5 lines into every shader (not compute shaders) you made yourself or got from the unity store. In return you get a noticeable FPS boost in VR.
