UE4 4.5.1 & 4.6.0 integrations with 0.4.4 SDK are published

Can confirm, the 4.6 tag on the releases page does not include the VR preview feature.. off to compile the latest revision...

Try to get the latest from the github (Oculus-VR/4.6 branch) and re-build it (do not forget to install Oculus binary prerequisite package). Try to switch between Extend and Direct modes. Make sure the 0.4.4 Runtime is installed. If you've made modifications in the Engine as well - try to build unmodified Oculus version and test it first (meaning, just get whatever is in the Oculus-VR github branch and build it; do not apply your changes).
If nothing helps: try standalone game, does it work in stereo? Report here.

Heavy demo results (SpeedStep disabled):

Extended mode, UE 4.6 (official repo), ORv.0.4.3 : ~60fps
Direct mode: UE 4.6 (official repo), ORv.0.4.3 : 37.5fps

Extended Mode, UE 4.6 (official repo), ORv.0.4.4 : ~65-70fps
Direct mode: UE 4.6 (official repo), ORv.0.4.4 : 37.5fps

My heavy demo was running 75fps locked in Direct Mode on UE 4.3.1 using ORv0.4.1. No content changes since then.

Edit: Ran my older version of heavy demo (content practically identical, actually I had two Radiant UI webbrowser components in the scene running YouTube videos in addition):

Extended Mode, UE 4.3.1 (official repo), ORv.0.4.4 : ~70-75fps

This is the problem - your game can't make 75 fps. The only way Direct mode can work at full speed is to make your game to render at stable 75 fps through whole game. Direct mode requires harder sync between GPU/CPU and if the game can't make 75 fps then it switches to half frame (37.5) to avoid tearing. In any case, VR experience from any frame rate in between 37 and 75 won't be good.

"artyom17" wrote:
This is the problem - your game can't make 75 fps. The only way Direct mode can work at full speed is to make your game to render at stable 75 fps through whole game. Direct mode requires harder sync between GPU/CPU and if the game can't make 75 fps then it switches to half frame (37.5) to avoid tearing. In any case, VR experience from any frame rate in between 37 and 75 won't be good.

Hi Artyom17,

Do you foresee this changing in the future? If a frame takes 16.666 MS to generate as opposed to 13.333 MS, couldn't time warp be used to fill the gap with the previous frame+transform? I understand that this is not the primary purpose of time warp; but isn't it a side benefit? Isn't 3.333 MS a small enough time period for time warp to be effective here?

Thanks!

"andrewtek" wrote:

"artyom17" wrote:
This is the problem - your game can't make 75 fps. The only way Direct mode can work at full speed is to make your game to render at stable 75 fps through whole game. Direct mode requires harder sync between GPU/CPU and if the game can't make 75 fps then it switches to half frame (37.5) to avoid tearing. In any case, VR experience from any frame rate in between 37 and 75 won't be good.

Hi Artyom17,

Do you foresee this changing in the future? If a frame takes 16.666 MS to generate as opposed to 13.333 MS, couldn't time warp be used to fill the gap with the previous frame+transform? I understand that this is not the primary purpose of time warp; but isn't it a side benefit? Isn't 3.333 MS a small enough time period for time warp to be effective here?

Thanks!

We are investigating ways of implementing so called 'asynchronous timewarp' that would do pretty much that. But it is still in prototyping stage at the moment.

"artyom17" wrote:
Direct mode requires harder sync between GPU/CPU and if the game can't make 75 fps then it switches to half frame (37.5) to avoid tearing. In any case, VR experience from any frame rate in between 37 and 75 won't be good.

I understand this, but is it normal that since the introduction of the 0.4.3 runtime it switches to 37.5 when the game can't make 83 fps (not 75 fps)??

I reported this a while ago in this UE4 answerhub, and it has been confirmed by other users like Wollan:
https://answers.unrealengine.com/questions/124299/451-capped-at-375-fps.html

"PatimPatam" wrote:
I understand this, but is it normal that since the introduction of the 0.4.3 runtime it switches to 37.5 when the game can't make 83 fps (not 75 fps)??

artyom17 already said that Direct mode steals about 10% of performance compared to extended mode and that they were working on improving that.

75 FPS is 9.64% less than 83 FPS. With double-buffering and vsync you drop each other frame when you can't keep up, hence 37.5 FPS.

"Fredz" wrote:

"PatimPatam" wrote:
I understand this, but is it normal that since the introduction of the 0.4.3 runtime it switches to 37.5 when the game can't make 83 fps (not 75 fps)??

artyom17 already said that Direct mode steals about 10% of performance compared to extended mode and that they were working on improving that.

75 FPS is 9.64% less than 83 FPS. With double-buffering and vsync you drop each other frame when you can't keep up, hence 37.5 FPS.

I would understand if for example i had 82 FPS in Extended Mode and because of the 10% hit i get 74 FPS in Direct Mode, so it switches 37.5.

But the 83 FPS i'm saying are in Direct Mode after already taking a FPS hit in comparison to Extended Mode (or Direct Mode pre-0.4.3).

So in total it's almost like a 20% hit really (around 13 fps).

Location 1:

0.4.2 Direct Mode - 76 fps -> capped at 75 with vsync OK
0.4.3 Direct Mode - 71 fps -> capped at 37 with vsync NOK, but i understand

Location 2:

0.4.2 Direct Mode - 87 fps -> capped at 75 with vsync OK
0.4.3 Direct Mode - 82 fps -> capped at 37 with vsync !??

"PatimPatam" wrote:
0.4.2 Direct Mode - 87 fps -> capped at 75 with vsync OK
0.4.3 Direct Mode - 82 fps -> capped at 37 with vsync !??

So you mean that you take two hits by switching from Extended mode to Direct mode ? Ie. 10% less FPS then 10% more FPS required ? So basically 20% hit ? What is your FPS in extended mode to compare ?