HDRP: How to trigger shadow map calculation via script?

Hi,

currently i have real time shadow map calculation activated, but i only need the "updating" in a really specific time frame so i would like to trigger it myself (choosing "On Demand" in settings).

But i cannot find how i can trigger it.

Can you help me?

 

https://forum.unity.com/threads/requestshadowmaprendering-is-internal.764924/

 

Thanks this helped @alexandre-fiset

But there is something off. If i enable the realtime shadows everything looks as expected and the shadows look like they should.

But if i stop doing this and choosing the ondemand version, the shadows only look good when i trigger the shadow generation "manually" each frame. The moment i stop triggering it, it starts to look bad and "random blobs of shadow" appear on the ground. I also noticed that all other shadows are disappearing.

Is this triggering only happening for this single frame? If yes, is there a way to "remember" the latest shadow map somehow?


Here a picture how it looks like WITHOUT triggering the shadow map generation each frame
https://imgur.com/a/titI1i5

 

Not sure if you've figured this out already, but apparently OnDemand shadow maps are generated according to the camera frustum at the time of the request. At least this is the behavior I've noticed while changing the camera view and calling the HDAdditionalLightData.RequestShadowMapRendering() function.

There is a thread out there where this is sort of documented, but I can't seem to find it just yet.

 

In Unity 2020.3.34 this problem persists...

Any idea?

 

Well to me it works fine.

I use HDAdditionalLightData.RequestShadowMapRendering() a few frames after loading a scene, then for some lights I update them each frame when moving an object or by passing under.

You need a Cache Atlas big enough to fit the cached shadows. In 2020.3.34, shadow caching is for punctual and area lights. The directionnal itself works with OnDemand but per its non-cached shadows nature you might need to update it more frequently.

 

I tried to set Cached Shadow Atlas Resolution to 16384, but the problem persists...

 

Problem solved!

It is not possible to update shadows and reflection probes during the same frame properly.
So I have to update shadows, wait for one frame, and then update reflection probes.