Add LoD hysteresis

[MatthewsSam]

Hi, after posting on the forum people suggested me to post here.

Here is my suggestion for an implementation of the first part in Godot Engine (I will do another ticket for the smooth transition)

1. Add an hysteresis, which means when you trigger a LoD change, to trigger it back to it's previous state you must go to a bigger distance
   For instance if we have a sphere that appears at 10 unit, to make it disappears, the player must go at ~13 units. This reduce the number of unwanted change.
   That could be done automatically with a fixed constant directly in the engine (something like 5 or 3) or with an option in the global project setting. Putting this on a per node basis would be IMHO a vast of time and potentially confusing (if offsets aren't the same across all mesh of the same object it can cause problems).

In the global editor setting there would be simply an option LoD Hysteresis: and by default it would be at 0 (= no effect).

If devs are interested I can try to submit a patch :)

Sam

[reduz]

ah nice, lets take note of this for 3.0

On Fri, Sep 2, 2016 at 2:28 PM, samuncle [email protected] wrote:

Hi, after posting on the forum
https://godotdevelopers.org/forum/discussion/comment/17817 people
suggested me to post here.

Here is my suggestion for an implementation of the first part in Godot
Engine (I will do another ticket for the smooth transition)

1. Add an hysteresis, which means when you trigger a LoD change, to
   trigger it back to it's previous state you must go to a bigger distance
   For instance if we have a sphere that appears at 10 unit, to make it
   disappears, the player must go at ~13 units. This reduce the number of
   unwanted change.
   That could be done automatically with a fixed constant directly in the
   engine (something like 5 or 3) or with an option in the global project
   setting. Putting this on a per node basis would be IMHO a vast of time and
   potentially confusing (if offsets aren't the same across all mesh of the
   same object it can cause problems).

In the global editor setting there would be simply an option LoD
Hysteresis: and by default it would be at 0 (= no effect).

If devs are interested I can try to submit a patch :)

Sam

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[Zylann]

Does Godot handle LoD at all currently?

[SuperUserNameMan]

@Zylann : through GeometryInstance.set_draw_range_begin/end()

[Zylann]

Oh. That means you need to create a MeshInstance for every LoD of a mesh for example?

I am still wondering how a chunked terrain node would perform with this, as the LoD in use depends on the LoD of neighbor chunks to avoid seams (but maybe it's a different issue).

Also, please consider multi-camera (split-screen, mirrors...) and VR when implementing LoD with hysteresis, as it may require to render different LoDs.

[nunodonato]

I see the hysteresis properties in the current master. Is it safe to close this?

[reduz]

this feature is a ton more difficult to implement than I initially thought, specially if your scene is being rendered by multiple cameras. if you can think of an algorithm to get it to work in that situation, let me know

[reduz]

will kick to 3.1 for now, will properly implement all the lod systems there

[Zireael07]

So why have the hysteresis property displayed in editor if it's not used?

[reduz]

@Zireael07 because the API is exposed, but the implementation is not written. Might be a good idea to hide it for the time being. Also it might probably be implemented different at some point

[volzhs]

@reduz probably should hide Hysteresis before RC1?
also, just LOD doesn't work I think either for now.

[ghost]

Still reproducible/relevant in 3.1 master 9ad1800 : VSScene::instance_geometry_set_draw_range does nothing. (Apparently it's planned for 3.1 but I think it's crucial to put in the docs that it's not yet implemented)

[akien-mga]

Moving to the next milestone as 3.1 is now feature frozen.

[MysteryGM]

Hi. The LOD system in Godot doesn't work at all, unless I am maybe doing something wrong?
I considered making the LOD system myself, that way I can also batch lower LODs etc, maybe I will do Hysteresis but I am not too good with shaders.

So what I am wondering is how far is the developers with the LOD system?
If I make the LOD system using GDscript will the Godot engine developers be able to integrate it into the engine?

Is GDscript slower than integration? Because if it isn't I could always make it as an addon.

[akien-mga]

Superseded by godotengine/godot-proposals#692.

[Norrox]

Is this an issue again? It's visible in the editor

[AThousandShips]

Please open a new issue and provide the details as well as a reproduction project

[Calinou]

This is already implemented in 4.x: https://docs.godotengine.org/en/latest/tutorials/3d/visibility_ranges.html (Ctrl + F for hysteresis)

For 3.x, see #53778.