Turn off culling

[SpiderPig]

Can I turn off culling for a particular camera?

[Josh]

Which engine?

[SpiderPig]

Ah, Ultra Engine.

[Josh]

Ultra only uses frustum culling. People seem to have very little tolerance for the artifacts that GPU occlusion culling involves, so in the future I am more likely to look into some type of BSP system.

Why would you want to render everything in the world that is out of the camera's view?

[SpiderPig]

Oh I just have some simple meshes rendering to the UI camera, and I move them about, in and out of view for reasons too complex to explain.  I've mentioned before that especially in debug mode the culling is quite slow at the moment.  I thought If I could turn off culling for the UI camera it would probably solve the small issue, that's all.

[Josh]

Is there a problem when release mode is run?

[SpiderPig]

Haven't tested that in a while due to the version mismatch thing but I remember it being a lot better in Release, but still noticeable.

[SpiderPig]

I just figured that if the UI follows the camera then turning culling off would nip the issue it in the bud.

[reepblue]

4 hours ago, Josh said:

Ultra only uses frustum culling. People seem to have very little tolerance for the artifacts that GPU occlusion culling involves, so in the future I am more likely to look into some type of BSP system.

Thank you for reading the feedback I got with Cyclone. People never shut up about this. 

[Dreikblack]

btw is that culling effect when brushes partly disappear behind another one? But should not be due transparency of the brush in this case.

For clarification blue outlines and yellow tetrahedron are brushes. Yellow lines are models. This happens with some camera positions and with another ones all looks fine.

[Josh]

Disable transparency on the material used for the yellow wireframe.

[Dreikblack]

If you mean tetrahedron i need it to be transparent with ~25% alpha. Other brushes are not transparent. btw i'm using unlit material, idk if there is a better ways to achieve this visual result (except bug part).

3 lines are not wireframe but 3 models.

[Josh]

Is the material for the yellow arrow using transparency?

[Josh]

This is what a tetrahedron is:

[Dreikblack]

2 hours ago, Josh said:

Is the material for the yellow arrow using transparency

No. It's not an arrow tho but 3 not transparent lines from 1 point to 3 characters.

 

2 hours ago, Josh said:

This is what a tetrahedron is:

Yep. Probably had to do screen from another angle from bigger distance but pale yellow transparent shape is tetrahedron with sharp angle behind bottom left corner.

I can make an example later for an issue reproducing.

[Josh]

4 minutes ago, Dreikblack said:

Yep. Probably had to do screen from another angle from bigger distance but pale yellow transparent shape is tetrahedron with sharp angle behind bottom left corner.

Oh okay, I thought you meant the blue squares. 

Okay, ordering and transparency is difficult for GPUs to get right. Blending can only occur on top of what has already been rendered, so the renderer orders objects from furthest to closest. If the objects overlap then you can get situations where one doesn't appear underneath another. This is a general problem that all real-time renderers have.

You might get different results by enabling refraction on the camera, but this will probably always be a problem if you have overlapping transparent objects.

[Dreikblack]

Only yellow tetrahedron is transparent object in scene tho. Blue squares and yellow lines are not transparent, they just has a unlit shader ans that's it.

 

[Josh]

Are they all using the same renderlayer / camera?

[Dreikblack]

Yes. I think only character second model for outlines uses another renderlayer and they looks fine (or i did not yet found angle for them to see an issues)

[Josh]

If you can produce a simple example please upload it and I'll take a look.

[SpiderPig]

Soooo back to my original question.  Is possible to turn off frustum culling?

[Josh]

Not at this time, but...

I ran into something similar with the GUI system. When things slid into view, they would appear suddenly. My solution was to always draw these objects when they are not hidden, regardless of whether they are in view or not.

When it comes to a scene with a hierarchy it gets more complicated. If there was a per-entity "always draw" flag it would need to travel up the entire octree structure. I do this with some special types like lights, but it is very sensitive and errors are difficult to detect, so I am cautious to add something new there.

Another option might be a fixed visibility list, where you explicitly specify a list of entities a camera draws, and it skips the entire culling process. This might be appropriate for things that are very close to the camera, like 3D interface elements and FPS weapons.

Another option might be to add a padding value that artificially enlarges the camera frustum.

Yet another approach is to expand the visibility bounding box of entities based on velocity!

There are many ways to go about this. I prefer to let people use the system first so we can get a better understanding of what the best solution is, before I implement one of the above or something else.

[SpiderPig]

Yeah that's a good approach.  Personally I like the idea of selecting which entities should have fixed visibily, especially for UI.  But enlarging the frustrum may have uses too.

[Dreikblack]

On 6/23/2023 at 3:07 PM, Josh said:

If you can produce a simple example please upload it and I'll take a look.

You was right about SetTransparent. After all i found out i was keeping same unlit mat so accidentally applied transparency to every model/brush with it (alpha channel was 1 tho for objects that non intended to be transparent)