Any chance you will be adding decals.

[arconovum]

As the title , any chance you will add decals in the 'primary' render mode? , not alternate or experimental render modes.

[alipbcs]

I'm open to support decals, but haven't had much experience with them. Are they similar to what's described here, where the goal is to apply additional textures on top of existing ones?

[arconovum]

The text you refer to only explains the developer aspect of decals , but does not address the graphics art pipeline, which is far more time consuming than the prior. Any time savings is always welcomed when creating graphics, which need to remain fluid, and flexible to allow quick changes. Decals allow this easy increase in detail, and also allows for easy simple and flexible design changes.

An embedded decal vs. decals as a separate dynamic texture would be very cumbersome, this would only limit the positioning in scenarios such as along inter mesh seams, would not be economically viable long term, ultimately stifling creativity.

The dynamic nature of decals is also worth making note of, this allows for real time splatting of decals, that can be layered , with little to no significant texture overhead cost.

Even if I don't formulate a convincing argument for the need of decals, Decals have already proven themselves worthy in the graphics/gaming industry, my two cents won't make a difference.

[alipbcs]

Yes I'm aware that they're very useful and I'm interested in supporting them. But first I have to better understand how they're typically used. Could you make a video or point me to something that visually describes the workflow you're after?

[arconovum]

Here is a video where I am editing decals in my editor, they are multi-quad decal types. but dynamic mesh decals would be welcomed, the editor would generate the dynamic mesh, not the rendering engine.
https://youtu.be/wWa8LopZNjs?t=187

weird link does not work, you will need to cut and paste

https://youtu.be/wWa8LopZNjs?t=187

[alipbcs]

Thanks for the video. Could you explain how dynamic mesh decals would work? Any visual examples would be helpful.

[arconovum]

If I recollect In your engine I will be honest, all you need is mask / alpha texture to work fully, the meshes will be generated by the editor.

but if you really want an example : https://github.com/EricFreeman/DynamicDecals its in c# though

[alipbcs]

I see. Unfortunately, alpha textures are very expensive with RT. But maybe I can come up with new ideas to make them more efficient with decals. A few questions:

1. I'd need a test scene that uses decals. In the readme, there are a few screenshots of a subway scene that has decals -- are they representative of what you're after? Here's how they look like in Blender:

2. Is there a way for your editor to "mark" decal meshes to distinguish them from non-decal meshes?

[arconovum]

yes decal meshes in my editor are generated dynamically, as you move them the amount of affected surfaces changes, and require a dynamic approach for quad face creation. example , when you place a decal on a flat surface 1 quad is generated, but move it in corner (ceiling, + two wall faces) you get 3 quads for each surface hit, and more if more surfaces are hit ie: (subdiv surf), then the texture UV' are then generated.

Unfortunately, alpha textures are very expensive with RT
[EDIT] it would be a waste of a good rendering engine to not have an essential graphic primitive in it.

[alipbcs]

They're easy to implement, it's only a matter of performance. Newer NVIDIA GPUs have opacity micromap support, which makes alpha testing less expensive, but my GPU doesn't support it.

At least for decals, I should be able to come up with a workaround. May I ask how you pass the scenes from your editor to this renderer? Do you export to gltf and then import them in the renderer?

[arconovum]

No never IO, I do it by UDP , Its faster than HDD IO , but slower than an Plugin/API, but I like it because it shields my modeler from renderer crashes.

[alipbcs]

Have you implemented this type of integration to this renderer? Currently, some scene preprocessing happens during gltf import, so it's unlikely to work without some refactoring.

[arconovum]

No I am using another renderer, and yes refactoring is a reality, I have written an API for this other renderer, and an API for LuxCore Render, and yours is still in my sights as I want to support multiple renderers. And possibly Sicles.

[EDIT] I also had an API for nVidia Falcor , but development on Falcor has wained , so I abandoned it.

[alipbcs]

I see. I'll try to come up with a way to deal with decals. I've got a few ideas to try. I'll let you know how it goes.