gltf format models are not displayed correctly (and not only)

[DearFox]

Describe the bug It seems the polygons are not sorted in the correct order, which is why the model looks very strange.

To Reproduce Steps to reproduce the behavior:

1. Open the file using f3d.exe
2. Drag and drop the model in gltf format created via BlockBench there

4. done

Expected behavior Correct display of polygons in the correct order

System Information:

• OS: Windows 10 x64
• GPU and GPU driver: NVIDIA GeForce GTX 1050 Driver version: 31.0.15.3129

F3D Information F3D 2.2.1

F3D - A fast and minimalist 3D viewer Version: 2.2.1. Build date: 2023-10-04 12:20:14. Build system: Windows 64-bits. Compiler: MSVC 19.35.32217.1. External rendering module: ON. Raytracing module: OFF. VTK version: 9.3.0.rc0-514-g1a5445687f (date: 20230922). Copyright (C) 2019-2021 Kitware SAS. Copyright (C) 2021-2023 Michael Migliore, Mathieu Westphal. License BSD-3-Clause. By Michael Migliore, Mathieu Westphal and Joachim Pouderoux.

Additional context I'm not exactly sure, but it looks like the shaders are wrong or something. I noticed similar behavior when setting up shaders in Blender when I needed an alpha channel on a texture, but I don't understand much about it. Typically gltf models work fine. Here are the models from the screenshots that I tried to open, but all my gltf format models have this strange display (they were all exported from Blockbench) 3D model.zip

[DearFox]

It seems this happens not only with gltf (

[Meakk]

Can you try to press P in f3d?

[DearFox]

Can you try to press P in f3d?

Seems better but still has some artifacts And can I enable this by default, and for thumbnails?

[mwestphal]

can I enable this by default, and for thumbnails?

Sure, using the configuration file: https://f3d.app/doc/user/CONFIGURATION_FILE.html

In short, copy the config folders from

C:/Program Files/F3D/share/f3d/configs/

to

%APPDATA%\f3d\

And modify the config.d/10_global.json and thumbnail.d/10_global.json and add the following:

"translucency-support": true, before the first option, like this:

{
  "global":
  {
   "translucency-support": true,
    "axis": true,
    "tone-mapping": true,
    "grid": true,
    "progress": true,
    "anti-aliasing": true,
    "filename": true,
    "scalars": "", 
    "camera-direction": "-1,-0.5,-1",
    "hdri-ambient": true
  }
}

Any remaining issue are probably caused by issues on your data. If you think this is not the case, please let us know!

@Meakk should we turn this on after all ? Not the first user to get surprised by this.

[mwestphal]

input @Meakk ?

[Meakk]

Depth peeling is a bit expensive and will cause a drop of fps. The issue is some gltf file exporter just flag material as BLEND instead of OPAQUE but that's the exporter fault.
However, if the materials are properly flagged as opaque, there won't be any fps drop so I think it's ok to enable depth peeling for gltf files (or even globally)

[mwestphal]

Indeed, I think that displaying, by default, a BLEND material without its opacity is a bug, so we should enable depth peeling globally, as long as it does not implies slow down for user not using transparent material.

Lets keep this issue open to do the change.