Offscreen rendering not working properly

[elias-Mimetrik]

⚠️ Issues not using this template will be systematically closed.

Describe the bug
Offscreen rendering is producing completely black images.

To Reproduce

An example of this failure occurs when using the frame_generator example. To reproduce:

1. Build filament library.

2. Generate a material using matc tool, for example:

./matc --api all -o ./plastic.filamat plastic.mat

3. Use this material in the frame_generator tool, and use params.txt file containing only roughness 0.0 1.0:

./frame_generator --material="plastic.filamat" --params=./params.txt --api=opengl --scale=0.1 -l -c 10 donut.obj

The result from the command above will be completely black:

However, if opengl option is replaced with vulkan, the mesh is rendered but without the skybox:

Expected behavior
The mesh should be rendered fine in opengl as well as vulkan along with the skybox, but it does not render at all in opengl and the skybox is not rendered in vulkan

Screenshots
Screenshots added above.

Logs
Output when using vulkan:

FEngine (64 bits) created at 0x62cb0e9e87a0 (threading is enabled)
Vulkan device driver: NVIDIA 565.57.01
Selected physical device 'NVIDIA GeForce RTX 4080 Laptop GPU' from 3 physical devices. (vendor 0x10de, device 0x27e0, driver 0x8d4e4040, api 1.3)
Backend feature level: 3
FEngine feature level: 3

Output when using opengl:

FEngine (64 bits) created at 0x6272196b6f80 (threading is enabled)
FEngine resolved backend: OpenGL
Backend feature level: 3
FEngine feature level: 3

Desktop (please complete the following information):

• OS: ubuntu 24.04
• GPU: NVIDIA GeForce RTX 4080
• Backend: OpenGL & Vulkan

Smartphone (please complete the following information):

• Device: [e.g. Pixel 2]
• OS: [e.g. Android Pie 9.0]

Additional context

[pixelflinger]

I just tried all backends on my macbook and it's all working. So it might be a gpu specific issue.
Can you provide the material and .obj file you used?