2D optimizations issue on Adreno ("SnapDragon") GPUs

[nx7r]

Godot version

4.0 rc3

System information

SD 860, SD 665, SD 662, GL/Mobile rendering device

Issue description

When any kind of 2D light is added to the scene, the frame rate drops to 9fps

Note : My device xiaomi POCO X3 Pro

Steps to reproduce

1. add PointLight2D to the scene
2. export the project to Android device wich have a SnapDragon CPU
3. than all magic will happen (fps drops)

==> Running this demo on that devices will make the same issue:
https://github.com/godotengine/godot-demo-projects/tree/master/2d/lights_and_shadows

Minimal reproduction project

https://github.com/godotengine/godot-demo-projects/tree/master/2d/lights_and_shadows

[clayjohn]

Have you tested both the mobile renderer and the gl_compatibility renderer? Note: you have to change the rendering_method.mobile setting in order to change the renderer on mobile. Changing just rendering_method isn't enough

[nx7r]

@clayjohn Yes, I have tested both mobile and gl_compatibility renderer.

[clayjohn]

And you are getting exactly 9 FPS on both backends?

[nx7r]

@clayjohn not exactly: fps_range[9, 18]

[Calinou]

Can you reproduce this with a lower rendering resolution? Set the stretch mode to viewport in the project settings (ensure it's saved to project.godot), then export the project to Android again.

I get a feeling we should implement 2D resolution scaling like we did for 3D, as rendering lights at full resolution on mobile is very expensive in terms of fillrate.

[clayjohn]

Tested on an Adreno 640 device and had a consistent 11-12 FPS, with #100302 its now locked at 60 FPS