Fovmode horizontal

Bugs
1

Hi,

I ran into a problem with the horizontal fov mode for displaying gaussian mesh.
Depending on the window aspect ratio, the Gaussians appear very blurry in very wide windows. I’m attaching two screenshots and the PG :
GS FovMode Issue | Babylon.js Playground

image
image931×1080 233 KB

image
image931×486 100 KB

2

cc @Evgeni_Popov

3

Thanks for the report and the Playground!

This was a bug in the Gaussian splatting focal-length calculation when using Camera.FOVMODE_HORIZONTAL_FIXED. The vertical projection scale was multiplied by the viewport width, even though it already contained the aspect ratio. As a result, the aspect ratio was effectively applied twice and the splats became oversized and blurry on wide windows.

The fix computes the horizontal and vertical focal lengths independently from the camera projection matrix and viewport dimensions. It also preserves the existing fallback when no active camera is available and works with orthographic and multi-camera rendering.

PR: BabylonJS/Babylon.js#18921

PR snapshot: https://playground.babylonjs.com/?snapshot=refs/pull/18921/merge#PUWLG4#12