Circular mask-like rendering artifact appears while zooming at a low camera angle

[TQtong]

What happened?

A circular or elliptical mask-like rendering artifact appears on the globe while zooming the camera at a low, oblique viewing angle.

The imagery inside the affected circular area has a different brightness or color from the surrounding imagery. The boundary of the artifact is curved and resembles a large circular mask projected onto the globe.

Reproduction steps

1. Open a CesiumJS Viewer with globe imagery enabled.
2. Move the camera to a low, oblique angle near the horizon.
3. Position the camera over the Great Lakes region, as shown in the attached screenshots.
4. Zoom in or out using the mouse wheel.
5. Observe the circular or elliptical mask-like artifact appearing on the globe during zooming.

Sandcastle example

https://sandcastle.cesium.com/#c=bY1BawIxEIX/ypCTlpLg2exS8Cr0UPA0l5gd69DZiWSyK/bXF7VCCx7f4/ve4/FUaoMXSAYbMp5GONQyArp8S+jWqKi5qDWYmc5UoQOl8y/td7du8eA3RVtipYpuuUZ1ry5auwj1qABvfH+bqiy8D43Gk6RGFvZT/qLms9lViuGhxIFn4KF7sg5ZklmH7jCJfPA3oetjGHj+p0lJA+vn+0xV0uWKHFf99l5672M4rp5YrRTZp/pn8Qc

Environment

Browser: 151.0.7922.77
CesiumJS Version: 1.144.0
Operating System: Windows 11

AI acknowledgment

• I used AI to generate this issue report.
• (If the above is checked) I have reviewed the AI-generated content before submitting.

[TQtong]

After testing, I identified two issues: atmospheric rendering and fog. These two effects are responsible for what you see in the image. This images illustrates the issue more clearly