[TRACKER] Rendering issues at very long distances (numerical precision)

[Flarkk]

This is a tracker dedicated to issues experienced when rendering at very long distances, i.e. involving very large camera far distance, very large and very far away geometry, lights with very long range, and all kinds of very large numbers in general.

Such scenes are very common in space settled games, open words, at-scale planets, and similar applications. Godot currently offers a rather low level of support for such applications due to the many places numerical precision and overflow issues arise.

Sometimes these issues can be worked around with the double precision build, but many also involve numerical issues in the shaders as well, which makes having double precision in the core engine of little help.

Note : deep scenes rendering usually comes along with other related requirements like floating origin management, quadtree / octree scene partitioning or resource streaming. These are broader concerns that go beyond rendering and should not be tracked here.

Feel free to comment on this thread if you've identified or resolved issues not yet mentioned below !

Issues classification

🌌 : happens at galactic scale (numbers > ~1e+19m). Most often related to overflows in length calculations and normalizations of 32 bit vectors.

🪐 : happens at planetary scale (numbers > ~1e+6m). Most often related to numerical precision issues with near and far planes of 32 bit projection matrices

🏞️ : happens at walkable distances (numbers > ~1e+2m). Not deep scene issues strictly speaking, still mentioned because likely related

Issues list

Scene

• [ ] 🪐 https://github.com/godotengine/godot-proposals/issues/10515 (#95944)
• [ ] 🪐 #55070 (#95944)
• [ ] 🪐 Camera far distance is limited to 1,000,000 in editor
• [ ] 🪐 Zoom in Editor is not fast enough at large scales. Related to https://github.com/godotengine/godot-proposals/issues/579

Lighting

• [ ] 🌌 Very far away point lights get culled (#98641)
• [ ] 🏞️ #89698
• [ ] 🏞️ #81772

  Shadows

• [ ] 🪐 #81877
• [ ] 🪐 Dual paraboloid texture may have NaN values for lights with very long range when blit from cubemap.
• [ ] 🪐 #92551
• [ ] 🏞️ #96361

Shading

Far away fragments

• [ ] 🌌 VIEW is NaN on very far away fragments (#95944)
• [x] 🪐 #86275

Geometry

• [ ] 🌌 Very large built-in sphere primitives have wrong normals (#98610)

Effects

• [ ] 🪐 #42390

[roalyr]

I've gathered all my tweaks in a single commit for 4.x : https://github.com/godotengine/godot/compare/master...roalyr:godot-for-3d-open-worlds:master and for 3.x: https://github.com/godotengine/godot/compare/3.x...roalyr:godot-for-3d-open-worlds:3.x Just in case. I also think it is worth adding editor tweaks to the list (scene camera and in-game camera limits, editor zooming speed, grid and gizmos rendering precision, and so on).

[Zireael07]

Nit: I'd change the title to be "very large", as "deep" usually refers to the scene tree's complexity