Tile texture goes pitch black when y-axis scaling is an extremely low value

[brnkhy]

This especially happens if you load the world in low zoom levels like 1 to 5. Root world object y-axis scale goes extremely low and unless TileSize is increased proportionally (i.e. using default 100), Unity cannot render the tile texture.
It renders if world scale y-axis is set to 1 (breaks heights of features&terrain) or TileSize increased to a much bigger number (like 1000 or 100000 depending on zoom level).

[david-rhodes]

Appears to be caused by internal floating point precision issues. As an alternative workaround, use an unlit material.

[david-rhodes]

@brnkhy Think we could just set a minimum y scale value?

[Spaxe]

I just bumped into potentially this issue ... but only on Windows 10, Unity 5.6.2f1. Pitch black.

On MacOS with Unity 5.6.1f1 this issue doesn't happen, although I did notice that at small tiles (say 0.5 TileSize), lighting doesn't quite work and I get a dim terrain.

Unlit is a workaround for now.

[wilhelmberg]

So far I've only come across that issue on one of my Android devices using Slippy demo.
Spent some hours fiddling with various settings and the combinations thereof.

Hope I haven't forgotten anything but these are the only changes needed for Slippy.unity (from develop) to consistently reproduce the issue on Samsung Tab S2 8".

Does not occur on OnePlus 3 or Windows native or Windows Store/UWP.

Camera position:

Map

• at 47.04071, 12.83326
• Zoom: 14

results in:

If I change SlippyTerrain/Factories/Resource/TerrainMaterial -> Shader to Unlit/color everything is white.
If I change it to Unlit/Texture ✅
If I change it to Unlit/Transparent ✅
If I change it to Unlit/Transparent Cutout ✅

If I change the shader back to Standard but set map zoom to 15 it also works:

[david-rhodes]

This is almost certainly related to a floating point precision issue, specifically in how lighting is calculated when the tiles are scaled so far down.

Another workaround is to increase the tile size when using lower zoom levels (this results in less transform scaling).

[david-rhodes]

Fixed: 032466b