opengl - What happens when a texture is too large for a device

The question is two fold:

1. 
   

   What happens on a device when a texture is too large for it to handle? Will it crash or simply downsize it?

   
   



2. 
   

   In Unity if I use texture atlases of size 4k and then set Texture Quality in the Quality settings as half res will it run normally on devices with maximum texture size of 2k?

   
   

Answer

According to this thread automatic downsizing may not work, but setting half res should work.

On a related note, do you really need textures that big? If all you want from a big texture is to use it as an atlas there is really very little reason to not just use 4 2k textures instead of one 4k.

And I assume that this is about writing games for phones, for PC graphics anything that doesn't support 4k textures is really ancient.