Sparse Texture

I want to implent the OpenGL sparse texture to panda3d:

Sparse Virtual Texturing is an approach to simulating very large textures using much less texture memory than they'd require in full by downloading only the data that is needed, and using a pixel shader to map from the virtual large texture to the actual physical texture.

Demo: … 9vOX-_LyU#
Detailed information:
OpenGL Specification: … exture.txt
DirectX Specification (only 11.2):
Some related tutorial: … ter37.html

Basically, with sparse textures, you can have textures of a huge size (e.g. 32x32k), and only the current visible area is streamed.

I want (or at least try) to implement this feature … but where In the panda3d source shall I start? Which files would be affected?

Thanks in advance