[Bf-committers] GSoC 2016 - Improve Undo Memory Usage for Mesh Data

[Nuno Lopes]

Hello Developers !

I am Nuno Lopes and I'm in second year of Computer Science in Universidade
de Evora, Portugal.

I was looking for blender ideas for this year for google summer of code and
I found this one that i thought interesting but didn't understand how does
it store by looking to is description:

"Blender’s undo currently compares memory, only storing arrays which
differ, however for editing a mesh -
adding or deleting a single vertex will cause the data to differ, causing
the undo to store a lot of data for each operation."

I didn't understand how it stores, for example:
I have the initial cube when blender starts:
     _______
    /      /|
   /______/ |
   |      | |
   |      | /
   |______|/

   Are all 8 vertices and 6 faces stored?
   Then I delete the 4 top vertices, does it store what I deleted(4 top
vertices, 8 edges and 5 faces) or what still remains(4 bot vertices, 4
edges, 1 face) ?

Best regards,
Nuno Lopes