[Soc-2012-dev] GSOC 2012 Texture/UV tools development report 2

[Antony Riakiotakis]

What you did this week
====================
Worked more on uv transform tool and managed to make a first working
version of the tool on Wednesday. Thursday and Friday were spent on
ways to make the tool better. Today I did quite a lot of tests and
math trying to figure out a good way to solve the problem even better.
There are some glimplses of good results but in general I need to
tweak the code more. Also some bugs remain, for instance on
proportional edit, which I hope to also make functional when working
with the tool, and support for stitches, which should be
straightforward once I add some extra initialization code.

Next week
============
I hope to do more tests during the weekend on uv transform tool if I
can but next I will eventually move on to texture paint code as per
the schedule. If all goes well I will have at least anchor or rake
brushes functional by the end of the week

Problems so far
===============
UV transform tool has proved quite a challenge so far. The issue is
making a uv tweak that looks and works well. The current code will
work when the edges connected to a vertex are more or less
perpendicular. It actually does an average sum of uv edge diffs, based
on the ratio of the modified edge lengths to the initial edge lengths
but I wanted to make the code select the face that is closer to the
moved vertex and modify the result based on that. Today I did some
progress but the result is jumpy, probably due to sloppy
projection/angle calculation code that I will have to review. The
biggest issue that I have so far is finding easily if a vertex is
inside a face in 3D space. I have formulated a method using cross
product of face normal and loops that looks like it will work but i
will have to work on it some more to handle corner cases such as loops
parallel to each other and translation of a vertex outside a face (see
boundary of a mesh). I am optimistic though :)