[Soc-2013-dev] Weekly Report #4: Cycles Motion Blur

[Gavin Howard]

All,

My report is at:
http://wiki.blender.org/index.php/User:Gdh/GSoC-2013#Weekly_Report_.234:_Cycles_Motion_Blur.

The text is also below.

== Weekly Report #4: Cycles Motion Blur ==

12 July 2013

==== What I did this week ====

''Yes!'' No major problems surfaced this week. After thinking it
through, I think that the merging problem was because I accidentally
had "clean whitespace" set on KDevelop. Even after I set it back,
there were problems. There were no problems merging this week, and
even if there had been, I have set up my system so I can do conflict
resolution by hand.

This week, I spent a lot of my time going through Cycles' Attributes
and family line of classes, trying to figure out ''what'' they do and
''how'' they do it. And even with all of that time spent, I am
stumped. I do know that the Attribute class has a vector of chars. It
also returns a char pointer when it returns the data contained in the
vector. The variable's name is "buffer", so I am assuming that the
vector of chars can actually be turned into any type of data. However,
assuming is never good.

At this point, I don't really know how I am going to extend the
Attribute and family line of classes to hold vertex blocks.

I did a couple of other things this week. First of all, I added two
new fields to the Object class: a bool for whether the object uses
deformation motion blur, and a uint for the number of motion blur
steps. I also managed to add code to get the viewport render to update
when those are changed. That made me especially happy because it told
me that the functions I wrote to pull those out of Blender both work.

I also started a design page on the wiki. As you can see by going
there, I stopped adding information to the Attributes section because,
quite frankly, I don't know what to do.

==== What I will do next week ====

Figure out just what Attribute and family do. Then I will add my
preliminary design to my design page (see above) and begin work in
earnest.

==== Questions ====

Can anyone explain in detail the Attributes and family architecture?
How they do what they do?

Also, I was thinking about storing the mesh copies in the Attributes,
and I think that exporting an odd number of meshes would be different
from exporting an even number of meshes. However, I am not completely
sure, considering that I don't know much about Attributes. Still, it
seems to me that an even number of meshes would dictate that we don't
even export the mesh at the "perfect" frame, while an odd number would
be different.

-- Gavin Howard, 12 July 2013