[Soc-2013-dev] Weekly report #3 Cycles nodes

[Thomas Dinges]

Hi,
here my report for week 3:
http://wiki.blender.org/index.php/User:DingTo/GSoC_2013/Weekly_Reports/Week3

= Week 3 =

== What I did this week ==
* I finished the Vector Transform node, which is now working in both 
SVM/OSL, and it behaves identical. It took me some time to learn about 
the Transform matrices we have (especially the Object space transform 
case) but after some explanation by Brecht in IRC I understood the 
concept behind it.

* I also added two new nodes (as additional task), which have been 
requested by some artists: Separate / Combine HSV nodes. They are inside 
my branch as well. Screenshot: http://www.pasteall.org/pic/show.php?id=54828

* I started with the Ray Depth feature, and I have looked into 2 
different ways of implementing it:
** Ray Depth output inside the Light Path node. This way, we can get the 
current bounce (0, 1, 2...) as info output for the shader nodes.
WIP patch: http://www.pasteall.org/43776/diff
Example render: http://www.pasteall.org/pic/show.php?id=54930
Here we use the Ray Depth output (0 and 1 in this example) to apply 
different materials, and this way we see where we have a bounce and 
where only direct lighting is used. However, there are some weird 
artefacts, not sure what's going on here yet.

** Per shader bounce limiter. With this method, we can limit the ray 
bounces to an object on a per shader level, instead of only globally for 
the entire scene.
WIP patch: http://www.pasteall.org/43779/diff
Example render: http://www.pasteall.org/pic/show.php?id=54931
Here we have 3 spheres with a glass shader and (from left to right) 1, 2 
and 3 max bounces set per shader.

== Next week ==
I still have an exam next week, so will spend some time on preparations 
again. As I am done with all my nodes though, which was my goal for the 
first half of GSoC, I am far ahead in schedule.

I will keep working on the Ray depth feature next week and hopefully 
have a better implementation then.

== Questions ==
Mainly about the Ray Depth feature, am I on the right track with these 
or would another way of implementing them be better? And why do I have 
these artefacts with the feature as part of the Light Path node?

Best regards,
Thomas

-- 
Thomas Dinges
Blender Developer, Artist and Musician

www.dingto.org