[Soc-2014-dev] Weekly Report #5 Cycles

[Thomas Dinges]

Hi,
here my report for week 5: 
http://wiki.blender.org/index.php/User:DingTo/GSoC_2014/Weekly_Reports/Week5

Best regards,
Thomas

= Week 5 =

== What I did this week ==
* Merged master into my branch (took some time, due to several 
conflicts) and updated QBVH Code in my Branch with the new SSE classes. 
(0e62c026ab3d, 611d69adb98b)

* Did some research and experiments on improved QBVH / Triangle 
Intersection again. https://developer.blender.org/D599 I think the 
"Watertight Ray/Triangle Intersection" paper + the Embree sample 
implementation of that is a very nice candidate, but probably a bit over 
my head for now. It involves changes to BVH build, BVH traversal and 
Triangle Intersection. Nevertheless would it be a great addition.
** Memory usage would be reduced (no more __tri_woop data, which would 
save us 4x float4 per triangle).
** Improved performance due to Quad BVH + multiple triangle 
intersections with SIMD.
** Also not sure how feasible that is for GPU. The algorithm itself does 
not use CPU only features as far as I can see that, but might need 
additional work.

* Started to look into ways to avoid unneeded samples for black 
backgrounds. http://www.pasteall.org/52361/diff I quickly hacked it in 
for the case, where "Use Nodes" is still disabled for the world. In the 
final implementation, I need to check the world shader tree, and extract 
the Background node, to see if the color is black or the strength zero. 
I am not exactly sure yet, how to do that. Help here is welcome.

* Today I spent time on the bugtracker.
** Fixed: Issue with Checker Texture, GLSL error with Hair shader: 
(ead83a48f15c, |a5a869c579de)
** Closed several other reports (Issues has been fixed, or not a bug).

== Next week ==
I will continue to work on the Background Sampling optimization or look 
into the Smooth Normals (as planned last week).

University exams start in 2 weeks (7 July - 17 July), so I would like to 
focus on that.
When I look at my proposal, half of the tasks are finished + WIP code 
for 2 more items is there. 
http://wiki.blender.org/index.php/User:DingTo/GSoC_2014/Proposal I also 
did additional work + fixes, that should be fine for Midterm I hope. :)
I can work almost full time on Cycles from the 18th July to GSoC end 
(18th August), that should give me enough time to finish my Deliverables 
+ some additional fun. But the upcoming 3-4 weeks will most likely be 
spend on University. Please tell me if that is ok.

== Questions ==
None.