利用者:DingTo/GSoC 2013/Weekly Reports/Week1

Week 1

Pre work

I started early with my GSoC, therefore I already finished some tasks before.

• Blackbody to RGB converter, to convert temperatures to a color. This node is inside my branch. I still have to figure out a problem with temperatures between 800 and 804 Kelvin, the lookup table does crazy stuff there. Example render: http://www.pasteall.org/pic/show.php?id=53582

• Toon Shader: The toon closure is finished and already in Trunk, it will be part of the Blender 2.68 release. Example render: http://www.pasteall.org/pic/show.php?id=51970

• Additionally, I added a Wavelength to RGB converter (in trunk as well), which can be uses to create interesting effects or simply to find the right color, by using a real world unit. Here a nice render by mfoxdogg: http://www.pasteall.org/pic/show.php?id=53746

What I did this week

• I started working on the Vector Transform node, to convert vectors and points between Object/World and Camera space. I added the UI and DNA/RNA code for it, the Cycles integration still needs to be done.

As I am mostly done with my Nodes, I spend some time on other Cycles tasks:

• Non-Progressive integrator has been enabled on GPU inside my branch. How this works out remains to be seen, it's probably not a good idea to bring this into trunk anytime soon, as it makes the GPU kernel about 2x as huge. Nevertheless, the Non-Progressive integrator has its strengths and if that works good on GPU (in my tests on a Geforce 540M it did), we should check on how we can get this feature into trunk. One idea would be to compile 2x kernels per architecture, Progressive and Non-Progressive integrator. We could split kernel_path.h into kernel_path_progressive.h and kernel_path_non_progressive.h and compile 2 entry points for the GPU.

• GPUs could only handle 95 textures and 5 HDR (float) image textures. This is a limitation of older Fermi cards, we have only 128 textures available there. For new Kepler cards though (sm_30 and sm_35), the new limit is 256 textures, so I increased the limit a bit for these architectures. We can now use 145 byte images and 5 float images (so 150 in total). This could be increased to about 200 if needed. It would be interesting to know if the change works on Kepler GPUs, I don't have such a card to test.

Next week

As I started earlier, I already have some things done, so I am good in time. I'd like to focus on exam preparation next week and maybe the week after. This has been discussed with my mentor Stuart. Nevertheless, I am confident to find some time to add some things during this time too, let's see.

Questions

No specifics at the moment, I started looking into BVH code and shader code for the "per object motion blur" and "ray depth" feature, but still have to read more code in order to understand the architecture well.