Now there is a single BVH traversal code with #ifdefs for various features.
At runtime it will then select the appropriate variation to use depending if
instancing, hair or motion blur is in use.
This makes scenes without hair render a bit faster, especially after the
minimum width feature was added. It's not the most beautiful code, but we can't
use c++ templates and there were already 4 copies, adding 4 more to handle the
hair case separately would be too much.
Code is added to restrict the pixel size of strands in cycles. It works best with ribbon primitives and a preset for these is included. It uses distance dependent expansion of the strands and then stochastic strand removal to give a fading. To prevent a slowdown for triangle mesh objects in the BVH an extra visibility flag has been added. It is also only applied for camera rays.
The strand width settings are also changed, so that the particle size is not included in the width calculation. Instead there is a separate particle system parameter for width scaling.
low roughness and same index of refraction.
Problem was bad float precision due to low roughness, which caused the pdf for
the different closures to not match properly.
well as I would like, but it works, just add a subsurface scattering node and
you can use it like any other BSDF.
It is using fully raytraced sampling compatible with progressive rendering
and other more advanced rendering algorithms we might used in the future, and
it uses no extra memory so it's suitable for complex scenes.
Disadvantage is that it can be quite noisy and slow. Two limitations that will
be solved are that it does not work with bump mapping yet, and that the falloff
function used is a simple cubic function, it's not using the real BSSRDF
falloff function yet.
The node has a color input, along with a scattering radius for each RGB color
channel along with an overall scale factor for the radii.
There is also no GPU support yet, will test if I can get that working later.
Node Documentation:
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/Shaders#BSSRDF
Implementation notes:
http://wiki.blender.org/index.php/Dev:2.6/Source/Render/Cycles/Subsurface_Scattering
* Enable Lamp MIS again, it works on a GTX 570 (which is sm_20) with latest SVN. Tested by vitos1k in IRC:.
Feedback from GTX 580 users would be appreciated on this.
The curve segment primitive has been added. This includes an intersection function and changes to the BVH.
A few small errors in the line segment intersection routine are also fixed.
* CUDA: Make it more clear that sm_12 and below is not supported.
* OpenCL: __KERNEL_SHADING__ was declared twice for nvidia opencl device.
* Some reshuffle of defines in kernel_types.h. No functional changes.
makes CPU kernel compilation much faster when using MSVC.
Sideeffect of this change is that CPU rendering is few percent
faster now. CUDA rendering is the same speed.
