Commit Graph

10 Commits

Author SHA1 Message Date
Brecht Van Lommel
de9dffc61e Cycles: initial subsurface multiple scattering support. It's not working as
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
2013-04-01 20:26:52 +00:00
Brecht Van Lommel
54729df020 Cycles OSL: diffuse_toon and specular_toon closures. These are toon shaders with
a size parameter between 0.0 and 1.0 that gives a angle of reflection between
0° and 90°, and a smooth parameter that gives and angle over which a smooth
transition from full to no reflection happens.

These work with global illumination and do importance sampling of the area within
the angle. Note that unlike most other BSDF's these are not energy conserving in
general, in particular if their weight is 1.0 and size > 2/3 (or 60°) they will
add more energy in each bounce.

Diffuse: http://www.pasteall.org/pic/show.php?id=42119
Specular: http://www.pasteall.org/pic/show.php?id=42120
2012-12-19 21:17:16 +00:00
Brecht Van Lommel
06888b7beb Cycles OSL minor optimizations: recycle shading context, don't do memory
allocations for trace data, avoid some virtual function calls. Only helps
a few percentages.
2012-12-15 10:18:42 +00:00
Brecht Van Lommel
5616c7a058 Cycles: disable scaling up of ray differentials after diffuse/glossy bounce, this
isn't working well for OSL texture filtering and wasn't very helpful to begin
with, a better solution should be possible.
2012-12-12 14:43:07 +00:00
Brecht Van Lommel
8d4bd2cf3b Cycles OSL: add diffuse_ramp closure in addition to phong_ramp. 2012-12-11 14:39:41 +00:00
Brecht Van Lommel
4c13633582 Fix #33334: missing glossy label for OSL phong ramp caused assert. 2012-11-28 16:42:32 +00:00
Brecht Van Lommel
209cd25745 Cycles OSL: phong_ramp(N, exponent, colors[8]) closure added, which works like
a specular ramp shader. Note this is OSL only still, for experimenting.

Patch by Thomas.
2012-11-06 19:59:07 +00:00
Brecht Van Lommel
27d647dcf8 Cycles: 4 new nodes.
* Tangent: generate a tangent direction for anisotropic shading. Can be either
  radial around X/Y/Z axis, or from a UV map. The default tangent for the
  anisotropic BSDF and geometry node is now always radial Z, for UV tangent use
  this node now.

http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/More#Tangent

* Normal Map: generate a perturbed normal from an RGB normal map image. This
  is usually chained with an Image Texture node in the color input, to specify
  the normal map image. For tangent space normal maps, the UV coordinates for
  the image must match, and the image texture should be set to Non-Color mode
  to give correct results.

http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/More#Normal_Map

* Refraction BSDF: for best results this node should be considered as a building
  block and not be used on its own, but rather mixed with a glossy node using a
  fresnel type factor. Otherwise it will give quite dark results at the edges for
  glossy refraction.

http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/Shaders#Refraction

* Ambient Occlusion: controls the amount of AO a surface receives, rather than
  having just a global factor in the world. Note that this outputs a shader and
  not a color, that's for another time.

http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/Shaders#Ambient_Occlusion
2012-11-06 19:59:02 +00:00
Brecht Van Lommel
615fe0295f Cycles OSL: refactoring and fixes
* Moved kernel/osl/nodes to kernel/shaders
* Renamed standard attributes to use geom:, particle:, object: prefixes
* Update stdosl.h to properly reflect the closures we support
* Fix the wrong stdosl.h being used for building shaders
* Add geom:numpolyvertices, geom:trianglevertices, geom:polyvertices attributes
2012-11-03 14:32:13 +00:00
Brecht Van Lommel
9a1c1f132d Cycles OSL: most closure code is now shared between OSL and SVM. Also fix
transmission pass and filter glossy option.

The BSDF closure class is now more similar to the SVM closures, and includes
some flags and labels that are needed to properly categorize the BSDF's for
render passes. Phong closure is gone for the moment, needs to be adapated to
the new structure still.
2012-10-20 12:18:00 +00:00