Commit Graph

16 Commits

Author SHA1 Message Date
Stuart Broadfoot
638b084f82 Cycles Hair: Strand Minimum Pixel Size
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.
2013-04-15 21:38:31 +00:00
Brecht Van Lommel
bf25f1ea96 Cycles Hair: refactoring to store curves with the index of the first key and the
number of keys in the curve, rather than curve segments with the indices of two
keys. ShaderData.segment now stores the segment number in the curve.
2013-01-03 12:09:09 +00:00
Brecht Van Lommel
57cf48e7c6 Cycles Hair: refactoring to support generic attributes for hair curves. There
should be no functional changes yet. UV, tangent and intercept are now stored
as attributes, with the intention to add more like multiple uv's, vertex
colors, generated coordinates and motion vectors later.

Things got a bit messy due to having both triangle and curve data in the same
mesh data structure, which also gives us two sets of attributes. This will get
cleaned up when we split the mesh class.
2013-01-03 12:08:54 +00:00
Stuart Broadfoot
e9ba345c46 New feature
Patch [#33445] - Experimental Cycles Hair Rendering (CPU only)

This patch allows hair data to be exported to cycles and introduces a new line segment primitive to render with.

The UI appears under the particle tab and there is a new hair info node available.

It is only available under the experimental feature set and for cpu rendering.
2012-12-28 14:21:30 +00:00
Campbell Barton
353ad46e10 code cleanup: quiet double promotion warnings 2012-11-07 23:52:33 +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
2ba840652d Cycles: improve Anisotropic BSDF node, changing the Roughness U/V inputs to
Roughness, Anisotropy and Rotation. Also a fix for automatic tangents and
OSL attribute handling.

Meaning of new sockets explained in the documentation:
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/Shaders#Anisotropic
2012-11-04 22:31:32 +00:00
Brecht Van Lommel
9db3f2368c Cycles: use mikktspace now for computing tangents from UV maps. This avoids ugly
averaged tangents at UV seams but instead now the seams will show as discontinuities
in the tangent.
2012-11-03 15:36:02 +00:00
Brecht Van Lommel
9d260eedeb Fix #32904: strange pattern on subdivided cube with anistropic shader. Now
tangents from generated coordinates are computed per pixel on the fly, avoids
bad interpolation of singularities.
2012-10-17 23:09:12 +00:00
Brecht Van Lommel
51105bb2bd Fix for wrong cycles tangent in some cases, was missing transform. 2012-10-13 12:11:01 +00:00
Brecht Van Lommel
f0a9b66469 Cycles: Anisotropic BSDF enabled, with tangents now computed from the active UV map.
It's using the Ward BSDF currently, which has some energy loss so might be a bit
dark. More/better BSDF options can be implemented later.

Patch by Mike Farnsworth, some modifications by me. Currently it's not possible yet
to set a custom tangent, that will follow as part of per-bsdf normals patch.
2012-10-10 13:02:20 +00:00
Lukas Toenne
9e3fa15d4b Added a bunch of additional particle state attributes to the Cycles particle info node:
* Location: Basically the same as the location from Object Info node for object instances on particles, but in principle there could be additional offsets for dupli objects, so included for completeness.
* Size: Single float scale of the particle. Also directly translates to object scale for current dupli objects, but handy to have as a single float to start with instead of a scale vector (currently not even exposed in Object Info).
* Rotation: This is a quaternion, which are not yet supported by Cycles nodes. The float4 is copied to internal Cycles data and stored in the particles texture data, but the node doesn't have a socket for it yet and the data is not yet written to the stack. Code is just commented out so could be enabled quickly if/when rotation support is added to cycles.
* Velocity: Linear velocity vector of particles.
* Angular Velocity: Angular velocity around principle axes.

The texture data is currently packed tightly into the particles texture, which saves a few bytes, but requires an additional texture lookup for some vector attributes which spread over two float4s. Could also add another float4 to particle size to avoid this.
2012-08-31 19:38:59 +00:00
Lukas Toenne
fec872ef9c Added a particle index output to the Particle Info Cycles node. This is required to get consistent ID numbers for particles. The Object ID is not usable since it's a user defined value of the instanced object, which does not vary per instance. Also the random value from the object info node is not consistent over time, since it only depends on the index in the dupli list (so each emitted or dying particle shifts the value).
The particle index is always the same for a specific particle. Randomized values can be generated from this with the use of a noise texture.
2012-07-26 11:40:58 +00:00
Lukas Toenne
5e1bbde01d Particle Info node for Cycles. This can be used to access particle information in material shaders for dupli objects. For now only the particle Age and individual Lifetime (in frames) are supported, more attributes can be added when needed.
The particle data is stored in a separate texture if any of the dupli objects uses particle info nodes in shaders. To map dupli objects onto particles the store an additional particle_index value, which is different from the simple dupli object index (only visible particles, also works for particle dupli groups mode).

Some simple use cases on the code.blender.org blog:
http://code.blender.org/index.php/2012/05/particle-info-node/
2012-06-08 16:17:57 +00:00
Brecht Van Lommel
c3e1fce775 Cycles: add Object Info node, with outputs object location, object/material
pass index, and a random number unique to the instance of the object.

This can be useful to give some variation to a single material assigned to
multiple instances, either manually controlled through the object index, based
on the object location, or randomized for each instance. 

http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/More#Object_Info
2012-05-21 12:52:28 +00:00
Ton Roosendaal
da376e0237 Cycles render engine, initial commit. This is the engine itself, blender modifications and build instructions will follow later.
Cycles uses code from some great open source projects, many thanks them:

* BVH building and traversal code from NVidia's "Understanding the Efficiency of Ray Traversal on GPUs":
http://code.google.com/p/understanding-the-efficiency-of-ray-traversal-on-gpus/
* Open Shading Language for a large part of the shading system:
http://code.google.com/p/openshadinglanguage/
* Blender for procedural textures and a few other nodes.
* Approximate Catmull Clark subdivision from NVidia Mesh tools:
http://code.google.com/p/nvidia-mesh-tools/
* Sobol direction vectors from:
http://web.maths.unsw.edu.au/~fkuo/sobol/
* Film response functions from:
http://www.cs.columbia.edu/CAVE/software/softlib/dorf.php
2011-04-27 11:58:34 +00:00