This now supports multiple steps and subframe sampling of motion.
There is one difference for object and camera transform motion blur. It still
only supports two steps there, but the transforms are now sampled at subframe
times instead of the previous and next frame and then interpolated/extrapolated.
This will give different render results in some cases but it's more accurate.
Part of the code is from the summer of code project by Gavin Howard, but it has
been significantly rewritten and extended.
Problem is that the particle systems in the cycles database are not
stored in a well-defined order. This means the particle_id for dupli
objects can not simply be assigned using a global running index during
sync.
Now the particle index is assigned locally for each particle system.
When transferring particle data to the device as a single texture, the
particle indices are offset based on the final order of particle systems
in the database.
Reviewers: brecht
Reviewed By: brecht
CC: Andreas80
Differential Revision: https://developer.blender.org/D352
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.
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.
Also some simple OSL optimization, passing thread data pointer directly instead
of via thread local storage, and creating ustrings for attribute lookup.
Generated and UV coordinates from the duplicator of instance instead of the
object itself.
This was used in e.g. Big Buck Bunny for texturing instanced feathers with
a UV map on the bird. Many files changed, mainly to do some refactoring to
get rid of G.rendering global in duplilist code.
The particle data used by the Particle Info node was stored in cycles as a list in each object. This is a problem when the particle emitter mesh is hidden: Objects in cycles are only intended as instances of renderable meshes, so when hiding the emitter mesh the particle data doesn't get stored either. Also the particle data can potentially be copied to multiple instances of the same object, which is a waste of texture space.
The solution in this patch is to make a completely separate list of particle systems in the Cycles scene data. This way the particle data can be generated even when the emitter object itself is not visible.
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/
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
Most of the changes are related to adding support for motion data throughout
the code. There's some code for actual camera/object motion blur raytracing
but it's unfinished (it badly slows down the raytracing kernel even when the
option is turned off), so that code it disabled still.
Motion vector export from Blender tries to avoid computing derived meshes
when the mesh does not have a deforming modifier, and it also won't store
motion vectors for every vertex if only the object or camera is moving.
Currently supported passes:
* Combined, Z, Normal, Object Index, Material Index, Emission, Environment,
Diffuse/Glossy/Transmission x Direct/Indirect/Color
Not supported yet:
* UV, Vector, Mist
Only enabled for CPU devices at the moment, will do GPU tweaks tommorrow,
also for environment importance sampling.
Documentation:
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Passes
* Add max diffuse/glossy/transmission bounces
* Add separate min/max for transparent depth
* Updated/added some presets that use these options
* Add ray visibility options for objects, to hide them from
camera/diffuse/glossy/transmission/shadow rays
* Is singular ray output for light path node
Details here:
http://wiki.blender.org/index.php/Dev:2.5/Source/Render/Cycles/LightPaths
