due to jittering of the start position for antialiasing in a pixel.
Now it distributes the start position over the fixed osa sample
positions, instead of of random positions in space. The ugly bit is
that a custom ordering was defined for osa 8/11/16 to ensure that the
first 4 are distributed relatively fair for adaptive sampling to decide
if more samples need to be taken.
the renderer could lead to results being reused for unrelated
points, result was one wrong pixel or strand per part. Now instead
of setting the sample counter to 0 multiple times, it keeps a global
counter per thread for the whole render.
This completes the pipeline make-over, as started in 2006. With this
option, during rendering, each sample for every layer and pass is being
saved on disk (looks like non-antialiased images). Then the composite
and color correction happens, then a clip to 0-1 range, and only in end
all samples get combined - using sampling filters such as gauss/mitch/catmul.
This results in artefact-free antialiased images. Even Z-combine or
ID masks now work perfect for it!
This is an unfinished commit btw; Brecht will finish this for strands.
Also Halo doesnt work yet.
To activate FSA: press "Save Buffers" and the new button next to it. :)
=============================
A new approximate ambient occlusion method has been added, next to the
existing one based on raytracing. This method is specifically targetted
at use in animations, since it is inherently noise free, and so will
not flicker across frames.
http://www.blender.org/development/current-projects/changes-since-244/approximate-ambient-occlusion/http://peach.blender.org/index.php/approximate-ambient-occlusion/
Further improvements are still needed, but it can be tested already. There
are still a number of known issues:
- Bias errors on backfaces.
- For performance, instanced object do not occlude currently.
- Sky textures don't work well, the derivatives for texture evaluation
are not correct.
- Multiple passes do not work entirely correct (they are not accurate
to begin with, but could be better).
=================
Big commit, but little user visible changes.
- Dupliverts and duplifaces are now rendered as instances, instead
of storing all of the geometry for each dupli, now an instance is
created with a matrix transform refering to the source object.
This should allow us to render tree leaves more memory efficient.
- Radiosity and to some degree raytracing of such objects is not
really efficient still. For radiosity this is fundamentally hard
to solve, but raytracing an octree could be created for each object,
but the current octree code with it's fixed size doesn't allow this
efficiently.
- The regression tests survived, but with I expect that some bugs will
pop up .. hopefully not too many :).
Implementation Notes
====================
- Dupligroups and linked meshes are not rendered as instances yet,
since they can in fact be different due to various reasons,
instancing of these types of duplis that are the same can be added
for them at a later point.
- Each ObjectRen now stores it's own database, instead of there being
one big databases of faces, verts, .. . Which objects that are actually
rendered are defined by the list of ObjectRenInstances, which all refer
to an ObjectRen.
- Homogeneous coordinatess and clipping is now not stored in vertices
anymore, but instead computed on the fly. This couldn't work for
instances. That does mean some extra computation has to be done, but
memory lookups can be slow too, and this saves some memory. Overall
I didn't find a significant speed impact.
- OSA rendering for solid and ztransp now is different. Instead of e.g.
going 8 times over the databases times and rendering the z-buffer, it
now goes over the database once and renders each polygon 8 times. That
was necessary to keep instances efficient, and can also give some
performance improvement without instances.
- There was already instancing support in the yafray export code, now it
uses Blender's render instances for export.
- UV and color layer storage in the render was a bit messy before, now
should be easier to understand.
- convertblender.c was reorganized somewhat. Regular render, speedvector
and baking now use a single function to create the database, previously
there was code duplicated for it.
- Some of these changes were done with future multithreading of scene
and shadow buffer creation in mind, though especially for scene creation
much work remains to be done to make it threadsafe, since it also involves
a lot of code from blenkernel, and there is an ugly conflict with the way
dupli groups work here .. though in the render code itself it's almost there.
=========
- Fix crash in particle transform with the particle system not editable.
- Particle child distribution and caching is now multithreaded.
- Child particles now have a separate Render Amount next to the existing
Amount. The render amount particles are now only distributed and cached
at render time, which should make editing with child particles faster.
- Two new options for diffuse strand shading:
- Surface Diffuse: computes the strand normal taking the normal at
the surface into account.
- Blending Distance: the distance in Blender units over which to
blend in the normal at the surface.
- Special strand rendering for more memory efficient and faster hair and
grass. This is a work in progress, and has a number of known issues,
don't report bugs to me for this feature yet.
More info:
http://www.blender.org/development/current-projects/changes-since-244/particles/
Added support for multiple UVs in the render engine. This also involved
changing the way faces are stored, to allow data to be added optionally
per 256 faces, same as the existing system for vertices.
A UV layer can be specified in the Map Input panel and the Geometry node
by name. Leaving this field blank will default to the active UV layer.
Also added sharing of face selection and hiding between UV layers, and at
the same time improved syncing with editmode selection and hiding.
Still to do:
- Multi UV support for fastshade.
- Multires and NMesh preservation of multiple UV sets.
- Bug: material emit was ignored (showed in preview render backdrop)
- Bug: world exposure was ignored
- Bug: lamp halo was ignoring 'render layer light override'.
Further reshuffled the way shadows are being pre-calculated, this to enable
more advanced (and faster) usage of Material lightgroups. Now shadows are
being cached in lamps, using a per-sample counter to check if a recalc is
needed. Will also work (later) for Raytracing node shaders.
- New: Material LightGroup option "Always", which always shades the lights
in the group, independent of visibility layer. (so it allows to move such
lights to hidden layer, not influencing anything).
