Commit Graph

22 Commits

Author SHA1 Message Date
Thomas Dinges
ee36e75b85 Cleanup: Fix Cycles Apache header.
This was already mixed a bit, but the dot belongs there.
2014-12-25 02:50:24 +01:00
Thomas Dinges
bfdb9f9e0f Cycles: Remove Integrator volume sampling flag, that was moved to Shader. 2014-11-16 19:50:14 +01:00
Thomas Dinges
8243c55f14 Cycles: Split caustics option, to allow separate control for Reflection and Refraction caustics.
This way artists can only disable/enable refraction or reflection caustics.
See Cycles logs for an example: http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.72/Cycles

Differential revision: https://developer.blender.org/D766
2014-09-05 20:39:35 +02:00
Thomas Dinges
146a1c77ea Cleanup: Remove unused hardcoded variables in the integrator.
Differential Revision: https://developer.blender.org/D525
2014-05-12 10:45:11 +02:00
Thomas Dinges
211f08d89b Cycles: Direct multi light sampling in the Branched Path Integrator is optional now.
Disabling this can improve performance, when we need a lot of AA Samples anyway, to clear up the render.

Simple example .blend: http://www.pasteall.org/blend/27582

Differential Revision: https://developer.blender.org/D392
2014-03-15 17:37:43 +01:00
Thomas Dinges
99e20d7b89 Cycles: Option to Sample all Lights in the Branched Path integrator for indirect samples
This adds a new option "Sample All Lights" to the Sampling panel in Cycles (Branched Path). When enabled, Cycles will sample all the lights in the scene for the indirect samples, instead of randomly picking one. This is already happening for direct samples, now you can optionally enable it for indirect.

Example file and renders:
Blend file: http://www.pasteall.org/blend/27411
Random: http://www.pasteall.org/pic/show.php?id=68033
All: http://www.pasteall.org/pic/show.php?id=68034

Sampling all lights is a bit slower, but there is less variance, so it should help in situations with many lights.

Patch by myself with some tweaks by Brecht.
Differential Revision: https://developer.blender.org/D391
2014-03-09 22:20:01 +01:00
2bf591762a Cycles: equi-angular sampling for homogeneous volumes
This adds an option in the Volume Sampling panel, which helps rendering lamps
inside or near volumes with less noise. It can also increase noise though and
needs improvements to support MIS and heterogeneous volumes, but since it's
useful in some cases already (especially world volumes) it's there now.

Based on the code in the old branch by Stuart, with modifications by Thomas
and Brecht.

Differential Revision: https://developer.blender.org/D291
2014-02-14 17:37:34 +01:00
Thomas Dinges
e29a45b396 Cycles: Separation of Indirect and Direct clamping.
Indirect and Direct samples can now be clamped individually. This way we can clamp the indirect samples (fireflies), while keeping the direct highlights.
Example render: http://www.pasteall.org/pic/show.php?id=66586

WARNING: This breaks backwards compatibility. If you had Clamping enabled in an old file, you must re-enable either Direct/Indirect clamping or both again.

Reviewed by: brecht
Differential Revision: https://developer.blender.org/D303
2014-02-10 21:46:02 +01:00
01df756bd1 Cycles Volume Render: scattering support.
This is done by adding a Volume Scatter node. In many cases you will want to
add together a Volume Absorption and Volume Scatter node with the same color
and density to get the expected results.

This should work with branched path tracing, mixing closures, overlapping
volumes, etc. However there's still various optimizations needed for sampling.
The main missing thing from the volume branch is the equiangular sampling for
homogeneous volumes.

The heterogeneous scattering code was arranged such that we can use a single
stratified random number for distance sampling, which gives less noise than
pseudo random numbers for each step. For volumes where the color is textured
there still seems to be something off, needs to be investigated.
2014-01-07 15:03:41 +01:00
889d77e6f6 Cycles Volume Render: heterogeneous (textured) volumes support.
Volumes can now have textured colors and density. There is a Volume Sampling
panel in the Render properties with these settings:

* Step size: distance between volume shader samples when rendering the volume.
  Lower values give more accurate and detailed results but also increased render
  time.
* Max steps: maximum number of steps through the volume before giving up, to
  protect from extremely long render times with big objects or small step sizes.

This is much more compute intensive than homogeneous volume, so when you are not
using a texture you should enable the Homogeneous Volume option in the material
or world for faster rendering.

One important missing feature is that Generated texture coordinates are not yet
working in volumes, and they are the default coordinates for nearly all texture
nodes. So until that works you need to plug in object texture coordinates or a
world space position.

This is work by "storm", Stuart Broadfoot, Thomas Dinges and myself.
2013-12-30 00:04:02 +01:00
Brecht Van Lommel
01e22d1b9f Cycles: more code refactoring to rename things internally as well. Also change
property name back so we keep compatibility.
2013-08-23 14:34:34 +00:00
Brecht Van Lommel
b9ce231060 Cycles: relicense GNU GPL source code to Apache version 2.0.
More information in this post:
http://code.blender.org/

Thanks to all contributes for giving their permission!
2013-08-18 14:16:15 +00:00
Brecht Van Lommel
b20a7e01d0 Cycles: experimental correlated multi-jittered sampling pattern that can be used
instead of sobol. So far one doesn't seem to be consistently better or worse than
the other for the same number of samples but more testing is needed.

The random number generator itself is slower than sobol for most number of samples,
except 16, 64, 256, .. because they can be computed faster. This can probably be
optimized, but we can do that when/if this actually turns out to be useful.

Paper this implementation is based on:
http://graphics.pixar.com/library/MultiJitteredSampling/

Also includes some refactoring of RNG code, fixing a Sobol correlation issue with
the first BSDF and < 16 samples, skipping some unneeded RNG calls and using a
simpler unit square to unit disk function.
2013-06-07 16:06:22 +00:00
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
4ba456d175 Cycles: first step for implementation of non-progressive sampler that handles
direct and indirect lighting differently. Rather than picking one light for each
point on the path, it now loops over all lights for direct lighting. For indirect
lighting it still picks a random light each time.

It gives control over the number of AA samples, and the number of Diffuse, Glossy,
Transmission, AO, Mesh Light, Background and Lamp samples for each AA sample.

This helps tuning render performance/noise and tends to give less noise for renders
dominated by direct lighting.

This sampling mode only works on the CPU, and still needs proper tile rendering
to show progress (will follow tommorrow or so), because each AA sample can be quite
slow now and so the delay between each update wil be too long.
2012-06-13 11:44:48 +00:00
Brecht Van Lommel
1d8c798188 Cycles: support for motion vector and UV passes.
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.
2012-04-30 12:49:26 +00:00
Brecht Van Lommel
07b2241fb1 Cycles: merging features from tomato branch.
=== BVH build time optimizations ===

* BVH building was multithreaded. Not all building is multithreaded, packing
  and the initial bounding/splitting is still single threaded, but recursive
  splitting is, which was the main bottleneck.

* Object splitting now uses binning rather than sorting of all elements, using
  code from the Embree raytracer from Intel.
  http://software.intel.com/en-us/articles/embree-photo-realistic-ray-tracing-kernels/

* Other small changes to avoid allocations, pack memory more tightly, avoid
  some unnecessary operations, ...

These optimizations do not work yet when Spatial Splits are enabled, for that
more work is needed. There's also other optimizations still needed, in
particular for the case of many low poly objects, the packing step and node
memory allocation.

BVH raytracing time should remain about the same, but BVH build time should be
significantly reduced, test here show speedup of about 5x to 10x on a dual core
and 5x to 25x on an 8-core machine, depending on the scene.

=== Threads ===

Centralized task scheduler for multithreading, which is basically the
CPU device threading code wrapped into something reusable.

Basic idea is that there is a single TaskScheduler that keeps a pool of threads,
one for each core. Other places in the code can then create a TaskPool that they
can drop Tasks in to be executed by the scheduler, and wait for them to complete
or cancel them early.

=== Normal ====

Added a Normal output to the texture coordinate node. This currently
gives the object space normal, which is the same under object animation.

In the future this might become a "generated" normal so it's also stable for
deforming objects, but for now it's already useful for non-deforming objects.

=== Render Layers ===

Per render layer Samples control, leaving it to 0 will use the common scene
setting.

Environment pass will now render environment even if film is set to transparent.

Exclude Layers" added. Scene layers (all object that influence the render,
directly or indirectly) are shared between all render layers. However sometimes
it's useful to leave out some object influence for a particular render layer.
That's what this option allows you to do.

=== Filter Glossy ===

When using a value higher than 0.0, this will blur glossy reflections after
blurry bounces, to reduce noise at the cost of accuracy. 1.0 is a good
starting value to tweak.

Some light paths have a low probability of being found while contributing much
light to the pixel. As a result these light paths will be found in some pixels
and not in others, causing fireflies. An example of such a difficult path might
be a small light that is causing a small specular highlight on a sharp glossy
material, which we are seeing through a rough glossy material. With path tracing
it is difficult to find the specular highlight, but if we increase the roughness
on the material the highlight gets bigger and softer, and so easier to find.

Often this blurring will be hardly noticeable, because we are seeing it through
a blurry material anyway, but there are also cases where this will lead to a
loss of detail in lighting.
2012-04-28 08:53:59 +00:00
Brecht Van Lommel
6e93e33294 Cycles: add rejection of inf/nan samples, in principle these should not happen
but this makes it more reliable for now.

Also add an integrator "Clamp" option, to clamp very light samples to a maximum
value. This will reduce accuracy but may help reducing noise and speed up
convergence.
2012-04-05 15:17:45 +00:00
Brecht Van Lommel
b65061e2ae Cycles: code refactoring, to do render layer visibility test a bit different,
replacing the camera visibility flag with object layer flags.
2011-12-21 20:51:43 +00:00
Brecht Van Lommel
238f3a7d34 Cycles: seed value to get different noise values from renders, there was a patch
for this but I've implemented it differently.
2011-10-29 14:27:24 +00:00
Brecht Van Lommel
df625253ac Cycles:
* 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
2011-09-01 15:53:36 +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