This commit adds a new model to the Sky Texture node, which is based on a
method by Nishita et al. and works by basically simulating volumetric
scattering in the atmosphere.
By making some approximations (such as only considering single scattering),
we get a fairly simple and fast simulation code that takes into account
Rayleigh and Mie scattering as well as Ozone absorption.
This code is used to precompute a 512x128 texture which is then looked up
during render time, and is fast enough to allow real-time tweaking in the
viewport.
Due to the nature of the simulation, it exposes several parameters that
allow for lots of flexibility in choosing the look and matching real-world
conditions (such as Air/Dust/Ozone density and altitude).
Additionally, the same volumetric approach can be used to compute absorption
of the direct sunlight, so the model also supports adding direct sunlight.
This makes it significantly easier to set up Sun+Sky illumination where
the direction, intensity and color of the sun actually matches the sky.
In order to support properly sampling the direct sun component, the commit
also adds logic for sampling a specific area to the kernel light sampling
code. This is combined with portal and background map sampling using MIS.
This sampling logic works for the common case of having one Sky texture
going into the Background shader, but if a custom input to the Vector
node is used or if there are multiple Sky textures, it falls back to using
only background map sampling (while automatically setting the resolution to
4096x2048 if auto resolution is used).
More infos and preview can be found here:
https://docs.google.com/document/d/1gQta0ygFWXTrl5Pmvl_nZRgUw0mWg0FJeRuNKS36m08/view
Underlying model, implementation and documentation by Marco (@nacioss).
Improvements, cleanup and sun sampling by @lukasstockner.
Differential Revision: https://developer.blender.org/D7896
This patch will add some compiler hints to break unrolling in the
nestled for loops of the voronoi node.
Reviewed by: Brecht van Lommel
Differential Revision: https://developer.blender.org/D7574
This patch adds an AVX implementation of Perlin noise in Cycles.
An avxi type was also added as a utility based on the respective
type in Intel Embree.
Only 3D and 4D noise were implemented, there is no benefit for
utilizing AVX in 1D and 2D noise. The SSE trilinear interpolation
function was used in the AVX implementation because there is no
benefit from using AVX in interpolating the last three dimensions.
Differential Revision: https://developer.blender.org/D6680
The numbers here can probably be tweaked to be better, but it's hard to
predict and this should at least avoid excessive memory swapping.
Fixes T57064.
This feature takes some inspiration from
"RenderMan: An Advanced Path Tracing Architecture for Movie Rendering" and
"A Hierarchical Automatic Stopping Condition for Monte Carlo Global Illumination"
The basic principle is as follows:
While samples are being added to a pixel, the adaptive sampler writes half
of the samples to a separate buffer. This gives it two separate estimates
of the same pixel, and by comparing their difference it estimates convergence.
Once convergence drops below a given threshold, the pixel is considered done.
When a pixel has not converged yet and needs more samples than the minimum,
its immediate neighbors are also set to take more samples. This is done in order
to more reliably detect sharp features such as caustics. A 3x3 box filter that
is run periodically over the tile buffer is used for that purpose.
After a tile has finished rendering, the values of all passes are scaled as if
they were rendered with the full number of samples. This way, any code operating
on these buffers, for example the denoiser, does not need to be changed for
per-pixel sample counts.
Reviewed By: brecht, #cycles
Differential Revision: https://developer.blender.org/D4686
Some code was removed to avoid storing the combined pass when viewport
rendering other passes. But we can keep this by default, Blender overrides
the list of passes entirely.
The OptiX SRT motion expects a motion defined by translation,
rotation, shear and scale, but the matrix decomposition code in
Cycles was not able to extract shear information and instead
produced a stretch matrix with the information baked in. This
caused conflicting transforms between traversal and shading
and lead to render artifacts.
This patch changes the matrix decomposition to produce factors
inline with what OptiX expects to fix that.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D6605
In transform_motion_decompose, successive quaternion pairs are checked to be
aligned such that their interpolation is rotation through the shortest angle
between them. If not, the first in the pair was flipped. This can cause
problems for sequences of more than 2 quarternions, since flipping the first
in a pair might misalign the previously pair, if unlucky.
Instead, this change flips the second in the pair, which is safe when
iterating forwards.
Differential Revision: https://developer.blender.org/D6537
When creating shaders and using maths functions it is expected that Blender should match functions in other DCC applications, game engines and shading languages such as GLSL and OSL.
This patch adds missing functions to the Blender maths node.
Ideally, it would be nice to have these functions available to vectors too but that is not part of this patch.
This patch adds the following functions trunc, snap, wrap, compare, pingpong, sign, radians, degrees, cosh, sinh, tanh, exp, smoothmin and inversesqrt.
Sign function is based on GLSL and OSL functions and returns zero when x == 0.
Differential Revision: https://developer.blender.org/D5957
The Random Per Island attribute is a random float associated with each
connected component (island) of the mesh. It is particularly useful
when artists want to add variations to meshes composed of separate
units. Like tree leaves created using particle systems, wood planks
created using array modifiers, or abstract splines created using AN.
Reviewed By: Sergey Sharybin, Jacques Lucke
Differential Revision: https://developer.blender.org/D6154
This patch adds a new Vertex Color node. The node also returns the alpha
of the vertex color layer as an output.
Reviewers: brecht
Differential Revision: https://developer.blender.org/D5767
This patch allows the Voronoi node to operate in 1D, 2D, and 4D space.
It also adds a Randomness input to control the randomness of the texture.
Additionally, it adds three new modes of operation:
- Smooth F1: A smooth version of F1 Voronoi with no discontinuities.
- Distance To Edge: Returns the distance to the edges of the cells.
- N-Sphere Radius: Returns the radius of the n-sphere inscribed in
the cells. In other words, it is half the distance between the
closest feature point and the feature point closest to it.
And it removes the following three modes of operation:
- F3.
- F4.
- Cracks.
The Distance metric is now called Euclidean, and it computes the actual
euclidean distance as opposed to the old method of computing the squared
euclidean distance.
This breaks backward compatibility in many ways, including the base case.
Reviewers: brecht, JacquesLucke
Differential Revision: https://developer.blender.org/D5743
This patch rewrites the Mapping node to support dynamic inputs. The
Max and Min options have been removed. They can be added as Min and
Max Vector Math nodes manually.
Texture nodes still use the old matrix-based mapping. A new SVM node
`NODE_TEXTURE_MAPPING` has been added to preserve this functionality.
Similarly, in GLSL, a `mapping_mat4` function has been added.
Reviewers: brecht, JacquesLucke
This patch extends perlin noise to operate in 1D, 2D, 3D, and 4D
space. The noise code has also been refactored to be more readable.
The Color output and distortion patterns changed, so this patch
breaks backward compatibility. This is due to the fact that we
now use random offsets as noise seeds, as opposed to swizzling
and constants offsets.
Reviewers: brecht, JacquesLucke
Differential Revision: https://developer.blender.org/D5560
OpenCL Parallel compilation only works inside Blender. When using cycles in a different setup (standaline or other software) it failed compiling kernels as they don't have the appropriate Python API and command line arguments.
This change introduces a `running_inside_blender` debug flag, that triggers out of process compilation of the kernels. Compilation still happens in subthread that enabled the preview kernels and compilation of the kernels during BVH building
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D5439
This patch stitches the vertices along patch edges so that cracks can
no longer form when applying subdivision or displacement a mesh.
Subpatches are now formed in a way that ensures vertex indices along
subpatch edges are equal for adjacent subpatches. A mapping of vertices
along patch edges is built to preform stitching. Overall performance is
roughly the same, some gains were made in splitting, but some was lost
in stitching.
This fixes:
- T49049 (cracks between patches from material and uv seams)
- T49048 (discontinuous normals with true displacement)
Reviewers: sergey, brecht
Differential Revision: https://developer.blender.org/D3692
