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.. _bpy.types.ShaderNodeTexGabor:
.. section-title
******************
Gabor Texture Node
******************
.. figure:: /images/node-types_ShaderNodeTexGabor.webp
:align: right
:alt: Gabor Texture Node.
The *Gabor Texture* node evaluates a Gabor noise at the input texture coordinates. Gabor noise is
visually characterized by random interleaved bands whose direction and width can be controlled.
Additionally, it can be used to create omnidirectional noise like the standard Noise Texture node,
but since it is more expensive to compute, using the Noise Texture node is probably the better
option in those cases. See the examples for more information.
.. section-inputs
Inputs
======
Vector
The coordinates at which Gabor noise will be evaluated. The Z component is ignored in the 2D
case. Defaults to *Generated* texture coordinates if the socket is left unconnected.
Scale
Scale of the Gabor noise.
Frequency
The rate at which the Gabor noise changes across space. This is different from the Scale input
in that it only scales perpendicular to the Gabor noise direction.
Anisotropy
The directionality of Gabor noise. 1 means the noise is completely directional, while 0 means
the noise is omnidirectional.
Orientation
The direction of anisotropic Gabor noise. This is an angle for the 2D case, while it is a unit
direction vector for the 3D case.
Properties
==========
Type
Type of Gabor noise texture.
:2D:
Evaluates the noise in 2D space. The Z component of the input vector is ignored.
:3D:
Evaluates the noise in 3D space.
.. note::
Higher dimensions corresponds to higher render time, so lower dimensions should be used
unless higher dimensions are necessary.
Outputs
=======
Value
The Gabor noise value with both random intensity and phase. This is equal to sine the phase
multiplied by the intensity.
Phase
The phase of the Gabor noise, which has no random intensity.
Intensity
The intensity of the Gabor noise, which has no random phase.
Examples
========
The following table demonstrates different outputs of the node with different parameters. As can be
seen, the noise is visually characterized by interleaved bands that are generally oriented in a
specific direction. But the *Anisotropy* parameter can be decreased below 1 to make the bands more
random in directions. The *Frequency* parameter determines the number of bands perpendicular to the
direction of the noise. However, the *Scale* parameter can also be used to globally increase the
number of bands, so consider increasing the scale first since high frequency noise can suffer from
low contrast and limited interleaving of bands.
.. list-table:: Different outputs with different parameters.
* - .. figure:: /images/render_shader-nodes_textures_gabor_example-value.jpg
:width: 320px
Value output. Frequency = 2. Anisotropy = 1.
- .. figure:: /images/render_shader-nodes_textures_gabor_example-phase.jpg
:width: 320px
Phase output. Frequency = 2. Anisotropy = 1.
- .. figure:: /images/render_shader-nodes_textures_gabor_example-intensity.jpg
:width: 320px
Intensity output. Frequency = 2. Anisotropy = 1.
* - .. figure:: /images/render_shader-nodes_textures_gabor_example-value-high-frequency.jpg
:width: 320px
Value output. Frequency = 3. Anisotropy = 1.
- .. figure:: /images/render_shader-nodes_textures_gabor_example-phase-high-frequency.jpg
:width: 320px
Phase output. Frequency = 3. Anisotropy = 1.
- .. figure:: /images/render_shader-nodes_textures_gabor_example-intensity-high-frequency.jpg
:width: 320px
Intensity output. Frequency = 3. Anisotropy = 1.
* - .. figure:: /images/render_shader-nodes_textures_gabor_example-value-isotropic.jpg
:width: 320px
Value output. Frequency = 2. Anisotropy = 0.7.
- .. figure:: /images/render_shader-nodes_textures_gabor_example-phase-isotropic.jpg
:width: 320px
Phase output. Frequency = 2. Anisotropy = 0.7.
- .. figure:: /images/render_shader-nodes_textures_gabor_example-intensity-isotropic.jpg
:width: 320px
Intensity output. Frequency = 2. Anisotropy = 0.7.
Gabor noise is decomposed into a *Phase* and an *Intensity* components, where the Gabor value is
computed as sine the phase multiplied by the intensity, noting that the phase output is normalized
to the [0, 1] range.
.. figure:: /images/render_shader-nodes_textures_gabor_example-value-from-phase-intensity.png
Compute the value output from the phase and intensity outputs.
The advantage of the *Phase* output is that it has no random intensities and no low contrast areas
as in the value output, so it can be used as a base for textures that are more structured in nature,
like sand dunes.
.. figure:: /images/render_shader-nodes_textures_gabor_example-sand.png
Sand dune-like structures creates using the phase output.
The main advantage and use of the *Intensity* output is that it provides information about the
location of *singularities* in the *Phase* output. Singularities are those areas in the phase where
the bands meet, which are shown in red in the following figure. Those areas will be close to zero in
the *Intensity* output. So if those areas are undesirable, they can be hidden by multiplying by a
variant of the *Intensity* output.
.. figure:: /images/render_shader-nodes_textures_gabor_example-singularities.png
Visualization of the areas where singularities happen.
Inputs can be varies across space to get more interesting patterns.
.. figure:: /images/render_shader-nodes_textures_gabor_example-variable-inputs.png
Varying the frequency and orientation across space.
|
