This operator computes a filtered sample of the texture map specified and returns an RGB or RGBA color. If the image does not have an alpha channel (e.g. a JPEG image) and the operator returns RGBA, the alpha will be set to 1.
With no texture coordinates given, the values of the global s and t
variables are used to index the texture. If both derivative inputs (ds
and dt) are connected,
t will represent the center of a square
whose bottom-left and upper-right corners are (s-ds,t-dt) and (s+ds,
t+dt) respectively .
To layer a texture on top of another using layered texture attributes already assigned to geometry, pipe the output of the Shading Layer Parameter into Vector To Float, then connect fval1 and fval2 to this operator’s s and t inputs, choosing the RGBA signature and Decal wrapping. Then connect the color output to a Vector4 To Vector operator to separate the RGB from the alpha. Put down a Mix operator and connect the RGB color to input2, the alpha to the bias and any previous Texture’s color to input1. Repeat this procedure as needed.
RGB or RGBA values
The image file to use as a texture map.
UDIM Filename Expansion
UDIM texture filename expansion.
The UDIM coordinate is computed based on the uv-coordinate:
1000 + int(u)+1 + int(v)*10.
Example: “map_%(UDIM)d.rat” returns “map_1044.rat” with u=3.1, v=4.15
Source Color Space
The texture’s color space.
S coordinate (or global
T coordinate (or global
Derivative with respect to s (see UV Project)
Derivative with respect to t (see UV Project)
Determines how the image is evaluated when the texture coordinates are outside the range 0-1. The options are:
repeat). The image map repeats outside the
range 0 to 1. Basically, the integer component of the texture
coordinate is ignored.
streak). Texture coordinates are clamped to
the 0 to 1 range.
decal). Coordinates outside the range 0 to 1
will evaluate to the border color rather than an image
Type of anti-aliasing filter to be used for evaluation. The options are:
Blur the texture based on derivatives in shading contexts. For contexts that do not provide derivatives (such as the sop context), this parameter will have no effect and you should use Texture Blur or Pixel Blur instead. In shading contexts, filtering will be proportional to the micropolygon size with a filter width of 1, filtering one micropolygon.
Blur the texture as a percentage of the image width. The blur is specified as 0 (no blur) to 1 (blur the entire image).
Blur the texture by the specified number of pixels. If the resolution of the map changes, the amount of blur will change.
Border color when Decal wrapping is used.
Specifies whether derivative extrapolation should be used when computing anti-aliasing information.
Interpolate MIP Levels
Specifies whether RAT files should interpolate between different MIP levels. If enabled, it will help remove discontinuities when different MIP levels of a RAT file are accessed. However, the results of texture evaluation will be slightly softer (i.e. blurrier) and will take twice as long to compute.
When evaluating decal textures, this is the color evaluated when outside of the decal.
This specifies which color channel for multi-plane textures should be evaluated.
When evaluating ptex files, the polygon face used to index into the map. This will default to the polygon number.
Sometimes texture maps (notably ptex textures) have different orientations than might be normal in Houdini. This parameter allows you to perform simple manipulations on the
t coordinates. The operations are:
Use the default
s coordinate (horizontal flip).
t coordinate (vertical flip).
t coordinates (diagonal flip).
When performing any operations, the flipping occurs before the swapping.