Function Pattern Types
The functional pattern types influence the reflectance of a
material according to a defined function.
There is a colored and an achromatic version.
Colorfunc
A colorfunc is a procedurally defined color pattern.
The values of the red, green, and blue modifier expressions
are multiplied with the material color values.
![[dialog]](images/colorfuncdef.gif)
Function File:
This pop-up list offers all function files known to the
system for selection. If a file is active, then the
variables in that file can be selected for one or several
of the vector coordinates. Otherwise, the coordinates
must be entered as expressions.
Edit...
Start the text editor that was configured in the project
preferences to edit the function file.
New...
Create a new function file, and start the text editor
to edit it.
Modification Red/Green/Blue:
The values that modify the color of the base material. Those
can either be selected from the variables in a function file
as selected above, or they may be entered as
expressions.
An expression can contain numeric values, operators
and all functions and variables known to the material.
If an expression is not valid, then the entry field
will have a red background, and the message bar at the
bottom of the dialog will show a diagnostic message.
Real Arguments
Rayfront will check the selected function file to
decide how many real arguments the material definition
should supply. If this number is greater than the
mandatory arguments specifying the basic properties,
then the expected number of entry fields in the list
is made available. Supplying those arguments is
optional, but failing to do so may result in runtime
errors when the selected function relies on a specific
argument which is not set.
The Transformation page
of the dialog can be used
to transform the vector, possibly to bring it in alignment
with the geometry of the surface the pattern modifies.
Brightfunc
A brightfunc is a procedurally defined monochromatic
reflectance pattern.
The value of the modifier expression is multiplied with
each of the material color values.
![[dialog]](images/brightfuncdef.gif)
Function File:
This pop-up list offers all function files known to the
system for selection. If a file is active, then the
variables in that file can be selected for one or several
of the vector coordinates. Otherwise, the coordinates
must be entered as expressions.
Edit...
Start the text editor that was configured in the project
preferences to edit the function file.
New...
Create a new function file, and start the text editor
to edit it.
Reflectance Modifier
The value that modifies the reflectance of the base material.
This can either be selected from the variables in a function
file as selected above, or it may be entered as an
expression.
An expression can contain numeric values, operators
and all functions and variables known to the material.
If an expression is not valid, then the entry field
will have a red background, and the message bar at the
bottom of the dialog will show a diagnostic message.
Real Arguments
Rayfront will check the selected function file to
decide how many real arguments the material definition
should supply. If this number is greater than the
mandatory arguments specifying the basic properties,
then the expected number of entry fields in the list
is made available. Supplying those arguments is
optional, but failing to do so may result in runtime
errors when the selected function relies on a specific
argument which is not set.
The Transformation page
of the dialog can be used
to transform the vector, possibly to bring it in alignment
with the geometry of the surface the pattern modifies.
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