This node specifies the current pattern for all subsequent shape nodes in a scene graph.

A pattern is a 32x32 bitmap that is interpreted as a mask of 0s and 1s. Where a 1 appears, the corresponding pixel in the polygon is drawn; where a 0 appears, nothing is drawn. Using patterns is like using screendoor transparency where you specify the pattern of the screen. OpenGL polygon stippling is used to render the pattern.

You can load a pattern file containing one or more patterns using the loadPatterns() method. You can also define and load patterns programmatically using the addPattern() method.

Here is a sample showing the pattern file format.

  "GEOLOGY"
 # The first string is the category name of the first pattern.
 # This is a comment !
 "PATTERN N1"
 # The second string is the name of the pattern.
 # To define the pattern, you must define a 32x32 sequence of
 # '1' and '0'.
 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 ...
 #============================================
 "PATTERN N2"
 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 ...

• A pattern file can contain only one category.

• There is a potential conflict between the use of screendoor transparency and patterned shapes. If the transparency type is screendoor, transparency is ignored for patterned shapes.

Usage Notes

• Patterns can be used for distinguishing, for example, different kinds of rocks in a geologic formation.

• The HardCopy extension (formerly known as PlotMaster) allows you to generate resolution-independent vector hardcopy output. It handles patterns but does not handle textures (they are ignored). If you are planning to use the HardCopy extension, you may want to use patterns rather than textures to distinguish different shapes in your scene graph.

FILE FORMAT/DEFAULT

Pattern {

category	""
name	""

}

NOTE: When you write a pattern node out to a file, the file will not contain enough information to fully reconstruct the original scene graph. The pattern node and its current fields are written out (as expected). However, the current fields only specify a category name and a pattern name. They do not specify the actual pattern(s) (like a typical attribute node) or a filename to get the patterns from (like a texture node).

Reference