The OSL texture node is a scriptable node that lets you write scripts using the OSL (Open Shader LanguageA shading language developed by Sony Pictures Imageworks. There are multiple render engines that utilize OSL as it is particularly suited for physically-based renderers.) standard programming language to define arbitrary Texture types to create customized MaterialsA set of attributes or parameters that describe surface characteristics. and shaders. OSL is a standard created by Sony Imageworks. To learn about the generic OSL standard, please read the OSL Readme and PDF documentation.
Figure 1: The OSL Texture node
There are two options to add scripts for the OSL texture. The Internal option is available by opening another area in Blender® for the Text Editor, creating a new text, and writing the OSL script. The External option lets you to select a pre-coded OSL file from the File Explorer window.