This chapter provides a general overview of SPDL files (commonly called SPDLs for short) used for shaders. SPDLs are ASCII-based files that contain important definition information about an object within Softimage. They are used extensively to define internal objects, for example each different type of operator and primitive available in the product has its own SPDL file.
SPDL files are also used for defining both native and custom shaders. The SPDL file does not include the complete implementation of an object, but it includes important information including the list of parameters on the object and the definition of the property page appearance.
The Shader Wizard automatically creates SPDLs for shaders.
|
Historically, SPDLs were used to build custom operators and standalone properties, but this practice has been deprecated in favor of the new APIs which create self-installing operators and properties. However, if you are developing custom shaders, you still need to use SPDL-based property pages. |
Parameters on a property page can contain numbers (integers and floats), text, and booleans. These parameters define the state of the object, and normally these values are exposed to the user on the object's property page. The value of each parameter is displayed using a UI widget (also called "input field" and "windows control") and the widget used depends on the parameter type. Each of these is contained in an input field specific to its type. Booleans, which represent properties that are true or false, are represented by radio buttons.
You can, however, change some of the default controls for these parameters. For example, you can add combo boxes with lists of options in them or color widgets that let users set the color and alpha of an object. For more details, see Dissecting the Sections of the Shader SPDL File.
The layout options allow you to group properties together and create tabs. For more information, see Defining Layout with SPDL.
You can write script code that contains subroutines to react to events in the property page. For more information, see Defining Property Page Logic with SPDL.
Calling Help from your SPDL Files
You can call .hlp or HTML files directly from your SPDL. This is enabled by the HelpFile parameter.
Example: Jump to a web site from the ? button
To call www.softimage.com from the ? button in a property page, specify the following line in the SPDL file:
HelpFile = "http://www.softimage.com"/;
Although you can use a text editor to create a SPDL file, you’ll find it much easier to use the shader wizard to create this file for you. When you use the shader wizard to create a shader, the wizard automatically creates the associated SPDL file.
• For more information on creating mental ray shader SPDLs, see Using the Shader Wizard.
• For more information on creating realtime shader SPDLs, see Generate the SPDL file.
Autodesk Softimage v7.5