| The ShaderAttributeSet object provides uniform attributes to shader
programs. Uniform attributes (variables) are those attributes whose
values are constant during the rendering of a primitive. Their
values may change from primitive to primitive, but are constant for
each vertex (for vertex shaders) or fragment (for fragment shaders)
of a single primitive. Examples of uniform attributes include a
transformation matrix, a texture map, lights, lookup tables, etc.
The ShaderAttributeSet object contains a set of ShaderAttribute
objects. Each ShaderAttribute object defines the value of a single
uniform shader variable. The set of attributes is unique with respect
to attribute names: no two attributes in the set will have the same
name.
There are two ways in which values can be specified for uniform
attributes: explicitly, by providing a value; and implicitly, by
defining a binding between a Java 3D system attribute and a uniform
attribute. This functionality is provided by two subclasses of
ShaderAttribute: ShaderAttributeObject, which is used to specify
explicitly defined attributes; and ShaderAttributeBinding, which is
used to specify implicitly defined, automatically tracked attributes.
Depending on the shading language (and profile) being used, several
Java 3D state attributes are automatically made available to the
shader program as pre-defined uniform attributes. The application
doesn't need to do anything to pass these attributes in to the
shader program. The implementation of each shader language (e.g.,
Cg, GLSL) defines its own bindings from Java 3D attribute to uniform
variable name. A list of these attributes for each shader language
can be found in the concrete subclass of ShaderProgram for that
shader language.
See Also: ShaderAttribute
See Also: ShaderProgram
See Also: ShaderAppearance.setShaderAttributeSet
since:
Java 3D 1.4 |
