final class ShaderParameter<T>

TODO: Document GLSL Shaders

A ShaderParameter instance represents a single input parameter of a shader kernel. A kernel can be defined to accept zero, one, or more parameters that are used in the kernel execution. A ShaderParameter provides information about the parameter, such as the type of data it expects. It also provides a mechanism for setting the parameter value that is used when the shader executes. To specify a value or values for the shader parameter, create an Array containing the value or values and assign it to the value property.

A ShaderParameter instance representing a parameter for a Shader instance is accessed as a property of the Shader instance's data property. The ShaderParameter property has the same name as the parameter's name in the shader code. For example, if a shader defines a parameter named radius, the ShaderParameter instance representing the radius parameter is available as the radius property, as shown here:

var radiusParam:ShaderParameter = myShader.data.radius;

In addition to the defined properties of the ShaderParameter class, each ShaderParameter instance has additional properties corresponding to any metadata defined for the parameter. These properties are added to the ShaderParameter object when it is created. The properties' names match the metadata names specified in the shader's source code. The data type of each property varies according to the data type of the corresponding metadata. A text metadata value such as "description" is a String instance. A metadata property with a non-string value (such as minValue or defaultValue) is represented as an Array instance. The number of elements and element data types correspond to the metadata values.

For example, suppose a shader includes the following two parameter declarations:

parameter float2 size
<
	description: "The size of the image to which the kernel is applied";
	minValue: float2(0.0, 0.0);
	maxValue: float2(100.0, 100.0);
	defaultValue: float2(50.0, 50.0);
>;

parameter float radius
<
	description: "The radius of the effect";
	minValue: 0.0;
	maxValue: 50.0;
	defaultValue: 25.0;
>;

The ShaderParameter instance corresponding to the size parameter has the following metadata properties in addition to its built-in properties:

Property name	Data type	Value
name	String	"size"
description	String	"The size of the image to which the kernel is applied"
minValue	Array	[0, 0]
maxValue	Array	[100, 100]
defaultValue	Array	[50, 50]

The ShaderParameter corresponding to the radius parameter has the following additional properties:

Property name	Data type	Value
name	String	"radius"
description	String	"The radius of the effect"
minValue	Array	[0]
maxValue	Array	[50]
defaultValue	Array	[25]

Generally, developer code does not create a ShaderParameter instance directly. A ShaderParameter instance is created for each of a shader's parameters when the Shader instance is created.

myShader.data.myMatrix.value = [.1, .2, .3, .4];