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Shader MetadataThe metadata about the shader itself is provided between the shader name and its parameter list. For instance:
The supported shader annotations are:
Specifies the string to use for the shader name in the user interface, when possible.
Katana-specific An array of n strings defining tags for the shader. The supported tags are:
Maya-specific Specifies the type ID used for the node registration. This is a integer that Maya uses to identify the node type, most notably when saving a scene in the Maya Binary format. Each OSL shader that defines a given shading node type should be assigned a unique type ID. You can chose a value between The IDs from You may use any ID between
Maya-specific Specifies the Maya shading node classification. The classification affects where the node is presented in the Hypershade tree lister and menus. Some classification types will also change the node creation mechanism to automatically create and connect related nodes - for instance, creating a surface shader will also create and connect a shading group. The classification string will be prepended with the standard 3Delight shader node classification string so that the nodes are correctly identified as supported shading nodes when the scene is output to the renderer. The classification string can be set to any value, but using one of the following will list the shader in the specified 3Delight category in the HyperShade:
The shading node will be classified as a surface shader and will be listed under 3Delight → Surface in the HyperShade. Upon creation, Maya will create a new shading group and connect this surface shader' |
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s |
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attribute to it. The shader must provide an output color closure parameter that is either |
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named |
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or mapped to that attribute name using the
The shading node will be classified as |
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a 2D Texture node and will be listed under 3Delight → 2D Textures in the HypersShade. Upon creation, Maya will automatically create and connect |
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a place2DTexture |
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node to the shader's uvCoord parameter. See UV Coordinate parameter below for details on how to declare such parameter.
The shading node will be classified as a 3D Texture node and will be listed under 3Delight → 3D Textures in the HypersShade. Upon creation, Maya will automatically create and connect a place3DTexture node to the shader's placementMatrix attribute. The OSL shader must provide a matrix input parameter that is either |
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named |
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or mapped to |
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the |
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attribute name using |
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the |
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or |
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metadata.
The shading node will be classified as |
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a Utility |
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node and will be listed under 3Delight → Utilities.
Maya-specific Setting this to 0 allows providing a complete custom template using a MEL file, just like any other node. Setting this metadata to 1 (or not specifying it at all) will have 3Delight for Maya |
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generate an Attribute Editor template automatically based on the shader parameters' metadata. Parameter metadataParameter metadata is provided between a parameter's default value and the comma that ends its declaration. For instance:
The supported parameter annotations are:
Specifies the name of the attribute that corresponds to this parameter. There are many reasons to use these attribute - parameter mapping: because the software or OSL imposes restrictions (e.g. an attribute named "color" |
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in Maya, which is a reserved word in OSL), because the shader has different parameter naming conventions than what is expected in the software, or because the required attribute in the software is part of a complex attribute structure that does not have an OSL counterpart.
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is Maya-specific and |
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overrides |
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is Katana-specific and |
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overrides When none of the above metadata are provided, the parameter name is used directly to define the attribute name.
Specifies the label of the widget that controls the attribute.
Specifies the minimum and maximum values allowed for the attribute. |
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In Katana, this defines the slider range, as an attribute value cannot be bounded.
Maya-specific Specifies the attribute name to use in the user interface, when possible. This will be used in |
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the Maya |
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editors, notably |
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the Node Editor |
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and the Channel Box. It will also be used for the automatically |
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generated Attribute Editor |
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template, |
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unless |
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is specified.
This metadata provides extra options for specific widget types. |
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See |
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for details.
Defines the name of a group under which the widget of the attribute will be placed. Nested groups can be defined by formatting |
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the |
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value string |
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as
Specifies the range of of the slider widget that controls the attribute. This is ignored in Katana.
Specifies the type of the attribute related to this shader parameter. By default, the attribute type is derived from the parameter type and the widget type.
Valid for integer shader parameters.
Valid for integer shader parameters. The enumeration list should be set using the options metadata.
Maya-specific Valid for string shader parameters. A message attribute will be created and the connected node's name will be passed as this shader parameter's value.
Defines the type of widget to control the attribute's value.
A check box widget. Implies a boolean attribute type.
A combination of widgets suitable for a filename. This usually consists of a text field and a file browser button, with some extra features depending of the host software.
An option menu with a list of items that have an associated numeric value. The list of item labels and values are defined using the |
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the |
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metadata. The expected format is a list of labels, optionally with values, separated by |
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a
A combination of widgets suitable to handle a connection from another node.
No widget will be created for this attribute.
An option menu. The selected menu item label is set as the attribute value. This widget works for string shader parameters. The menu items are defined by |
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the |
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metadata as a list of labels separated |
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by
The ramp widgets require more than one shader parameters and are explained in a dedicated section. Getting the texture coordinates Because retrieving the UV coordinates is a costly process, it is best to centralize this operation in a single shader and share the results with all shaders. For a shader to benefit of this, it may declare a parameter similar to this:
This uses the following metadata intended to address this specific problem:
This combination of metadata instruct that when no incoming connection exists on the node attribute, one should be established between the uvCoord shader that 3Delight outputs by default and this parameter. The uvCoord shader is the centralized place to fetch the UV coordinates. Ramp widgetsThe ramp widgets in Maya and Katana both require 3 different attributes. They also have diverging expectations and features. Maya-style float ramp widgetThe triplet of shader parameters required to present a Maya-style float ramp can be declared as follows:
Maya-style color ramp widget
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