1.5.6
#include <MVaryingParameter.h>
The MVaryingParameter class provides a high-level interface to hardware shader varying parameters. By defining your shader's varying data through this class, you allow Maya to handle the attributes, editing, serialisation, requirements setup, and cache management for you in a standard way that ensure you'll be able to leverage future performance and functionlity improvements.
At setup time (either initial load or when the effect/technique is changed), your shader simply creates the list of parameters it requires, specifying the name, type, semantic of the parameters. At render time, you can then use the parameters to directly access the appropriate buffers for that surface data.
If you include a custom Attribute Editor template for your shader node, you can include these surface parameters by calling the AEhwShaderTemplateParameters script function. The following sample code provides a basic template you can modify - however your AE template can use as much or as little of this as you like:
global int $yourShaderNameTemplateInitialised = 0; global proc AEyourShaderNameTemplate ( string $node ) { global int $yourShaderNameTemplateInitialised; if( $yourShaderNameTemplateInitialised == 0) { source "AEhwShaderTemplate.mel"; $yourShaderNameTemplateInitialised = 1; } AEhwShaderTemplateHeader( $node); // Insert custom attributes between the swatch and the parameters here AEhwShaderTemplateParameters( $node); // Insert custom attributes after the parameters here AEhwShaderTemplateFooter( $node); }
hlslShader.cpp, and hlslShader.h.
| MVaryingParameter::MVaryingParameter | ( | ) |
Create an uninitialised (i.e. NULL) geometry parameter.
| MVaryingParameter::MVaryingParameter | ( | const MString & | name, | |
| MVaryingParameterType | type, | |||
| int | minElements = 1, |
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| int | maxElements = 1, |
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| MVaryingParameterSemantic | semantic = kNoSemantic, |
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| bool | invertTexCoords = false | |||
| ) |
Create a new geometry parameter.
| [in] | name | the name of the new parameter. For independently configurable inputs, this must be unique across all parameters on the shader. If multiple parameters share the same name, only a single input will be presented to the user, and the value used to populate the set of commonly named parameters. |
| [in] | type | the type of the new parameter. This can either be an atomic type (e.g. float), or a structure containing other parameters. Vectors of atomic types (e.g. float4) are defined by setting the atomic type to kFloat, and specifying the maxElements value of 4. |
| [in] | minElements | specifies the minimum number of elements of the specified atomic type that should be used to populate this parameter. Many hardware channels allow binding of a variable number of elements per value; for example you can bind a stream of float3s or float4s to a color register. In this case, you would specify a minElements value of 3, and a maxElements value of 4. This value is ignored for structures and elements inside structures (elements inside a structure are always maxElements size). |
| [in] | maxElements | specifies the maximum number of elements of the specified atomic type that should be used to populate this parameter. See minElements for more information. This value is ignored for structures. |
| [in] | semantic | specifies the expected usage of the paramter (e.g. we expect this to be a colour, or a tangent, etc). This gives Maya a hint as to how the input should be presented to the user, and possibly even which input data is valid for this parameter. This value is ignored for structures. |
| MVaryingParameter::~MVaryingParameter | ( | ) |
Class destructor.
| const MVaryingParameter & MVaryingParameter::operator= | ( | const MVaryingParameter & | src | ) |
Assignment operator
| const MString & MVaryingParameter::name | ( | ) | const |
| MVaryingParameter::MVaryingParameterType MVaryingParameter::type | ( | ) | const |
Get the type of this parameter
| MVaryingParameter::MVaryingParameterSemantic MVaryingParameter::semantic | ( | ) | const |
| MStatus MVaryingParameter::getBuffer | ( | MGeometry & | geometry, | |
| const void *& | data, | |||
| unsigned int & | elements, | |||
| unsigned int & | count | |||
| ) | const |
Get the data for this parameter as a system memory buffer.
| [in] | geometry | the geometry cache the data should be retrieved from. This corresponds to the shape (e.g. mesh) you want the data for. |
| [out] | data | returns a pointer to the data (or NULL if the parameter is not available). |
| [in] | elements | the number of elements specified for this parameter (e.g. is it 3 floats or 4 floats?) |
| [in] | count | the number of values returned for this parameter (e.g. there are 426 normals) |
| MVaryingParameter::MVaryingParameterSemantic MVaryingParameter::getSourceType | ( | ) | const |
Get the type of data (e.g. position, normal, uv) currently populating this parameter. This method will only return a useful value when called on leaf-level parameters (e.g. structures do not have sources, only the elements of a structure have sources).
| MString MVaryingParameter::getSourceSetName | ( | ) | const |
If the current data type supports data sets (e.g. uv sets, color sets), get the name of the data set populating this parameter. This method will only return a useful value when called on leaf-level parameters (e.g. structures do not have sources, only the elements of a structure have sources).
| MStatus MVaryingParameter::setSource | ( | MVaryingParameter::MVaryingParameterSemantic | type, | |
| const MString & | setName | |||
| ) |
While the source of geometry parameters is usually configured by the artist through Maya's user interface, this method allows you to programatically set the source of a geometry parameter, including both the data type (e.g. position, normal, etc) and an optional set name (e.g. UV set "map1"). This is useful for implementing custom default values or shader operations.
| [in] | type | the type of data to populate this parameter with |
| [in] | setName | the specific data set to use for parameter types which support data sets, such as UV and color. |
| unsigned int MVaryingParameter::getElementSize | ( | ) | const |
Get the size in bytes of one element of this parameter.
| unsigned int MVaryingParameter::getMaximumStride | ( | ) | const |
Get the maximum stride of this parameter in bytes. For parameter that accept a range of element counts, this corresponds to the maximum number of elements the parameter supports.
| MStatus MVaryingParameter::addElement | ( | const MVaryingParameter & | child | ) |
Add a child element to this parameter. This operation is only valid for parameters of type kStructure.
| [in] | child | the parameter to add to the structure. |
| unsigned int MVaryingParameter::numElements | ( | ) | const |
Get the number of elements in this structure. This operation is only valid for parameters of type kStructure.
| MVaryingParameter MVaryingParameter::getElement | ( | unsigned int | i | ) | const |
Get an element within a structure. This operation is only valid for parameters of type kStructure.
| [in] | i | The index of the structure element to return. |
| MStatus MVaryingParameter::removeElements | ( | ) |
Remove all child elements from a structure. This operation is only valid for parameters of type kStructure.
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