attributeSpec.h

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//
// Copyright 2016 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_USD_SDF_ATTRIBUTE_SPEC_H
#define PXR_USD_SDF_ATTRIBUTE_SPEC_H

/// \file sdf/attributeSpec.h

#include "pxr/pxr.h"
#include "pxr/usd/sdf/api.h"
#include "pxr/usd/sdf/declareSpec.h"
#include "pxr/usd/sdf/path.h"
#include "pxr/usd/sdf/propertySpec.h"
#include "pxr/usd/sdf/types.h"
#include "pxr/base/tf/enum.h"

PXR_NAMESPACE_OPEN_SCOPE

/// \class SdfAttributeSpec
///
/// A subclass of SdfPropertySpec that holds typed data.
///
/// Attributes are typed data containers that can optionally hold any
/// and all of the following:
/// \li A single default value.
/// \li An array of knot values describing how the value varies over time.
/// \li A dictionary of posed values, indexed by name.
///
/// The values contained in an attribute must all be of the same type.  In the
/// Python API the \c typeName property holds the attribute type.  In the C++
/// API, you can get the attribute type using the GetTypeName() method.  In
/// addition, all values, including all knot values, must be the same shape.
/// For information on shapes, see the VtShape class reference in the C++
/// documentation.
///
class SdfAttributeSpec : public SdfPropertySpec
{
    SDF_DECLARE_SPEC(SdfAttributeSpec, SdfPropertySpec);

public:
    typedef SdfAttributeSpec This;
    typedef SdfPropertySpec Parent;

    ///
    /// \name Spec construction
    /// @{

    /// Constructs a new prim attribute instance.
    ///
    /// Creates and returns a new attribute for the given prim.
    /// The \p owner will own the newly created attribute.
    SDF_API
    static SdfAttributeSpecHandle
    New(const SdfPrimSpecHandle& owner,
        const std::string& name, const SdfValueTypeName& typeName,
        SdfVariability variability = SdfVariabilityVarying,
        bool custom = false);

    /// @}

    /// \name Connections
    /// @{

    /// Returns a proxy for editing the attribute's connection paths.
    ///
    /// The returned proxy, which is an SdfListEditorProxy, modifies the
    /// SdfListOp that represents this attribute's connections.
    SDF_API
    SdfConnectionsProxy GetConnectionPathList() const;

    /// Returns \c true if any connection paths are set on this attribute.
    SDF_API
    bool HasConnectionPaths() const;

    /// Clears the connection paths for this attribute.
    SDF_API
    void ClearConnectionPaths();

    /// @}
    /// \name Attribute value API
    /// @{

    /// Returns the allowed tokens metadata for this attribute.
    /// Consumers may use this metadata to define a set of predefined
    /// options for this attribute's value. However, this metadata is
    /// purely advisory. It is up to the consumer to perform any
    /// validation against this set of tokens, if desired.
    SDF_API
    VtTokenArray GetAllowedTokens() const;

    /// Sets the allowed tokens metadata for this attribute.
    SDF_API
    void SetAllowedTokens(const VtTokenArray& allowedTokens);

    /// Returns true if allowed tokens metadata is set for this attribute.
    SDF_API
    bool HasAllowedTokens() const;

    /// Clears the allowed tokens metadata for this attribute.
    SDF_API
    void ClearAllowedTokens(); 

    /// Returns the display unit of the attribute.
    SDF_API
    TfEnum GetDisplayUnit() const;

    /// Sets the display unit of the attribute.
    SDF_API
    void SetDisplayUnit(const TfEnum& displayUnit);

    /// Returns true if a display unit is set for this attribute.
    SDF_API
    bool HasDisplayUnit() const;

    /// Clears the display unit of the attribute.
    SDF_API
    void ClearDisplayUnit();

    /// Returns the color space in which a color or texture valued attribute 
    /// is authored. Refer to GfColorSpaceNames for the list of built in
    /// color spaces.
    SDF_API
    TfToken GetColorSpace() const;

    /// Sets the color space in which a color or texture valued attribute is 
    /// authored.
    SDF_API
    void SetColorSpace(const TfToken &colorSpace);

    /// Returns true if this attribute has a colorSpace value authored.
    SDF_API
    bool HasColorSpace() const;

    /// Clears the colorSpace metadata value set on this attribute.
    SDF_API
    void ClearColorSpace();
    
    /// @}
    /// \name Spec properties
    /// @{

    /// Returns the roleName for this attribute's typeName.
    ///
    /// If the typeName has no roleName, return empty token.
    SDF_API
    TfToken GetRoleName() const;

    /// @}

    /// \name Time-sample API
    /// @{
    /// Returns the entire set of time samples.
    SDF_API
    SdfTimeSampleMap GetTimeSampleMap() const;

    SDF_API
    std::set<double> ListTimeSamples() const;

    SDF_API
    size_t GetNumTimeSamples() const;

    SDF_API
    bool GetBracketingTimeSamples(double time, double* tLower,
                                  double* tUpper) const;

    SDF_API
    bool QueryTimeSample(double time, VtValue *value=NULL) const;
    SDF_API
    bool QueryTimeSample(double time, SdfAbstractDataValue *value) const;

    template <class T>
    bool QueryTimeSample(double time, T* data) const
    {
        if (!data) {
            return QueryTimeSample(time);
        }

        SdfAbstractDataTypedValue<T> outValue(data);
        const bool hasValue = QueryTimeSample(
            time, static_cast<SdfAbstractDataValue *>(&outValue));

        if (std::is_same<T, SdfValueBlock>::value) {
            return hasValue && outValue.isValueBlock;
        }

        return hasValue && (!outValue.isValueBlock);
    }

    SDF_API
    void SetTimeSample(double time, const VtValue & value);
    SDF_API
    void SetTimeSample(double time, const SdfAbstractDataConstValue& value);

    template <class T>
    void SetTimeSample(double time, const T& value)
    {
        const SdfAbstractDataConstTypedValue<T> inValue(&value);
        const SdfAbstractDataConstValue& untypedInValue = inValue;
        return SetTimeSample(time, untypedInValue);
    }

    SDF_API
    void EraseTimeSample(double time);

    /// @}
};

/// Convenience function to create an attributeSpec on a primSpec at the given
/// path, and any necessary parent primSpecs, in the given layer.
///
/// If an attributeSpec already exists at the given path,
/// author typeName, variability, and custom according to passed arguments
/// and return an attribute spec handle.
///
/// Any newly created prim specs have SdfSpecifierOver and an empty type (as if
/// created by SdfJustCreatePrimInLayer()).  attrPath must be a valid prim
/// property path (see SdfPath::IsPrimPropertyPath()).  Return false and issue
/// an error if we fail to author the required scene description.
SDF_API
SdfAttributeSpecHandle
SdfCreatePrimAttributeInLayer(
    const SdfLayerHandle &layer,
    const SdfPath &attrPath,
    const SdfValueTypeName &typeName,
    SdfVariability variability = SdfVariabilityVarying,
    bool isCustom = false);

/// Convenience function to create an attributeSpec on a primSpec at the given
/// path, and any necessary parent primSpecs, in the given layer.
///
/// If an attributeSpec already exists at the given path, just author typeName,
/// variability, and custom according to passed arguments and return true.
///
/// Any newly created prim specs have SdfSpecifierOver and an empty type (as if
/// created by SdfJustCreatePrimInLayer()).  attrPath must be a valid prim
/// property path (see SdfPath::IsPrimPropertyPath()).  Return false and issue
/// an error if we fail to author the required scene description.
///
/// Differs only from SdfCreatePrimAttributeInLayer only in that a bool, not
/// a handle, is returned.
SDF_API
bool
SdfJustCreatePrimAttributeInLayer(
    const SdfLayerHandle &layer,
    const SdfPath &attrPath,
    const SdfValueTypeName &typeName,
    SdfVariability variability = SdfVariabilityVarying,
    bool isCustom = false);

PXR_NAMESPACE_CLOSE_SCOPE

#endif // PXR_USD_SDF_ATTRIBUTE_SPEC_H