subset.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 USDGEOM_GENERATED_SUBSET_H
#define USDGEOM_GENERATED_SUBSET_H

/// \file usdGeom/subset.h

#include "pxr/pxr.h"
#include "pxr/usd/usdGeom/api.h"
#include "pxr/usd/usd/typed.h"
#include "pxr/usd/usd/prim.h"
#include "pxr/usd/usd/stage.h"
#include "pxr/usd/usdGeom/tokens.h"

#include "pxr/base/tf/token.h"
#include "pxr/usd/usdGeom/imageable.h"
#include "pxr/usd/usdGeom/mesh.h"
#include "pxr/usd/usdGeom/tetMesh.h"
#include "pxr/usd/usdGeom/basisCurves.h"


#include "pxr/base/vt/value.h"

#include "pxr/base/gf/vec3d.h"
#include "pxr/base/gf/vec3f.h"
#include "pxr/base/gf/matrix4d.h"

#include "pxr/base/tf/token.h"
#include "pxr/base/tf/type.h"

PXR_NAMESPACE_OPEN_SCOPE

class SdfAssetPath;

// -------------------------------------------------------------------------- //
// GEOMSUBSET                                                                 //
// -------------------------------------------------------------------------- //

/// \class UsdGeomSubset
///
/// Encodes a subset of a piece of geometry (i.e. a UsdGeomImageable) 
/// as a set of indices. Currently supports encoding subsets of faces, 
/// points, edges, segments, and tetrahedrons.
/// 
/// To apply to a geometric prim, a GeomSubset prim must be the prim's direct 
/// child in namespace, and possess a concrete defining specifier (i.e. def). 
/// This restriction makes it easy and efficient to discover subsets of a prim. 
/// We might want to relax this restriction if it's common to have multiple 
/// <b>families</b> of subsets on a gprim and if it's useful to be able to 
/// organize subsets belonging to a <b>family</b> under a common scope. See 
/// 'familyName' attribute for more info on defining a family of subsets.
/// 
/// Note that a GeomSubset isn't an imageable (i.e. doesn't derive from
/// UsdGeomImageable). So, you can't author <b>visibility</b> for it or 
/// override its <b>purpose</b>.
/// 
/// Materials are bound to GeomSubsets just as they are for regular 
/// geometry using API available in UsdShade (UsdShadeMaterial::Bind).
/// 
///
/// For any described attribute \em Fallback \em Value or \em Allowed \em Values below
/// that are text/tokens, the actual token is published and defined in \ref UsdGeomTokens.
/// So to set an attribute to the value "rightHanded", use UsdGeomTokens->rightHanded
/// as the value.
///
class UsdGeomSubset : public UsdTyped
{
public:
    /// Compile time constant representing what kind of schema this class is.
    ///
    /// \sa UsdSchemaKind
    static const UsdSchemaKind schemaKind = UsdSchemaKind::ConcreteTyped;

    /// Construct a UsdGeomSubset on UsdPrim \p prim .
    /// Equivalent to UsdGeomSubset::Get(prim.GetStage(), prim.GetPath())
    /// for a \em valid \p prim, but will not immediately throw an error for
    /// an invalid \p prim
    explicit UsdGeomSubset(const UsdPrim& prim=UsdPrim())
        : UsdTyped(prim)
    {
    }

    /// Construct a UsdGeomSubset on the prim held by \p schemaObj .
    /// Should be preferred over UsdGeomSubset(schemaObj.GetPrim()),
    /// as it preserves SchemaBase state.
    explicit UsdGeomSubset(const UsdSchemaBase& schemaObj)
        : UsdTyped(schemaObj)
    {
    }

    /// Destructor.
    USDGEOM_API
    virtual ~UsdGeomSubset();

    /// Return a vector of names of all pre-declared attributes for this schema
    /// class and all its ancestor classes.  Does not include attributes that
    /// may be authored by custom/extended methods of the schemas involved.
    USDGEOM_API
    static const TfTokenVector &
    GetSchemaAttributeNames(bool includeInherited=true);

    /// Return a UsdGeomSubset holding the prim adhering to this
    /// schema at \p path on \p stage.  If no prim exists at \p path on
    /// \p stage, or if the prim at that path does not adhere to this schema,
    /// return an invalid schema object.  This is shorthand for the following:
    ///
    /// \code
    /// UsdGeomSubset(stage->GetPrimAtPath(path));
    /// \endcode
    ///
    USDGEOM_API
    static UsdGeomSubset
    Get(const UsdStagePtr &stage, const SdfPath &path);

    /// Attempt to ensure a \a UsdPrim adhering to this schema at \p path
    /// is defined (according to UsdPrim::IsDefined()) on this stage.
    ///
    /// If a prim adhering to this schema at \p path is already defined on this
    /// stage, return that prim.  Otherwise author an \a SdfPrimSpec with
    /// \a specifier == \a SdfSpecifierDef and this schema's prim type name for
    /// the prim at \p path at the current EditTarget.  Author \a SdfPrimSpec s
    /// with \p specifier == \a SdfSpecifierDef and empty typeName at the
    /// current EditTarget for any nonexistent, or existing but not \a Defined
    /// ancestors.
    ///
    /// The given \a path must be an absolute prim path that does not contain
    /// any variant selections.
    ///
    /// If it is impossible to author any of the necessary PrimSpecs, (for
    /// example, in case \a path cannot map to the current UsdEditTarget's
    /// namespace) issue an error and return an invalid \a UsdPrim.
    ///
    /// Note that this method may return a defined prim whose typeName does not
    /// specify this schema class, in case a stronger typeName opinion overrides
    /// the opinion at the current EditTarget.
    ///
    USDGEOM_API
    static UsdGeomSubset
    Define(const UsdStagePtr &stage, const SdfPath &path);

protected:
    /// Returns the kind of schema this class belongs to.
    ///
    /// \sa UsdSchemaKind
    USDGEOM_API
    UsdSchemaKind _GetSchemaKind() const override;

private:
    // needs to invoke _GetStaticTfType.
    friend class UsdSchemaRegistry;
    USDGEOM_API
    static const TfType &_GetStaticTfType();

    static bool _IsTypedSchema();

    // override SchemaBase virtuals.
    USDGEOM_API
    const TfType &_GetTfType() const override;

public:
    // --------------------------------------------------------------------- //
    // ELEMENTTYPE 
    // --------------------------------------------------------------------- //
    /// The type of element that the indices target. "elementType" can
    /// have one of the following values:
    /// <ul><li><b>face</b>: Identifies faces on a Gprim's surface. For a 
    /// UsdGeomMesh, each element of the _indices_ attribute would refer to 
    /// an element of the Mesh's _faceCounts_ attribute. For a UsdGeomTetMesh,
    /// each element of the _indices_ attribute would refer to an element of
    /// the Mesh's _surfaceFaceVertexIndices_ attribute.</li>
    /// <li><b>point</b>: for any UsdGeomPointBased, each 
    /// element of the _indices_ attribute would refer to an element of the 
    /// Mesh's _points_ attribute</li>
    /// <li><b>edge</b>: for any UsdGeomMesh, each pair of elements
    /// in the _indices_ attribute would refer to a pair of points of the 
    /// Mesh's _points_ attribute that are connected as an implicit edge on the 
    /// Mesh. These edges are derived from the Mesh's _faceVertexIndices_ 
    /// attribute. Edges are not currently defined for a UsdGeomTetMesh, but
    /// could be derived from all tetrahedron edges or surface face edges only 
    /// if a specific use-case arises.</li>
    /// <li><b>segment</b>: for any Curve, each pair of elements 
    /// in the _indices_ attribute would refer to a pair of indices 
    /// (_curveIndex_, _segmentIndex_) where _curveIndex_ is the position of 
    /// the specified curve in the Curve's _curveVertexCounts_ attribute, and 
    /// _segmentIndex_ is the index of the segment within that curve.</li>
    /// <li><b>tetrahedron</b>: for any UsdGeomTetMesh, each element of the 
    /// _indices_ attribute would refer to an element of the TetMesh's 
    /// _tetVertexIndices_ attribute.
    /// </li></ul>
    ///
    /// | ||
    /// | -- | -- |
    /// | Declaration | `uniform token elementType = "face"` |
    /// | C++ Type | TfToken |
    /// | \ref Usd_Datatypes "Usd Type" | SdfValueTypeNames->Token |
    /// | \ref SdfVariability "Variability" | SdfVariabilityUniform |
    /// | \ref UsdGeomTokens "Allowed Values" | face, point, edge, segment, tetrahedron |
    USDGEOM_API
    UsdAttribute GetElementTypeAttr() const;

    /// See GetElementTypeAttr(), and also 
    /// \ref Usd_Create_Or_Get_Property for when to use Get vs Create.
    /// If specified, author \p defaultValue as the attribute's default,
    /// sparsely (when it makes sense to do so) if \p writeSparsely is \c true -
    /// the default for \p writeSparsely is \c false.
    USDGEOM_API
    UsdAttribute CreateElementTypeAttr(VtValue const &defaultValue = VtValue(), bool writeSparsely=false) const;

public:
    // --------------------------------------------------------------------- //
    // INDICES 
    // --------------------------------------------------------------------- //
    /// The set of indices included in this subset. The indices need not 
    /// be sorted, but the same index should not appear more than once. Indices 
    /// are invalid if outside the range [0, elementCount) for the given time on 
    /// the parent geometric prim.
    ///
    /// | ||
    /// | -- | -- |
    /// | Declaration | `int[] indices = []` |
    /// | C++ Type | VtArray<int> |
    /// | \ref Usd_Datatypes "Usd Type" | SdfValueTypeNames->IntArray |
    USDGEOM_API
    UsdAttribute GetIndicesAttr() const;

    /// See GetIndicesAttr(), and also 
    /// \ref Usd_Create_Or_Get_Property for when to use Get vs Create.
    /// If specified, author \p defaultValue as the attribute's default,
    /// sparsely (when it makes sense to do so) if \p writeSparsely is \c true -
    /// the default for \p writeSparsely is \c false.
    USDGEOM_API
    UsdAttribute CreateIndicesAttr(VtValue const &defaultValue = VtValue(), bool writeSparsely=false) const;

public:
    // --------------------------------------------------------------------- //
    // FAMILYNAME 
    // --------------------------------------------------------------------- //
    /// The name of the family of subsets that this subset belongs to. 
    /// This is optional and is primarily useful when there are multiple 
    /// families of subsets under a geometric prim. In some cases, this could 
    /// also be used for achieving proper roundtripping of subset data between 
    /// DCC apps.
    /// When multiple subsets belonging to a prim have the same familyName, they 
    /// are said to belong to the family. A <i>familyType</i> value can be 
    /// encoded on the owner of a family of subsets as a token using the static 
    /// method UsdGeomSubset::SetFamilyType(). "familyType" can have one of the 
    /// following values:
    /// <ul><li><b>UsdGeomTokens->partition</b>: implies that every element of 
    /// the whole geometry appears exactly once in only one of the subsets
    /// belonging to the family.</li>
    /// <li><b>UsdGeomTokens->nonOverlapping</b>: an element that appears in one 
    /// subset may not appear in any other subset belonging to the family, and 
    /// appears only once in the subset in which it appears.</li>
    /// <li><b>UsdGeomTokens->unrestricted</b>: implies that there are no
    /// restrictions w.r.t. the membership of elements in the subsets. They 
    /// could be overlapping and the union of all subsets in the family may 
    /// not represent the whole.</li>
    /// </ul>
    /// \note The validity of subset data is not enforced by the authoring 
    /// APIs, however they can be checked using UsdGeomSubset::ValidateFamily().
    /// 
    ///
    /// | ||
    /// | -- | -- |
    /// | Declaration | `uniform token familyName = ""` |
    /// | C++ Type | TfToken |
    /// | \ref Usd_Datatypes "Usd Type" | SdfValueTypeNames->Token |
    /// | \ref SdfVariability "Variability" | SdfVariabilityUniform |
    USDGEOM_API
    UsdAttribute GetFamilyNameAttr() const;

    /// See GetFamilyNameAttr(), and also 
    /// \ref Usd_Create_Or_Get_Property for when to use Get vs Create.
    /// If specified, author \p defaultValue as the attribute's default,
    /// sparsely (when it makes sense to do so) if \p writeSparsely is \c true -
    /// the default for \p writeSparsely is \c false.
    USDGEOM_API
    UsdAttribute CreateFamilyNameAttr(VtValue const &defaultValue = VtValue(), bool writeSparsely=false) const;

public:
    // ===================================================================== //
    // Feel free to add custom code below this line, it will be preserved by 
    // the code generator. 
    //
    // Just remember to: 
    //  - Close the class declaration with }; 
    //  - Close the namespace with PXR_NAMESPACE_CLOSE_SCOPE
    //  - Close the include guard with #endif
    // ===================================================================== //
    // --(BEGIN CUSTOM CODE)--

    /// Creates a new GeomSubset below the given \p geom with the given 
    /// name, \p subsetName, element type, \p elementType and \p indices.
    /// 
    /// If a subset named \p subsetName already exists below \p geom, then 
    /// this updates its attributes with the values of the provided arguments 
    /// (indices value at time 'default' will be updated) and returns it. 
    /// 
    /// The family type is set / updated on \p geom only if a non-empty value 
    /// is passed in for \p familyType and \p familyName.
    USDGEOM_API
    static UsdGeomSubset CreateGeomSubset(
        const UsdGeomImageable &geom, 
        const TfToken &subsetName,
        const TfToken &elementType,
        const VtIntArray &indices,
        const TfToken &familyName=TfToken(),
        const TfToken &familyType=TfToken());

    /// Creates a new GeomSubset below the given imageable, \p geom with the 
    /// given name, \p subsetName, element type, \p elementType and \p indices.
    /// 
    /// If a subset named \p subsetName already exists below \p geom, then 
    /// this creates a new subset by appending a suitable index as suffix to 
    /// \p subsetName (eg, subsetName_1) to avoid name collisions.
    /// 
    /// The family type is set / updated on \p geom only if a non-empty value 
    /// is passed in for \p familyType and \p familyName.
    USDGEOM_API
    static UsdGeomSubset CreateUniqueGeomSubset(
        const UsdGeomImageable &geom, 
        const TfToken &subsetName,
        const TfToken &elementType,
        const VtIntArray &indices,
        const TfToken &familyName=TfToken(),
        const TfToken &familyType=TfToken());
    
    /// Returns all the GeomSubsets defined on the given imageable, \p geom. 
    USDGEOM_API
    static std::vector<UsdGeomSubset> GetAllGeomSubsets(
        const UsdGeomImageable &geom);

    /// Returns all the GeomSubsets of the given \p elementType belonging to 
    /// the specified family, \p familyName on the given imageable, \p geom.
    /// If \p elementType is empty, then subsets containing all element types 
    /// are returned.
    /// If \p familyName is left empty, then all subsets of the specified 
    /// \p elementType will be returned.
    USDGEOM_API
    static std::vector<UsdGeomSubset> GetGeomSubsets(
        const UsdGeomImageable &geom,
        const TfToken &elementType=TfToken(),
        const TfToken &familyName=TfToken());

    /// Returns the names of all the families of GeomSubsets defined on the given
    /// imageable, \p geom.
    USDGEOM_API
    static TfToken::Set GetAllGeomSubsetFamilyNames(
        const UsdGeomImageable &geom);

    /// This method is used to encode the type of family that the GeomSubsets 
    /// on the given geometric prim \p geom, with the given family name, 
    /// \p familyName belong to. 
    /// 
    /// See \ref UsdGeomSubset::GetFamilyNameAttr for the possible values for 
    /// \p familyType.
    /// 
    /// When a family of GeomSubsets is tagged as a UsdGeomTokens->partition or 
    /// UsdGeomTokens->nonOverlapping, the validity of the data (i.e. 
    /// mutual exclusivity and/or wholeness) is not enforced by the authoring 
    /// APIs. Use ValidateFamily() to validate the data in a family of 
    /// GeomSubsets.
    /// 
    /// \return Returns false upon failure to create or set the appropriate
    /// attribute on \p geom.
    USDGEOM_API
    static bool SetFamilyType(
        const UsdGeomImageable &geom, 
        const TfToken &familyName, 
        const TfToken &familyType);

    /// Returns the type of family that the GeomSubsets on the given geometric 
    /// prim \p geom, with the given family name, \p familyName belong to. 
    /// 
    /// This only returns the token that's encoded on \p geom and does not perform 
    /// any actual validation on the family of GeomSubsets. Please use 
    /// ValidateFamily() for such validation.
    /// 
    /// When familyType is not set on \p geom, the fallback value 
    /// UsdTokens->unrestricted is returned.
    USDGEOM_API
    static TfToken GetFamilyType(
        const UsdGeomImageable &geom, 
        const TfToken &familyName);

    /// Utility for getting the list of indices that are not assigned to any of 
    /// the GeomSubsets in the \p familyName family on the given \p geom at the 
    /// timeCode, \p time, given the element count (total number of indices in 
    /// the array being subdivided).
    ///
    /// For \p elementType UsdGeomTokens->edge, the output array of indices 
    /// should be interpreted in pairs, as each sequential pair of indices
    /// corresponds to an edge between the two points. Each edge will be in
    /// the order (lowIndex, highIndex).
    ///
    /// If the \p elementType is not applicable to the given \p geom, an empty
    /// array is returned and a coding error is issued.
    USDGEOM_API
    static VtIntArray GetUnassignedIndices(
        const UsdGeomImageable &geom, 
        const TfToken &elementType,
        const TfToken &familyName,
        const UsdTimeCode &time=UsdTimeCode::EarliestTime());

    /// \deprecated Please use GetUnassignedIndices(geom, elementType,
    /// familyName, time) instead.
    /// Utility for getting the list of indices that are not assigned to any of 
    /// the GeomSubsets in \p subsets at the timeCode, \p time, given the 
    /// element count (total number of indices in the array being subdivided), 
    /// \p elementCount.
    USDGEOM_API
    static VtIntArray GetUnassignedIndices(
        const std::vector<UsdGeomSubset> &subsets,
        const size_t elementCount,
        const UsdTimeCode &time=UsdTimeCode::EarliestTime());

    /// \deprecated Please use UsdGeomSubset::ValidateFamily instead.
    /// Validates the data in the given set of GeomSubsets, \p subsets, given 
    /// the total number of elements in the array being subdivided,
    /// \p elementCount and the \p familyType that the subsets belong to.  
    /// 
    /// For proper validation of indices in \p subsets, all of the GeomSubsets 
    /// must have the same 'elementType'.
    /// 
    /// If one or more subsets contain invalid data, then false is returned and 
    /// \p reason is populated with a string explaining the reason why it is 
    /// invalid.
    ///
    /// The python version of this method returns a tuple containing 
    /// a (bool, string), where the bool has the validity of the subsets and 
    /// the string contains the reason (if they're invalid).
    /// 
    USDGEOM_API
    static bool ValidateSubsets(
        const std::vector<UsdGeomSubset> &subsets,
        const size_t elementCount,
        const TfToken &familyType,
        std::string * const reason);

    /// Validates whether the family of subsets identified by the given 
    /// \p familyName and \p elementType on the given imageable, \p geom contain 
    /// valid data. If the family is designated as a partition or as 
    /// non-overlapping using SetFamilyType(), then the validity of the data 
    /// is checked. If the familyType is "unrestricted", then this performs only
    /// bounds checking of the values in the "indices" arrays.
    /// 
    /// If \p reason is not NULL, then it is populated with a string explaining 
    /// why the family is invalid, if it is invalid.
    /// 
    /// The python version of this method returns a tuple containing 
    /// a (bool, string), where the bool has the validity of the family and 
    /// the string contains the reason (if it's invalid).
    /// 
    USDGEOM_API
    static bool ValidateFamily(
        const UsdGeomImageable &geom, 
        const TfToken &elementType,
        const TfToken &familyName,
        std::string * const reason);

private:
    /// Utility to get index pairs at time \p t from the indices attribute 
    /// where every sequential pair of indices is interpreted as an edge or segment.
    /// If \p preserveOrder is true (used for segments), the pairs are directly 
    /// interpreted from the indices attribute with no order modification. If 
    /// \p preserveOrder is false (used for edges), returned pairs are stored in
    /// the order (lowIndex, highIndex). Assumes the elementType is edge or segment.
    VtVec2iArray _GetIndexPairs(const UsdTimeCode t, bool preserveOrder) const;
};

PXR_NAMESPACE_CLOSE_SCOPE

#endif