instancerTopologySchema.h

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//
// Copyright 2023 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
 
/* ************************************************************************** */
/* **                                                                      ** */
/* ** This file is generated by a script.                                  ** */
/* **                                                                      ** */
/* ** Do not edit it directly (unless it is within a CUSTOM CODE section)! ** */
/* ** Edit hdSchemaDefs.py instead to make changes.                        ** */
/* **                                                                      ** */
/* ************************************************************************** */
 
#ifndef PXR_IMAGING_HD_INSTANCER_TOPOLOGY_SCHEMA_H
#define PXR_IMAGING_HD_INSTANCER_TOPOLOGY_SCHEMA_H
 
 
#include "pxr/imaging/hd/api.h"
#include "pxr/imaging/hd/schemaTypeDefs.h"
 
#include "pxr/imaging/hd/schema.h"
 
// --(BEGIN CUSTOM CODE: Includes)--
// --(END CUSTOM CODE: Includes)--
 
PXR_NAMESPACE_OPEN_SCOPE
 
// --(BEGIN CUSTOM CODE: Declares)--
// --(END CUSTOM CODE: Declares)--
 
#define HD_INSTANCER_TOPOLOGY_SCHEMA_TOKENS \
    (instancerTopology) \
    (prototypes) \
    (instanceIndices) \
    (mask) \
    (instanceLocations) \
 
TF_DECLARE_PUBLIC_TOKENS(HdInstancerTopologySchemaTokens, HD_API,
    HD_INSTANCER_TOPOLOGY_SCHEMA_TOKENS);
 
//-----------------------------------------------------------------------------
 
// Since the instancing schema is complicated:
//
// An instancer is a prim at a certain scenegraph location that causes other
// prims to be duplicated. The instancer can also hold instance-varying data
// like constant primvars or material relationships.
//
// The important things an instancer has is:
//
// 1.) Instancer topology, describing how exactly the prims are duplicated;
//
// 2.) Instance-rate data, meaning data that varies per instance, such as
// primvars or material bindings.
//
// If an instancer causes prims "/A" and "/B" to be duplicated, we encode that
// by setting prototypes = ["/A", "/B"]. Note that "/A" and "/B" can be
// subtrees, not direct gprims. instanceIndices encodes both multiplicity and
// position in arrays of instance-rate data, per prototype path; if
// instanceIndices = { [0,2], [1] }, then we draw /A twice (with instance
// primvar indices 0 and 2); and /B once (with instance primvar index 1). Mask
// is an auxiliary parameter that can be used to deactivate certain instances;
// mask = [true, true, false] would disable the second copy of "/A". An empty
// mask array is the same as all-true.
//
// Scenes generally specify instancing in one of two ways:
//
// 1.) Explicit instancing: prim /Instancer wants to draw its subtree at an
// array of locations. This is a data expansion form.
//
// 2.) Implicit instancing: prims /X and /Y are marked as being identical, and
// scene load replaces them with a single prim and an instancer. This is a
// data coalescing form.
//
// For implicit instancing, we want to know the original paths of /X and /Y,
// for doing things like resolving inheritance. This is encoded in the
// "instanceLocations" path, while the prototype prims (e.g. /_Prototype/Cube,
// the deduplicated version of /X/Cube and /Y/Cube) is encoded in the
// "prototypes" path.
//
// For explicit instancing, the "instanceLocations" attribute is meaningless
// and should be left null.
//
 
class HdInstancerTopologySchema : public HdSchema
{
public:
 
    HdInstancerTopologySchema(HdContainerDataSourceHandle container)
      : HdSchema(container) {}
 
    HD_API
    static HdInstancerTopologySchema GetFromParent(
        const HdContainerDataSourceHandle &fromParentContainer);
 
 
// --(BEGIN CUSTOM CODE: Schema Methods)--
 
    HD_API
    VtArray<int> ComputeInstanceIndicesForProto(SdfPath const &path);
 
// --(END CUSTOM CODE: Schema Methods)--
 
 
    HD_API
    HdPathArrayDataSourceHandle GetPrototypes() const;
 
    HD_API
    HdIntArrayVectorSchema GetInstanceIndices() const;
 
    HD_API
    HdBoolArrayDataSourceHandle GetMask() const;
 
    HD_API
    HdPathArrayDataSourceHandle GetInstanceLocations() const; 
 
 
 
    HD_API
    static const TfToken &GetSchemaToken();
 
    HD_API
    static const HdDataSourceLocator &GetDefaultLocator();
 
 
 
    HD_API
    static HdContainerDataSourceHandle
    BuildRetained(
        const HdPathArrayDataSourceHandle &prototypes,
        const HdVectorDataSourceHandle &instanceIndices,
        const HdBoolArrayDataSourceHandle &mask,
        const HdPathArrayDataSourceHandle &instanceLocations
    );
 
    class Builder
    {
    public:
        HD_API
        Builder &SetPrototypes(
            const HdPathArrayDataSourceHandle &prototypes);
        HD_API
        Builder &SetInstanceIndices(
            const HdVectorDataSourceHandle &instanceIndices);
        HD_API
        Builder &SetMask(
            const HdBoolArrayDataSourceHandle &mask);
        HD_API
        Builder &SetInstanceLocations(
            const HdPathArrayDataSourceHandle &instanceLocations);
 
        HD_API
        HdContainerDataSourceHandle Build();
 
    private:
        HdPathArrayDataSourceHandle _prototypes;
        HdVectorDataSourceHandle _instanceIndices;
        HdBoolArrayDataSourceHandle _mask;
        HdPathArrayDataSourceHandle _instanceLocations;
 
    };
 
};
 
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif