lightLinkingSceneIndex.h

//
// Copyright 2024 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_IMAGING_HDSI_LIGHT_LINKING_SCENE_INDEX_H
#define PXR_IMAGING_HDSI_LIGHT_LINKING_SCENE_INDEX_H

#include "pxr/pxr.h"
#include "pxr/imaging/hdsi/api.h"

#include "pxr/imaging/hd/collectionExpressionEvaluator.h"
#include "pxr/imaging/hd/collectionPredicateLibrary.h"
#include "pxr/imaging/hd/filteringSceneIndex.h"
#include "pxr/usd/sdf/path.h"
#include "pxr/base/tf/staticTokens.h"
#include "pxr/base/tf/token.h"
#include "pxr/base/vt/array.h"

#include <memory>

PXR_NAMESPACE_OPEN_SCOPE

#define HDSI_LIGHT_LINKING_SCENE_INDEX_TOKENS   \
    (lightPrimTypes)                            \
    (lightFilterPrimTypes)                      \
    (geometryPrimTypes)

TF_DECLARE_PUBLIC_TOKENS(HdsiLightLinkingSceneIndexTokens, HDSI_API,
    HDSI_LIGHT_LINKING_SCENE_INDEX_TOKENS);

namespace HdsiLightLinkingSceneIndex_Impl
{
    struct _Cache;
    using _CacheSharedPtr = std::shared_ptr<_Cache>;
}

TF_DECLARE_REF_PTRS(HdsiLightLinkingSceneIndex);

//        Linking to instance proxy prims, nested instances and
class HdsiLightLinkingSceneIndex : public HdSingleInputFilteringSceneIndexBase
{
public:
    HDSI_API
    static HdSceneIndexBaseRefPtr
    New(const HdSceneIndexBaseRefPtr &inputSceneIndex,
        const HdContainerDataSourceHandle &inputArgs,
        const HdCollectionPredicateLibrary &predicateLibrary);

    // Old signature that doesn't provide a predicate library. An empty
    // library will be used in this case.
    HDSI_API
    static HdSceneIndexBaseRefPtr
    New(const HdSceneIndexBaseRefPtr &inputSceneIndex,
        const HdContainerDataSourceHandle &inputArgs);

    HDSI_API
    HdSceneIndexPrim GetPrim(const SdfPath &primPath) const override;

    HDSI_API
    SdfPathVector GetChildPrimPaths(const SdfPath &primPath) const override;

    HDSI_API
    HdCollectionExpressionEvaluator MakeEvaluator(
        const SdfPathExpression &expr) const;

protected:

    HDSI_API
    HdsiLightLinkingSceneIndex(
        const HdSceneIndexBaseRefPtr &inputSceneIndex,
        const HdContainerDataSourceHandle &inputArgs,
        const HdCollectionPredicateLibrary &predicateLibrary);

    HDSI_API
    void _PrimsAdded(
        const HdSceneIndexBase &sender,
        const HdSceneIndexObserver::AddedPrimEntries &entries) override;

    HDSI_API
    void _PrimsRemoved(
        const HdSceneIndexBase &sender,
        const HdSceneIndexObserver::RemovedPrimEntries &entries) override;

    HDSI_API
    void _PrimsDirtied(
        const HdSceneIndexBase &sender,
        const HdSceneIndexObserver::DirtiedPrimEntries &entries) override;

private:
    void _ProcessAddedLightOrFilter(
        const HdSceneIndexObserver::AddedPrimEntry &entry,
        const TfTokenVector &collectionNames,
        HdSceneIndexObserver::DirtiedPrimEntries *dirtiedEntries);

    bool _IsLight(const TfToken &primType) const;
    bool _IsLightFilter(const TfToken &primType) const;
    bool _IsGeometry(const TfToken &primType) const;

private:
    HdsiLightLinkingSceneIndex_Impl::_CacheSharedPtr const _cache;

    // Track prims with light linking collections.
    SdfPathSet _lightAndFilterPrimPaths;

    const VtArray<TfToken> _lightPrimTypes;
    const VtArray<TfToken> _lightFilterPrimTypes;
    const VtArray<TfToken> _geometryPrimTypes;

    const HdCollectionPredicateLibrary _predicateLibrary;

    // Flag tracking first population.
    bool _wasPopulated;
};

PXR_NAMESPACE_CLOSE_SCOPE

#endif