sceneIndexPluginRegistry.h

//
// Copyright 2021 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
//    names, trademarks, service marks, or product names of the Licensor
//    and its affiliates, except as required to comply with Section 4(c) of
//    the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
#ifndef PXR_IMAGING_HD_SCENE_INDEX_PLUGIN_REGISTRY_H
#define PXR_IMAGING_HD_SCENE_INDEX_PLUGIN_REGISTRY_H

#include "pxr/pxr.h"
#include "pxr/base/tf/singleton.h"
#include "pxr/base/tf/staticTokens.h"
#include "pxr/imaging/hf/pluginRegistry.h"
#include "pxr/imaging/hd/api.h"
#include "pxr/imaging/hd/sceneIndex.h"

PXR_NAMESPACE_OPEN_SCOPE

#define HDSCENEINDEXPLUGINREGISTRY_TOKENS \
    ((rendererDisplayName, "__rendererDisplayName")) \


TF_DECLARE_PUBLIC_TOKENS(HdSceneIndexPluginRegistryTokens, HD_API,
    HDSCENEINDEXPLUGINREGISTRY_TOKENS);



class HdSceneIndexPlugin;

class HdSceneIndexPluginRegistry final  : public HfPluginRegistry
{
public:
    HD_API
    static HdSceneIndexPluginRegistry &GetInstance();

    template<typename T, typename... Bases>
    static void Define();

    HD_API
    HdSceneIndexBaseRefPtr AppendSceneIndex(
        const TfToken &sceneIndexPluginId,
        const HdSceneIndexBaseRefPtr &inputScene,
        const HdContainerDataSourceHandle &inputArgs);

    HD_API
    HdSceneIndexBaseRefPtr AppendSceneIndicesForRenderer(
        const std::string &rendererDisplayName,
        const HdSceneIndexBaseRefPtr &inputScene);

    enum InsertionOrder
    {
        InsertionOrderAtStart,
        InsertionOrderAtEnd,
    };

    using InsertionPhase = unsigned int;

    HD_API
    void RegisterSceneIndexForRenderer(
        const std::string &rendererDisplayName,
        const TfToken &sceneIndexPluginId,
        const HdContainerDataSourceHandle &inputArgs,
        InsertionPhase insertionPhase,
        InsertionOrder insertionOrder);

protected:

     void _CollectAdditionalMetadata(
        const PlugRegistry &plugRegistry, const TfType &pluginType) override;

private:
    friend class TfSingleton<HdSceneIndexPluginRegistry>;
    
    // Singleton gets private constructed
    HdSceneIndexPluginRegistry();
    ~HdSceneIndexPluginRegistry() override;

    HdSceneIndexPlugin *_GetSceneIndexPlugin(const TfToken &pluginId);

    struct _Entry
    {
        _Entry(const TfToken &sceneIndexPluginId,
                const HdContainerDataSourceHandle &args)
        : sceneIndexPluginId(sceneIndexPluginId)
        , args(args)
        {}

        TfToken sceneIndexPluginId;
        HdContainerDataSourceHandle args;
    };

    using _EntryList = std::vector<_Entry>;
    using _PhasesMap = std::map<InsertionPhase, _EntryList>;
    using _RenderersMap = std::map<std::string, _PhasesMap>;

    HdSceneIndexBaseRefPtr _AppendForPhases(
        const HdSceneIndexBaseRefPtr &inputScene,
        const _PhasesMap &phasesMap,
        const HdContainerDataSourceHandle &argsUnderlay);

    _RenderersMap _sceneIndicesForRenderers;

    // Used to track plugins whose plugInfo entries contain "loadWithRenderer"
    // values to load when the specified renderer or renderers are used.
    // Loading the plug-in allows for further registration code to run when
    // a plug-in wouldn't be loaded elsewhere.
    using _PreloadMap = std::map<std::string, TfTokenVector>;
    _PreloadMap _preloadsForRenderer;

};

template<typename T, typename... Bases>
void HdSceneIndexPluginRegistry::Define()
{
    HfPluginRegistry::Define<T, HdSceneIndexPlugin, Bases...>();
}

PXR_NAMESPACE_CLOSE_SCOPE

#endif // PXR_IMAGING_HD_SCENE_INDEX_PLUGIN_REGISTRY_H