dataSource.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_DATASOURCE_H
#define PXR_IMAGING_HD_DATASOURCE_H

#include "pxr/pxr.h"

#include "pxr/imaging/hd/api.h"
#include "pxr/imaging/hd/dataSourceLocator.h"

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

#include <iosfwd>
#include <memory>
#include <vector>
#include <atomic>

PXR_NAMESPACE_OPEN_SCOPE

#define HD_DECLARE_DATASOURCE_ABSTRACT(type) \
    using Handle =  std::shared_ptr<type>; \
    using AtomicHandle = Handle; \
    static Handle AtomicLoad(AtomicHandle &ptr) { \
        return std::atomic_load(&ptr); \
    } \
    static void AtomicStore(AtomicHandle &ptr, const Handle &v) { \
        std::atomic_store(&ptr, v); \
    } \
    static Handle Cast(const HdDataSourceBase::Handle &v) { \
        return std::dynamic_pointer_cast<type>(v); \
    }

#define HD_DECLARE_DATASOURCE(type) \
    HD_DECLARE_DATASOURCE_ABSTRACT(type) \
    template <typename ... Args> \
    static Handle New(Args&& ... args) { \
        return Handle(new type(std::forward<Args>(args) ... )); \
    }

#define HD_DECLARE_DATASOURCE_HANDLES(type) \
    using type##Handle = type::Handle; \
    using type##AtomicHandle = type::AtomicHandle;

class HdDataSourceBase
{
public:
    HD_DECLARE_DATASOURCE_ABSTRACT(HdDataSourceBase)
    
    HD_API 
    virtual ~HdDataSourceBase() = 0;
};

HD_DECLARE_DATASOURCE_HANDLES(HdDataSourceBase);

class HdContainerDataSource : public HdDataSourceBase
{
public:
    HD_DECLARE_DATASOURCE_ABSTRACT(HdContainerDataSource);

    virtual bool Has(const TfToken &name) = 0;

    virtual TfTokenVector GetNames() = 0;

    virtual HdDataSourceBaseHandle Get(const TfToken &name) = 0;

    HD_API 
    static HdDataSourceBaseHandle Get(
        const Handle &container,
        const HdDataSourceLocator &locator);
};

HD_DECLARE_DATASOURCE_HANDLES(HdContainerDataSource);

class HdVectorDataSource : public HdDataSourceBase
{ 
public:
    HD_DECLARE_DATASOURCE_ABSTRACT(HdVectorDataSource);

    virtual size_t GetNumElements() = 0;

    virtual HdDataSourceBaseHandle GetElement(size_t element) = 0;
};

HD_DECLARE_DATASOURCE_HANDLES(HdVectorDataSource);

class HdSampledDataSource : public HdDataSourceBase
{
public:
    HD_DECLARE_DATASOURCE_ABSTRACT(HdSampledDataSource);
    using Time = float;

    virtual VtValue GetValue(Time shutterOffset) = 0;

    virtual bool GetContributingSampleTimesForInterval(
        Time startTime, 
        Time endTime,
        std::vector<Time> * outSampleTimes) = 0;
};

HD_DECLARE_DATASOURCE_HANDLES(HdSampledDataSource);

template <typename T>
class HdTypedSampledDataSource : public HdSampledDataSource
{
public:
    HD_DECLARE_DATASOURCE_ABSTRACT(HdTypedSampledDataSource<T>);
    using Type = T;

    virtual T GetTypedValue(Time shutterOffset) = 0;
};


class HdBlockDataSource : public HdDataSourceBase
{
public:
    HD_DECLARE_DATASOURCE(HdBlockDataSource);

    HdBlockDataSource(){}
};

HD_DECLARE_DATASOURCE_HANDLES(HdBlockDataSource);

// Utilities //////////////////////////////////////////////////////////////////

HD_API
bool
HdGetMergedContributingSampleTimesForInterval(
    size_t count,
    const HdSampledDataSourceHandle *inputDataSources,
    HdSampledDataSource::Time startTime,
    HdSampledDataSource::Time endTime,
    std::vector<HdSampledDataSource::Time> * outSampleTimes);

void HdDebugPrintDataSource(
    std::ostream &,
    HdDataSourceBaseHandle,
    int indentLevel = 0);

void HdDebugPrintDataSource(HdDataSourceBaseHandle, int indentLevel = 0);

PXR_NAMESPACE_CLOSE_SCOPE

#endif // PXR_IMAGING_HD_DATASOURCE_H