bufferArray.h

//
// Copyright 2016 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_BUFFER_ARRAY_H
#define PXR_IMAGING_HD_BUFFER_ARRAY_H
 
#include "pxr/pxr.h"
#include "pxr/imaging/hd/api.h"
#include "pxr/imaging/hd/version.h"
#include "pxr/imaging/hd/bufferSpec.h"
#include "pxr/base/tf/token.h"
#include "pxr/base/vt/value.h"
 
#include <atomic>
#include <memory>
#include <mutex>
 
PXR_NAMESPACE_OPEN_SCOPE
 
 
class HdBufferArrayRange;
 
using HdBufferArraySharedPtr = std::shared_ptr<class HdBufferArray>;
using HdBufferArrayRangeSharedPtr = std::shared_ptr<HdBufferArrayRange>;
using HdBufferArrayRangePtr = std::weak_ptr<HdBufferArrayRange>;
 
enum HdBufferArrayUsageHintBits : uint32_t
{
    HdBufferArrayUsageHintBitsImmutable   = 1 << 0,
    HdBufferArrayUsageHintBitsSizeVarying = 1 << 1,
    HdBufferArrayUsageHintBitsUniform     = 1 << 2,
    HdBufferArrayUsageHintBitsStorage     = 1 << 3,
    HdBufferArrayUsageHintBitsVertex      = 1 << 4,
    HdBufferArrayUsageHintBitsIndex       = 1 << 5,
};
using HdBufferArrayUsageHint = uint32_t;
 
class HdBufferArray : public std::enable_shared_from_this<HdBufferArray> 
{
public:
    HD_API
    HdBufferArray(TfToken const &role,
                  TfToken const garbageCollectionPerfToken,
                  HdBufferArrayUsageHint usageHint);
 
    HD_API
    virtual ~HdBufferArray();
 
    TfToken const& GetRole() const {return _role;}
 
    size_t GetVersion() const {
        return _version;
    }
 
    HD_API
    void IncrementVersion();
 
    HD_API
    bool TryAssignRange(HdBufferArrayRangeSharedPtr &range);
 
    virtual bool GarbageCollect() = 0;
 
    virtual void Reallocate(
        std::vector<HdBufferArrayRangeSharedPtr> const &ranges,
        HdBufferArraySharedPtr const &curRangeOwner) = 0;
 
    HD_API
    virtual size_t GetMaxNumElements() const;
 
    virtual void DebugDump(std::ostream &out) const = 0;
 
    size_t GetRangeCount() const { return _rangeCount; }
 
    HD_API
    HdBufferArrayRangePtr GetRange(size_t idx) const;
 
    HD_API
    void RemoveUnusedRanges();
 
    bool NeedsReallocation() const {
        return _needsReallocation;
    }
 
    bool IsImmutable() const {
        return _usageHint & HdBufferArrayUsageHintBitsImmutable;
    }
 
    HdBufferArrayUsageHint GetUsageHint() const {
        return _usageHint;
    }
 
protected:
    bool _needsReallocation;
 
    void _SetMaxNumRanges(size_t max) { _maxNumRanges = max; }
 
    HD_API
    void _SetRangeList(std::vector<HdBufferArrayRangeSharedPtr> const &ranges);
 
private:
 
    // Do not allow copies.
    HdBufferArray(const HdBufferArray &) = delete;
    HdBufferArray &operator=(const HdBufferArray &) = delete;
 
 
    typedef std::vector<HdBufferArrayRangePtr> _RangeList;
 
    // Vector of ranges associated with this buffer
    // We add values to the list in a multi-threaded fashion
    // but can later remove them in _RemoveUnusedRanges
    // than add more.
    //
    _RangeList         _rangeList;
    std::atomic_size_t _rangeCount;               // how many ranges are valid in list
    std::mutex         _rangeListLock;
 
    const TfToken _role;
    const TfToken _garbageCollectionPerfToken;
 
    size_t _version;
 
    size_t _maxNumRanges;
    HdBufferArrayUsageHint _usageHint;
};
 
 
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif //PXR_IMAGING_HD_BUFFER_ARRAY_H