interleavedMemoryManager.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_ST_INTERLEAVED_MEMORY_MANAGER_H
#define PXR_IMAGING_HD_ST_INTERLEAVED_MEMORY_MANAGER_H

#include "pxr/pxr.h"
#include "pxr/imaging/hdSt/api.h"
#include "pxr/imaging/hdSt/bufferArrayRange.h"
#include "pxr/imaging/hd/bufferArray.h"
#include "pxr/imaging/hd/bufferSpec.h"
#include "pxr/imaging/hd/bufferSource.h"
#include "pxr/imaging/hd/resource.h"
#include "pxr/imaging/hd/strategyBase.h"
#include "pxr/imaging/hd/tokens.h"
#include "pxr/imaging/hd/version.h"
#include "pxr/imaging/hgi/buffer.h"
#include "pxr/base/tf/mallocTag.h"
#include "pxr/base/tf/token.h"

#include <memory>
#include <list>
#include <unordered_map>

PXR_NAMESPACE_OPEN_SCOPE

class HdStResourceRegistry;
struct HgiBufferCpuToGpuOp;

class HdStInterleavedMemoryManager : public HdAggregationStrategy {
protected:
    class _StripedInterleavedBuffer;

    class _StripedInterleavedBufferRange : public HdStBufferArrayRange
    {
    public:
        _StripedInterleavedBufferRange(HdStResourceRegistry* resourceRegistry)
        : HdStBufferArrayRange(resourceRegistry)
        , _stripedBuffer(nullptr)
        , _index(NOT_ALLOCATED)
        , _numElements(1)
        , _capacity(0) {}

        HDST_API
        ~_StripedInterleavedBufferRange() override;

        bool IsValid() const override {
            // note: a range is valid even its index is NOT_ALLOCATED.
            return (bool)_stripedBuffer;
        }

        HDST_API
        bool IsAssigned() const override;

        bool IsImmutable() const override;

        bool RequiresStaging() const override;

        HDST_API
        bool Resize(int numElements) override;

        HDST_API
        void CopyData(HdBufferSourceSharedPtr const &bufferSource) override;

        HDST_API
        VtValue ReadData(TfToken const &name) const override;

        int GetElementOffset() const override {
            return _index;
        }

        int GetByteOffset(TfToken const& resourceName) const override {
            TF_UNUSED(resourceName);
            if (!TF_VERIFY(_stripedBuffer) ||
                !TF_VERIFY(_index != NOT_ALLOCATED)) return 0;
            return _stripedBuffer->GetStride() * _index;
        }

        size_t GetNumElements() const override {
            return _numElements;
        }

        size_t GetVersion() const override {
            return _stripedBuffer->GetVersion();
        }

        int GetElementStride() const override {
            return _stripedBuffer->GetElementStride();
        }

        void IncrementVersion() override {
            _stripedBuffer->IncrementVersion();
        }

        HDST_API
        size_t GetMaxNumElements() const override;

        HDST_API
        HdBufferArrayUsageHint GetUsageHint() const override;

        HDST_API
        HdStBufferResourceSharedPtr GetResource() const override;

        HDST_API
        HdStBufferResourceSharedPtr GetResource(TfToken const& name) override;

        HDST_API
        HdStBufferResourceNamedList const& GetResources() const override;

        HDST_API
        void SetBufferArray(HdBufferArray *bufferArray) override;

        HDST_API
        void DebugDump(std::ostream &out) const override;

        void SetIndex(int index) {
            _index = index;
        }

        void Invalidate() {
            _stripedBuffer = nullptr;
        }

        int GetCapacity() const {
            return _capacity;
        }

        void SetCapacity(int capacity) {
            _capacity = capacity;
        }

    protected:
        HDST_API
        const void *_GetAggregation() const override;

    private:
        enum { NOT_ALLOCATED = -1 };
        _StripedInterleavedBuffer *_stripedBuffer;
        int _index;
        size_t _numElements;
        int _capacity;
    };

    using _StripedInterleavedBufferSharedPtr =
        std::shared_ptr<_StripedInterleavedBuffer>;
    using _StripedInterleavedBufferRangeSharedPtr =
        std::shared_ptr<_StripedInterleavedBufferRange>;
    using _StripedInterleavedBufferRangePtr =
        std::weak_ptr<_StripedInterleavedBufferRange>;

    class _StripedInterleavedBuffer : public HdBufferArray {
    public:
        HDST_API
        _StripedInterleavedBuffer(HdStInterleavedMemoryManager* mgr,
                                  HdStResourceRegistry* resourceRegistry,
                                  TfToken const &role,
                                  HdBufferSpecVector const &bufferSpecs,
                                  HdBufferArrayUsageHint usageHint,
                                  int bufferOffsetAlignment,
                                  int structAlignment,
                                  size_t maxSize,
                                  TfToken const &garbageCollectionPerfToken);

        HDST_API
        virtual ~_StripedInterleavedBuffer();

        HDST_API
        virtual bool GarbageCollect();

        HDST_API
        virtual void DebugDump(std::ostream &out) const;

        HDST_API
        virtual void Reallocate(
                std::vector<HdBufferArrayRangeSharedPtr> const &ranges,
                HdBufferArraySharedPtr const &curRangeOwner);

        void SetNeedsReallocation() {
            _needsReallocation = true;
        }

        void SetNeedsCompaction() {
            _needsCompaction = true;
        }

        size_t GetStride() const {
            return _stride;
        }
        
        size_t GetElementStride() const {
            return _elementStride;
        }


        HDST_API
        HdStBufferResourceSharedPtr GetResource() const;

        HDST_API
        HdStBufferResourceSharedPtr GetResource(TfToken const& name);

        HdStBufferResourceNamedList const& GetResources() const {return _resourceList;}

        HDST_API
        HdBufferSpecVector GetBufferSpecs() const;

        HdStInterleavedMemoryManager*
        GetManager() const {
            return _manager;
        }

    protected:
        HDST_API
        void _DeallocateResources();

        HDST_API
        HdStBufferResourceSharedPtr _AddResource(TfToken const& name,
                                                   HdTupleType tupleType,
                                                   int offset,
                                                   int stride);

    private:
        HdStInterleavedMemoryManager* _manager;
        HdStResourceRegistry* const _resourceRegistry;
        bool _needsCompaction;
        size_t _stride;
        int _bufferOffsetAlignment;  // ranged binding offset alignment
        size_t _maxSize;             // maximum size of single buffer

        // _elementStride is similar to _stride but does account for any buffer
        // offset alignment. If there are multiple elements in a buffer, this 
        // will be the actual byte distance between the two values. 
        // For example, imagine there are three buffers (A, B, C) in a buffer 
        // array, and each buffer has two elements. 
        // +------------------------------------------------------------+
        // | a1 | b1 | c1 | a2 | b2 | c2 | padding for offset alignment |
        // +------------------------------------------------------------+
        // The _stride will be the size of a1 + b1 + c1 + padding, while the
        // _elementStride will be the size of a1 + b1 + c1.
        size_t _elementStride; 

        HdStBufferResourceNamedList _resourceList;

        _StripedInterleavedBufferRangeSharedPtr _GetRangeSharedPtr(size_t idx) const {
            return std::static_pointer_cast<_StripedInterleavedBufferRange>(GetRange(idx).lock());
        }

    };
    
    HdStInterleavedMemoryManager(HdStResourceRegistry* resourceRegistry)
        : _resourceRegistry(resourceRegistry) {}

    HdBufferArrayRangeSharedPtr CreateBufferArrayRange() override;

    HdBufferSpecVector GetBufferSpecs(
        HdBufferArraySharedPtr const &bufferArray) const override;

    size_t GetResourceAllocation(
        HdBufferArraySharedPtr const &bufferArray, 
        VtDictionary &result) const override;
    
    HdStResourceRegistry* const _resourceRegistry;
};

class HdStInterleavedUBOMemoryManager : public HdStInterleavedMemoryManager {
public:
    HdStInterleavedUBOMemoryManager(HdStResourceRegistry* resourceRegistry)
    : HdStInterleavedMemoryManager(resourceRegistry) {}

    HDST_API
    virtual HdBufferArraySharedPtr CreateBufferArray(
        TfToken const &role,
        HdBufferSpecVector const &bufferSpecs,
        HdBufferArrayUsageHint usageHint);

    HDST_API
    virtual AggregationId ComputeAggregationId(
        HdBufferSpecVector const &bufferSpecs,
        HdBufferArrayUsageHint usageHint) const;
};

class HdStInterleavedSSBOMemoryManager : public HdStInterleavedMemoryManager {
public:
    HdStInterleavedSSBOMemoryManager(HdStResourceRegistry* resourceRegistry)
    : HdStInterleavedMemoryManager(resourceRegistry) {}

    HDST_API
    virtual HdBufferArraySharedPtr CreateBufferArray(
        TfToken const &role,
        HdBufferSpecVector const &bufferSpecs,
        HdBufferArrayUsageHint usageHint);

    HDST_API
    virtual AggregationId ComputeAggregationId(
        HdBufferSpecVector const &bufferSpecs,
        HdBufferArrayUsageHint usageHint) const;
};

PXR_NAMESPACE_CLOSE_SCOPE

#endif  // PXR_IMAGING_HD_ST_INTERLEAVED_MEMORY_MANAGER_H