vboSimpleMemoryManager.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_VBO_SIMPLE_MEMORY_MANAGER_H
#define PXR_IMAGING_HD_ST_VBO_SIMPLE_MEMORY_MANAGER_H

#include "pxr/pxr.h"
#include "pxr/imaging/hdSt/api.h"
#include "pxr/imaging/hdSt/bufferArrayRange.h"
#include "pxr/imaging/hdSt/resourceRegistry.h"
#include "pxr/imaging/hd/version.h"
#include "pxr/imaging/hd/strategyBase.h"
#include "pxr/imaging/hd/bufferArray.h"
#include "pxr/imaging/hd/bufferSpec.h"
#include "pxr/imaging/hd/bufferSource.h"

PXR_NAMESPACE_OPEN_SCOPE

class HdStResourceRegistry;

class HdStVBOSimpleMemoryManager : public HdAggregationStrategy
{
public:
    HdStVBOSimpleMemoryManager(HdStResourceRegistry* resourceRegistry)
        : _resourceRegistry(resourceRegistry) {}
    
    HDST_API
    virtual HdBufferArraySharedPtr CreateBufferArray(
        TfToken const &role,
        HdBufferSpecVector const &bufferSpecs,
        HdBufferArrayUsageHint usageHint);

    HDST_API
    virtual HdBufferArrayRangeSharedPtr CreateBufferArrayRange();

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

    virtual HdBufferSpecVector GetBufferSpecs(
        HdBufferArraySharedPtr const &bufferArray) const;

    virtual size_t GetResourceAllocation(
        HdBufferArraySharedPtr const &bufferArray, 
        VtDictionary &result) const;

protected:
    class _SimpleBufferArray;

    class _SimpleBufferArrayRange final : public HdStBufferArrayRange
    {
    public:
        _SimpleBufferArrayRange(HdStResourceRegistry* resourceRegistry)
            : HdStBufferArrayRange(resourceRegistry)
            , _bufferArray(nullptr)
            , _numElements(0) {
        }

        bool IsValid() const override {
            return (bool)_bufferArray;
        }

        HDST_API
        bool IsAssigned() const override;

        bool IsImmutable() const override;

        bool RequiresStaging() const override;
    
        bool Resize(int numElements) override {
            _numElements = numElements;
            return _bufferArray->Resize(numElements);
        }

        HDST_API
        void CopyData(HdBufferSourceSharedPtr const &bufferSource) override;

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

        int GetElementOffset() const override {
            return 0;
        }

        int GetByteOffset(TfToken const& resourceName) const override {
            TF_UNUSED(resourceName);
            return 0;
        }

        size_t GetNumElements() const override {
            return _numElements;
        }

        int GetCapacity() const {
            return _bufferArray->GetCapacity();
        }

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

        void IncrementVersion() override {
            _bufferArray->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 Invalidate() {
            _bufferArray = NULL;
        }

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

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

    private:
        _SimpleBufferArray * _bufferArray;
        size_t _numElements;
    };

    using _SimpleBufferArraySharedPtr =
        std::shared_ptr<_SimpleBufferArray>;
    using _SimpleBufferArrayRangeSharedPtr =
        std::shared_ptr<_SimpleBufferArrayRange>;
    using _SimpleBufferArrayRangePtr =
        std::weak_ptr<_SimpleBufferArrayRange>;

    class _SimpleBufferArray final : public HdBufferArray
    {
    public:
        HDST_API
        _SimpleBufferArray(HdStResourceRegistry* resourceRegistry,
                           TfToken const &role,
                           HdBufferSpecVector const &bufferSpecs,
                           HdBufferArrayUsageHint usageHint);

        HDST_API
        ~_SimpleBufferArray() override;

        HDST_API
        bool GarbageCollect() override;

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

        HDST_API
        bool Resize(int numElements);

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

        HDST_API
        size_t GetMaxNumElements() const override;

        int GetCapacity() const {
            return _capacity;
        }


        HDST_API
        HdStBufferResourceSharedPtr GetResource() const;

        HDST_API
        HdStBufferResourceSharedPtr GetResource(TfToken const& name);

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

        HDST_API
        HdBufferSpecVector GetBufferSpecs() const;

    protected:
        HDST_API
        void _DeallocateResources();

        HDST_API
        HdStBufferResourceSharedPtr _AddResource(TfToken const& name,
                                                   HdTupleType tupleType,
                                                   int offset,
                                                   int stride);
    private:
        HdStResourceRegistry* const _resourceRegistry;
        int _capacity;
        size_t _maxBytesPerElement;

        HdStBufferResourceNamedList _resourceList;

        _SimpleBufferArrayRangeSharedPtr _GetRangeSharedPtr() const {
            return GetRangeCount() > 0
                ? std::static_pointer_cast<_SimpleBufferArrayRange>(GetRange(0).lock())
                : _SimpleBufferArrayRangeSharedPtr();
        }
    };
    
    HdStResourceRegistry* const _resourceRegistry;
};

PXR_NAMESPACE_CLOSE_SCOPE

#endif  // PXR_IMAGING_HD_ST_VBO_SIMPLE_MEMORY_MANAGER_H