/*
-----------------------------------------------------------------------------
This source file is part of OGRE-Next
    (Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2014 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-----------------------------------------------------------------------------
*/
#ifndef __HardwareBufferManager__
#define __HardwareBufferManager__

// Precompiler options
#include "OgrePrerequisites.h"

#include "OgreHardwareIndexBuffer.h"
#include "OgreHardwareVertexBuffer.h"
#include "OgreHlmsManager.h"  //For OGRE_HLMS_NUM_INPUT_LAYOUTS
#include "OgreSingleton.h"
#include "Threading/OgreThreadHeaders.h"

#include "OgreHeaderPrefix.h"

namespace Ogre
{
    namespace v1
    {
        /** \addtogroup Core
         *  @{
         */
        /** \addtogroup RenderSystem
         *  @{
         */

        /** Abstract interface representing a 'licensee' of a hardware buffer copy.
        @remarks
            Often it's useful to have temporary buffers which are used for working
            but are not necessarily needed permanently. However, creating and
            destroying buffers is expensive, so we need a way to share these
            working areas, especially those based on existing fixed buffers.
            This class represents a licensee of one of those temporary buffers,
            and must be implemented by any user of a temporary buffer if they
            wish to be notified when the license is expired.
        */
        class _OgreExport HardwareBufferLicensee
        {
        public:
            virtual ~HardwareBufferLicensee() {}
            /** This method is called when the buffer license is expired and is about
                to be returned to the shared pool.
            */
            virtual void licenseExpired( HardwareBuffer *buffer ) = 0;
        };

        /** Structure for recording the use of temporary blend buffers. */
        class _OgreExport TempBlendedBufferInfo : public HardwareBufferLicensee, public OgreAllocatedObj
        {
        private:
            // Pre-blended
            HardwareVertexBufferSharedPtr srcPositionBuffer;
            HardwareVertexBufferSharedPtr srcNormalBuffer;
            // Post-blended
            HardwareVertexBufferSharedPtr destPositionBuffer;
            HardwareVertexBufferSharedPtr destNormalBuffer;
            /// Both positions and normals are contained in the same buffer.
            bool           posNormalShareBuffer;
            unsigned short posBindIndex;
            unsigned short normBindIndex;
            bool           bindPositions;
            bool           bindNormals;

        public:
            ~TempBlendedBufferInfo() override;
            /// Utility method, extract info from the given VertexData.
            void extractFrom( const VertexData *sourceData );
            /// Utility method, checks out temporary copies of src into dest.
            void checkoutTempCopies( bool positions = true, bool normals = true );
            /// Utility method, binds dest copies into a given VertexData struct.
            void bindTempCopies( VertexData *targetData, bool suppressHardwareUpload );
            /** Overridden member from HardwareBufferLicensee. */
            void licenseExpired( HardwareBuffer *buffer ) override;
            /** Detect currently have buffer copies checked out and touch it. */
            bool buffersCheckedOut( bool positions = true, bool normals = true ) const;
        };

        /** Base definition of a hardware buffer manager.
        @remarks
            This class is deliberately not a Singleton, so that multiple types can
            exist at once. The Singleton is wrapped via the Decorator pattern
            in HardwareBufferManager, below. Each concrete implementation should
            provide a subclass of HardwareBufferManagerBase, which does the actual
            work, and also a very simple subclass of HardwareBufferManager which
            simply constructs the instance of the HardwareBufferManagerBase subclass
            and passes it to the HardwareBufferManager superclass as a delegate.
            This subclass must also delete the implementation instance it creates.
        */
        class _OgreExport HardwareBufferManagerBase : public OgreAllocatedObj
        {
            friend class HardwareVertexBufferSharedPtr;
            friend class HardwareIndexBufferSharedPtr;

        protected:
            /** WARNING: The following two members should place before all other members.
                Members destruct order is very important here, because destructing other
                members will cause notify back to this class, and then will access to this
                two members.
            */
            typedef set<HardwareVertexBuffer *>::type VertexBufferList;
            typedef set<HardwareIndexBuffer *>::type  IndexBufferList;

            VertexBufferList mVertexBuffers;
            IndexBufferList  mIndexBuffers;

            typedef set<VertexDeclaration *>::type   VertexDeclarationList;
            typedef set<VertexBufferBinding *>::type VertexBufferBindingList;

            VertexDeclarationList   mVertexDeclarations;
            VertexBufferBindingList mVertexBufferBindings;

            // Mutexes
            OGRE_MUTEX( mVertexBuffersMutex );
            OGRE_MUTEX( mIndexBuffersMutex );
            OGRE_MUTEX( mVertexDeclarationsMutex );
            OGRE_MUTEX( mVertexBufferBindingsMutex );

            /// Internal method for destroys all vertex declarations.
            virtual void destroyAllDeclarations();
            /// Internal method for destroys all vertex buffer bindings.
            virtual void destroyAllBindings();

            /// Internal method for creates a new vertex declaration, may be overridden by certain
            /// rendering APIs.
            virtual VertexDeclaration *createVertexDeclarationImpl();
            /// Internal method for destroys a vertex declaration, may be overridden by certain rendering
            /// APIs.
            virtual void destroyVertexDeclarationImpl( VertexDeclaration *decl );

            /// Internal method for creates a new VertexBufferBinding, may be overridden by certain
            /// rendering APIs.
            virtual VertexBufferBinding *createVertexBufferBindingImpl();
            /// Internal method for destroys a VertexBufferBinding, may be overridden by certain
            /// rendering APIs.
            virtual void destroyVertexBufferBindingImpl( VertexBufferBinding *binding );

        public:
            enum BufferLicenseType
            {
                /// Licensee will only release buffer when it says so.
                BLT_MANUAL_RELEASE,
                /// Licensee can have license revoked.
                BLT_AUTOMATIC_RELEASE
            };

        protected:
            /** Struct holding details of a license to use a temporary shared buffer. */
            class _OgrePrivate VertexBufferLicense
            {
            public:
                HardwareVertexBuffer         *originalBufferPtr;
                BufferLicenseType             licenseType;
                size_t                        expiredDelay;
                HardwareVertexBufferSharedPtr buffer;
                HardwareBufferLicensee       *licensee;
                VertexBufferLicense( HardwareVertexBuffer *orig, BufferLicenseType ltype, size_t delay,
                                     HardwareVertexBufferSharedPtr buf, HardwareBufferLicensee *lic ) :
                    originalBufferPtr( orig ),
                    licenseType( ltype ),
                    expiredDelay( delay ),
                    buffer( buf ),
                    licensee( lic )
                {
                }
            };

            /// Map from original buffer to temporary buffers.
            typedef multimap<HardwareVertexBuffer *, HardwareVertexBufferSharedPtr>::type
                FreeTemporaryVertexBufferMap;
            /// Map of current available temp buffers.
            FreeTemporaryVertexBufferMap mFreeTempVertexBufferMap;
            /// Map from temporary buffer to details of a license.
            typedef map<HardwareVertexBuffer *, VertexBufferLicense>::type
                TemporaryVertexBufferLicenseMap;
            /// Map of currently licensed temporary buffers.
            TemporaryVertexBufferLicenseMap mTempVertexBufferLicenses;
            /// Number of frames elapsed since temporary buffers utilization was above half the
            /// available.
            size_t mUnderUsedFrameCount;
            /// Number of frames to wait before free unused temporary buffers.
            static const size_t UNDER_USED_FRAME_THRESHOLD;
            /// Frame delay for BLT_AUTOMATIC_RELEASE temporary buffers.
            static const size_t EXPIRED_DELAY_FRAME_THRESHOLD;
            // Mutexes
            OGRE_MUTEX( mTempBuffersMutex );

            /// Creates a new buffer as a copy of the source, does not copy data.
            virtual HardwareVertexBufferSharedPtr makeBufferCopy(
                const HardwareVertexBufferSharedPtr &source, HardwareBuffer::Usage usage,
                bool useShadowBuffer );

        public:
            HardwareBufferManagerBase();
            virtual ~HardwareBufferManagerBase();
            /** Create a hardware vertex buffer.
            @remarks
                This method creates a new vertex buffer; this will act as a source of geometry
                data for rendering objects. Note that because the meaning of the contents of
                the vertex buffer depends on the usage, this method does not specify a
                vertex format; the user of this buffer can actually insert whatever data
                they wish, in any format. However, in order to use this with a RenderOperation,
                the data in this vertex buffer will have to be associated with a semantic element
                of the rendering pipeline, e.g. a position, or texture coordinates. This is done
                using the VertexDeclaration class, which itself contains VertexElement structures
                referring to the source data.
            @remarks Note that because vertex buffers can be shared, they are reference
                counted so you do not need to worry about destroying themm this will be done
                automatically.
            @param vertexSize
                The size in bytes of each vertex in this buffer; you must calculate
                this based on the kind of data you expect to populate this buffer with.
            @param numVerts
                The number of vertices in this buffer.
            @param usage
                One or more members of the HardwareBuffer::Usage enumeration; you are
                strongly advised to use HBU_STATIC_WRITE_ONLY wherever possible, if you need to
                update regularly, consider HBU_DYNAMIC_WRITE_ONLY and useShadowBuffer=true.
            @param useShadowBuffer
                If set to @c true, this buffer will be 'shadowed' by one stored in
                system memory rather than GPU or AGP memory. You should set this flag if you intend
                to read data back from the vertex buffer, because reading data from a buffer
                in the GPU or AGP memory is very expensive, and is in fact impossible if you
                specify HBU_WRITE_ONLY for the main buffer. If you use this option, all
                reads and writes will be done to the shadow buffer, and the shadow buffer will
                be synchronised with the real buffer at an appropriate time.
            */
            virtual HardwareVertexBufferSharedPtr createVertexBuffer( size_t vertexSize, size_t numVerts,
                                                                      HardwareBuffer::Usage usage,
                                                                      bool useShadowBuffer = false ) = 0;
            /** Create a hardware index buffer.
            @remarks Note that because buffers can be shared, they are reference
                counted so you do not need to worry about destroying them this will be done
                automatically.
            @param itype
                The type in index, either 16- or 32-bit, depending on how many vertices
                you need to be able to address
            @param numIndexes
                The number of indexes in the buffer
            @param usage
                One or more members of the HardwareBuffer::Usage enumeration.
            @param useShadowBuffer
                If set to @c true, this buffer will be 'shadowed' by one stored in
                system memory rather than GPU or AGP memory. You should set this flag if you intend
                to read data back from the index buffer, because reading data from a buffer
                in the GPU or AGP memory is very expensive, and is in fact impossible if you
                specify HBU_WRITE_ONLY for the main buffer. If you use this option, all
                reads and writes will be done to the shadow buffer, and the shadow buffer will
                be synchronised with the real buffer at an appropriate time.
            */
            virtual HardwareIndexBufferSharedPtr createIndexBuffer( HardwareIndexBuffer::IndexType itype,
                                                                    size_t                numIndexes,
                                                                    HardwareBuffer::Usage usage,
                                                                    bool useShadowBuffer = false ) = 0;

            /** Creates a new vertex declaration. */
            virtual VertexDeclaration *createVertexDeclaration();
            /** Destroys a vertex declaration. */
            virtual void destroyVertexDeclaration( VertexDeclaration *decl );

            /** Creates a new VertexBufferBinding. */
            virtual VertexBufferBinding *createVertexBufferBinding();
            /** Destroys a VertexBufferBinding. */
            virtual void destroyVertexBufferBinding( VertexBufferBinding *binding );

            /** Registers a vertex buffer as a copy of another.
            @remarks
                This is useful for registering an existing buffer as a temporary buffer
                which can be allocated just like a copy.
            */
            virtual void registerVertexBufferSourceAndCopy(
                const HardwareVertexBufferSharedPtr &sourceBuffer,
                const HardwareVertexBufferSharedPtr &copy );

            /** Allocates a copy of a given vertex buffer.
            @remarks
                This method allocates a temporary copy of an existing vertex buffer.
                This buffer is subsequently stored and can be made available for
                other purposes later without incurring the cost of construction /
                destruction.
            @param sourceBuffer
                The source buffer to use as a copy.
            @param licenseType
                The type of license required on this buffer - automatic
                release causes this class to release licenses every frame so that
                they can be reallocated anew.
            @param licensee
                Pointer back to the class requesting the copy, which must
                implement HardwareBufferLicense in order to be notified when the license
                expires.
            @param copyData
                If @c true, the current data is copied as well as the
                structure of the buffer/
            */
            virtual HardwareVertexBufferSharedPtr allocateVertexBufferCopy(
                const HardwareVertexBufferSharedPtr &sourceBuffer, BufferLicenseType licenseType,
                HardwareBufferLicensee *licensee, bool copyData = false );

            /** Manually release a vertex buffer copy for others to subsequently use.
            @remarks
                Only required if the original call to allocateVertexBufferCopy
                included a licenseType of BLT_MANUAL_RELEASE.
            @param bufferCopy
                The buffer copy. The caller is expected to delete
                or at least no longer use this reference, since another user may
                well begin to modify the contents of the buffer.
            */
            virtual void releaseVertexBufferCopy( const HardwareVertexBufferSharedPtr &bufferCopy );

            /** Tell engine that the vertex buffer copy intent to reuse.
            @remarks
                Ogre internal keep an expired delay counter of BLT_AUTOMATIC_RELEASE
                buffers, when the counter count down to zero, it'll release for other
                purposes later. But you can use this function to reset the counter to
                the internal configured value, keep the buffer not get released for
                some frames.
            @param bufferCopy
                The buffer copy. The caller is expected to keep this
                buffer copy for use.
            */
            virtual void touchVertexBufferCopy( const HardwareVertexBufferSharedPtr &bufferCopy );

            /** Free all unused vertex buffer copies.
            @remarks
                This method free all temporary vertex buffers that not in used.
                In normally, temporary vertex buffers are subsequently stored and can
                be made available for other purposes later without incurring the cost
                of construction / destruction. But in some cases you want to free them
                to save hardware memory (e.g. application was runs in a long time, you
                might free temporary buffers periodically to avoid memory overload).
            */
            virtual void _freeUnusedBufferCopies();

            /** Internal method for releasing all temporary buffers which have been
               allocated using BLT_AUTOMATIC_RELEASE; is called by OGRE.
            @param forceFreeUnused
                If @c true, free all unused temporary buffers.
                If @c false, auto detect and free all unused temporary buffers based on
                temporary buffers utilization.
            */
            virtual void _releaseBufferCopies( bool forceFreeUnused = false );

            /** Internal method that forces the release of copies of a given buffer.
            @remarks
                This usually means that the buffer which the copies are based on has
                been changed in some fundamental way, and the owner of the original
                wishes to make that known so that new copies will reflect the
                changes.
            @param sourceBuffer
                The source buffer as a shared pointer.  Any buffer copies created
                from the source buffer are deleted.
            */
            virtual void _forceReleaseBufferCopies( const HardwareVertexBufferSharedPtr &sourceBuffer );

            /** Internal method that forces the release of copies of a given buffer.
            @remarks
                This usually means that the buffer which the copies are based on has
                been changed in some fundamental way, and the owner of the original
                wishes to make that known so that new copies will reflect the
                changes.
            @param sourceBuffer
                The source buffer as a pointer. Any buffer copies created from
                the source buffer are deleted.
            */
            virtual void _forceReleaseBufferCopies( HardwareVertexBuffer *sourceBuffer );

            /// Notification that a hardware vertex buffer has been destroyed.
            void _notifyVertexBufferDestroyed( HardwareVertexBuffer *buf );
            /// Notification that a hardware index buffer has been destroyed.
            void _notifyIndexBufferDestroyed( HardwareIndexBuffer *buf );
        };

        /** Singleton wrapper for hardware buffer manager. */
        class _OgreExport HardwareBufferManager : public HardwareBufferManagerBase,
                                                  public Singleton<HardwareBufferManager>
        {
            friend class HardwareVertexBufferSharedPtr;
            friend class HardwareIndexBufferSharedPtr;

        protected:
            HardwareBufferManagerBase *mImpl;

        public:
            HardwareBufferManager( HardwareBufferManagerBase *imp );
            ~HardwareBufferManager() override;

            /** @copydoc HardwareBufferManagerBase::createVertexBuffer */
            HardwareVertexBufferSharedPtr createVertexBuffer( size_t vertexSize, size_t numVerts,
                                                              HardwareBuffer::Usage usage,
                                                              bool useShadowBuffer = false ) override
            {
                return mImpl->createVertexBuffer( vertexSize, numVerts, usage, useShadowBuffer );
            }
            /** @copydoc HardwareBufferManagerBase::createIndexBuffer */
            HardwareIndexBufferSharedPtr createIndexBuffer( HardwareIndexBuffer::IndexType itype,
                                                            size_t                         numIndexes,
                                                            HardwareBuffer::Usage          usage,
                                                            bool useShadowBuffer = false ) override
            {
                return mImpl->createIndexBuffer( itype, numIndexes, usage, useShadowBuffer );
            }

            /** @copydoc HardwareBufferManagerBase::createVertexDeclaration */
            VertexDeclaration *createVertexDeclaration() override
            {
                return mImpl->createVertexDeclaration();
            }
            /** @copydoc HardwareBufferManagerBase::destroyVertexDeclaration */
            void destroyVertexDeclaration( VertexDeclaration *decl ) override
            {
                mImpl->destroyVertexDeclaration( decl );
            }

            /** @copydoc HardwareBufferManagerBase::createVertexBufferBinding */
            VertexBufferBinding *createVertexBufferBinding() override
            {
                return mImpl->createVertexBufferBinding();
            }
            /** @copydoc HardwareBufferManagerBase::destroyVertexBufferBinding */
            void destroyVertexBufferBinding( VertexBufferBinding *binding ) override
            {
                mImpl->destroyVertexBufferBinding( binding );
            }
            /** @copydoc HardwareBufferManagerBase::registerVertexBufferSourceAndCopy */
            void registerVertexBufferSourceAndCopy( const HardwareVertexBufferSharedPtr &sourceBuffer,
                                                    const HardwareVertexBufferSharedPtr &copy ) override
            {
                mImpl->registerVertexBufferSourceAndCopy( sourceBuffer, copy );
            }
            /** @copydoc HardwareBufferManagerBase::allocateVertexBufferCopy */
            HardwareVertexBufferSharedPtr allocateVertexBufferCopy(
                const HardwareVertexBufferSharedPtr &sourceBuffer, BufferLicenseType licenseType,
                HardwareBufferLicensee *licensee, bool copyData = false ) override
            {
                return mImpl->allocateVertexBufferCopy( sourceBuffer, licenseType, licensee, copyData );
            }
            /** @copydoc HardwareBufferManagerBase::releaseVertexBufferCopy */
            void releaseVertexBufferCopy( const HardwareVertexBufferSharedPtr &bufferCopy ) override
            {
                mImpl->releaseVertexBufferCopy( bufferCopy );
            }

            /** @copydoc HardwareBufferManagerBase::touchVertexBufferCopy */
            void touchVertexBufferCopy( const HardwareVertexBufferSharedPtr &bufferCopy ) override
            {
                mImpl->touchVertexBufferCopy( bufferCopy );
            }

            /** @copydoc HardwareBufferManagerBase::_freeUnusedBufferCopies */
            void _freeUnusedBufferCopies() override { mImpl->_freeUnusedBufferCopies(); }
            /** @copydoc HardwareBufferManagerBase::_releaseBufferCopies */
            void _releaseBufferCopies( bool forceFreeUnused = false ) override
            {
                mImpl->_releaseBufferCopies( forceFreeUnused );
            }
            /** @copydoc HardwareBufferManagerBase::_forceReleaseBufferCopies */
            void _forceReleaseBufferCopies( const HardwareVertexBufferSharedPtr &sourceBuffer ) override
            {
                mImpl->_forceReleaseBufferCopies( sourceBuffer );
            }
            /** @copydoc HardwareBufferManagerBase::_forceReleaseBufferCopies */
            void _forceReleaseBufferCopies( HardwareVertexBuffer *sourceBuffer ) override
            {
                mImpl->_forceReleaseBufferCopies( sourceBuffer );
            }
            /** @copydoc HardwareBufferManagerBase::_notifyVertexBufferDestroyed */
            void _notifyVertexBufferDestroyed( HardwareVertexBuffer *buf )
            {
                mImpl->_notifyVertexBufferDestroyed( buf );
            }
            /** @copydoc HardwareBufferManagerBase::_notifyIndexBufferDestroyed */
            void _notifyIndexBufferDestroyed( HardwareIndexBuffer *buf )
            {
                mImpl->_notifyIndexBufferDestroyed( buf );
            }

            /** Override standard Singleton retrieval.
            @remarks
            Why do we do this? Well, it's because the Singleton
            implementation is in a .h file, which means it gets compiled
            into anybody who includes it. This is needed for the
            Singleton template to work, but we actually only want it
            compiled into the implementation of the class based on the
            Singleton, not all of them. If we don't change this, we get
            link errors when trying to use the Singleton-based class from
            an outside dll.
            @par
            This method just delegates to the template version anyway,
            but the implementation stays in this single compilation unit,
            preventing link errors.
            */
            static HardwareBufferManager &getSingleton();
            /** Override standard Singleton retrieval.
            @remarks
            Why do we do this? Well, it's because the Singleton
            implementation is in a .h file, which means it gets compiled
            into anybody who includes it. This is needed for the
            Singleton template to work, but we actually only want it
            compiled into the implementation of the class based on the
            Singleton, not all of them. If we don't change this, we get
            link errors when trying to use the Singleton-based class from
            an outside dll.
            @par
            This method just delegates to the template version anyway,
            but the implementation stays in this single compilation unit,
            preventing link errors.
            */
            static HardwareBufferManager *getSingletonPtr();
        };

        /** @} */
        /** @} */
    }  // namespace v1
}  // namespace Ogre

#include "OgreHeaderSuffix.h"

#endif  // __HardwareBufferManager__
