# OgreHardwareBuffer.h

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    00001 /*
    00002 -----------------------------------------------------------------------------
    00003 This source file is part of OGRE
    00004     (Object-oriented Graphics Rendering Engine)
    00005 For the latest info, see http://www.ogre3d.org/
    00006
    00007 Copyright (c) 2000-2005 The OGRE Team
    00008 Also see acknowledgements in Readme.html
    00009
    00010 This program is free software; you can redistribute it and/or modify it under
    00011 the terms of the GNU Lesser General Public License as published by the Free Software
    00012 Foundation; either version 2 of the License, or (at your option) any later
    00013 version.
    00014
    00015 This program is distributed in the hope that it will be useful, but WITHOUT
    00016 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    00017 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
    00018
    00019 You should have received a copy of the GNU Lesser General Public License along with
    00020 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
    00021 Place - Suite 330, Boston, MA 02111-1307, USA, or go to
    00022 http://www.gnu.org/copyleft/lesser.txt.
    00023 -----------------------------------------------------------------------------
    00024 */
    00025 #ifndef __HardwareBuffer__
    00026 #define __HardwareBuffer__
    00027
    00028 // Precompiler options
    00029 #include "OgrePrerequisites.h"
    00030
    00031 namespace Ogre {
    00032
    00064     class _OgreExport HardwareBuffer
    00065     {
    00066
    00067         public:
    00069             enum Usage
    00070             {
    00074                 HBU_STATIC = 1,
    00080                 HBU_DYNAMIC = 2,
    00087                 HBU_WRITE_ONLY = 4,
    00096                 HBU_DISCARDABLE = 8,
    00098                 HBU_STATIC_WRITE_ONLY = 5,
    00104                 HBU_DYNAMIC_WRITE_ONLY = 6,
    00106                 HBU_DYNAMIC_WRITE_ONLY_DISCARDABLE = 14
    00107
    00108
    00109             };
    00111             enum LockOptions
    00112             {
    00114                 HBL_NORMAL,
    00119                 HBL_DISCARD,
    00123                 HBL_READ_ONLY,
    00127                 HBL_NO_OVERWRITE
    00128
    00129             };
    00130         protected:
    00131             size_t mSizeInBytes;
    00132             Usage mUsage;
    00133             bool mIsLocked;
    00134             size_t mLockStart;
    00135             size_t mLockSize;
    00136             bool mSystemMemory;
    00137             bool mUseShadowBuffer;
    00138             HardwareBuffer* mpShadowBuffer;
    00139             bool mShadowUpdated;
    00140             bool mSuppressHardwareUpdate;
    00141
    00143             virtual void* lockImpl(size_t offset, size_t length, LockOptions options) = 0;
    00145             virtual void unlockImpl(void) = 0;
    00146
    00147     public:
    00149             HardwareBuffer(Usage usage, bool systemMemory, bool useShadowBuffer)
    00150                 : mUsage(usage), mIsLocked(false), mSystemMemory(systemMemory),
    00151                 mUseShadowBuffer(useShadowBuffer), mpShadowBuffer(NULL), mShadowUpdated(false),
    00152                 mSuppressHardwareUpdate(false)
    00153             {
    00154                 // If use shadow buffer, upgrade to WRITE_ONLY on hardware side
    00155                 if (useShadowBuffer && usage == HBU_DYNAMIC)
    00156                 {
    00157                     mUsage = HBU_DYNAMIC_WRITE_ONLY;
    00158                 }
    00159                 else if (useShadowBuffer && usage == HBU_STATIC)
    00160                 {
    00161                     mUsage = HBU_STATIC_WRITE_ONLY;
    00162                 }
    00163             }
    00164             virtual ~HardwareBuffer() {}
    00171             virtual void* lock(size_t offset, size_t length, LockOptions options)
    00172             {
    00173                 assert(!isLocked() && "Cannot lock this buffer, it is already locked!");
    00174                 void* ret;
    00175                 if (mUseShadowBuffer)
    00176                 {
    00177                     if (options != HBL_READ_ONLY)
    00178                     {
    00179                         // we have to assume a read / write lock so we use the shadow buffer
    00180                         // and tag for sync on unlock()
    00181                         mShadowUpdated = true;
    00182                     }
    00183
    00184                     ret = mpShadowBuffer->lock(offset, length, options);
    00185                 }
    00186                 else
    00187                 {
    00188                     // Lock the real buffer if there is no shadow buffer
    00189                     ret = lockImpl(offset, length, options);
    00190                     mIsLocked = true;
    00191                 }
    00192                 mLockStart = offset;
    00193                 mLockSize = length;
    00194                 return ret;
    00195             }
    00196
    00201             void* lock(LockOptions options)
    00202             {
    00203                 return this->lock(0, mSizeInBytes, options);
    00204             }
    00217             virtual void unlock(void)
    00218             {
    00219                 assert(isLocked() && "Cannot unlock this buffer, it is not locked!");
    00220
    00221                 // If we used the shadow buffer this time...
    00222                 if (mUseShadowBuffer && mpShadowBuffer->isLocked())
    00223                 {
    00224                     mpShadowBuffer->unlock();
    00225                     // Potentially update the 'real' buffer from the shadow buffer
    00226                     _updateFromShadow();
    00227                 }
    00228                 else
    00229                 {
    00230                     // Otherwise, unlock the real one
    00231                     unlockImpl();
    00232                     mIsLocked = false;
    00233                 }
    00234
    00235             }
    00236
    00243             virtual void readData(size_t offset, size_t length, void* pDest) = 0;
    00252             virtual void writeData(size_t offset, size_t length, const void* pSource,
    00253                     bool discardWholeBuffer = false) = 0;
    00254
    00265             virtual void copyData(HardwareBuffer& srcBuffer, size_t srcOffset,
    00266                 size_t dstOffset, size_t length, bool discardWholeBuffer = false)
    00267             {
    00268                 const void *srcData = srcBuffer.lock(
    00269                     srcOffset, length, HBL_READ_ONLY);
    00270                 this->writeData(dstOffset, length, srcData, discardWholeBuffer);
    00271                 srcBuffer.unlock();
    00272             }
    00273
    00275             virtual void _updateFromShadow(void)
    00276             {
    00277                 if (mUseShadowBuffer && mShadowUpdated && !mSuppressHardwareUpdate)
    00278                 {
    00279                     // Do this manually to avoid locking problems
    00280                     const void *srcData = mpShadowBuffer->lockImpl(
    00281                         mLockStart, mLockSize, HBL_READ_ONLY);
    00282                     // Lock with discard if the whole buffer was locked, otherwise normal
    00283                     LockOptions lockOpt;
    00284                     if (mLockStart == 0 && mLockSize == mSizeInBytes)
    00285                         lockOpt = HBL_DISCARD;
    00286                     else
    00287                         lockOpt = HBL_NORMAL;
    00288
    00289                     void *destData = this->lockImpl(
    00290                         mLockStart, mLockSize, lockOpt);
    00291                     // Copy shadow to real
    00292                     memcpy(destData, srcData, mLockSize);
    00293                     this->unlockImpl();
    00294                     mpShadowBuffer->unlockImpl();
    00295                     mShadowUpdated = false;
    00296                 }
    00297             }
    00298
    00300             size_t getSizeInBytes(void) const { return mSizeInBytes; }
    00302             Usage getUsage(void) const { return mUsage; }
    00304             bool isSystemMemory(void) const { return mSystemMemory; }
    00306             bool hasShadowBuffer(void) const { return mUseShadowBuffer; }
    00308             bool isLocked(void) const {
    00309                 return mIsLocked || (mUseShadowBuffer && mpShadowBuffer->isLocked());
    00310             }
    00312             void suppressHardwareUpdate(bool suppress) {
    00313                 mSuppressHardwareUpdate = suppress;
    00314                 if (!suppress)
    00315                     _updateFromShadow();
    00316             }
    00317
    00318
    00319
    00320
    00321
    00322     };
    00323 }
    00324 #endif
    00325
    00326

Copyright © 2000-2005 by The OGRE Team
This work is licensed under a Creative Commons Attribution-ShareAlike 2.5 License.
Last modified Sun Feb 12 12:59:46 2006