llvertexbuffer.cpp

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#include "linden_common.h"

#include "llvertexbuffer.h"
// #include "llrender.h"
#include "llglheaders.h"
#include "llmemory.h"
#include "llmemtype.h"

//============================================================================

//static
S32 LLVertexBuffer::sCount = 0;
S32 LLVertexBuffer::sGLCount = 0;
BOOL LLVertexBuffer::sEnableVBOs = TRUE;
U32 LLVertexBuffer::sGLRenderBuffer = 0;
U32 LLVertexBuffer::sGLRenderIndices = 0;
U32 LLVertexBuffer::sLastMask = 0;
BOOL LLVertexBuffer::sVBOActive = FALSE;
BOOL LLVertexBuffer::sIBOActive = FALSE;
U32 LLVertexBuffer::sAllocatedBytes = 0;
BOOL LLVertexBuffer::sRenderActive = FALSE;

std::vector<U32> LLVertexBuffer::sDeleteList;
LLVertexBuffer::buffer_list_t LLVertexBuffer::sLockedList;

S32 LLVertexBuffer::sTypeOffsets[LLVertexBuffer::TYPE_MAX] =
{
        sizeof(LLVector3), // TYPE_VERTEX,
        sizeof(LLVector3), // TYPE_NORMAL,
        sizeof(LLVector2), // TYPE_TEXCOORD,
        sizeof(LLVector2), // TYPE_TEXCOORD2,
        sizeof(LLColor4U), // TYPE_COLOR,
        sizeof(LLVector3), // TYPE_BINORMAL,
        sizeof(F32),       // TYPE_WEIGHT,
        sizeof(LLVector4), // TYPE_CLOTHWEIGHT,
};

//static
void LLVertexBuffer::initClass(bool use_vbo)
{
        sEnableVBOs = use_vbo;
}

//static 
void LLVertexBuffer::unbind()
{
        if (sVBOActive)
        {
                glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
                sVBOActive = FALSE;
        }
        if (sIBOActive)
        {
                glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, 0);
                sIBOActive = FALSE;
        }

        sGLRenderBuffer = 0;
        sGLRenderIndices = 0;
}

//static
void LLVertexBuffer::cleanupClass()
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        sLockedList.clear();
        startRender(); 
        stopRender();
        clientCopy(); // deletes GL buffers
}

//static, call before rendering VBOs
void LLVertexBuffer::startRender()
{               
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        if (sEnableVBOs)
        {
                glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
                glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, 0);
                sVBOActive = FALSE;
                sIBOActive = FALSE;
        }
        
        sRenderActive = TRUE;
        sGLRenderBuffer = 0;
        sGLRenderIndices = 0;
        sLastMask = 0;
}

void LLVertexBuffer::stopRender()
{
        sRenderActive = FALSE;
}

void LLVertexBuffer::clientCopy(F64 max_time)
{
        if (!sDeleteList.empty())
        {
                size_t num = sDeleteList.size();
                glDeleteBuffersARB(sDeleteList.size(), (GLuint*) &(sDeleteList[0]));
                sDeleteList.clear();
                sGLCount -= num;
        }

        if (sEnableVBOs)
        {
                LLTimer timer;
                BOOL reset = TRUE;
                buffer_list_t::iterator iter = sLockedList.begin();
                while(iter != sLockedList.end())
                {
                        LLVertexBuffer* buffer = *iter;
                        if (buffer->isLocked() && buffer->useVBOs())
                        {
                                buffer->setBuffer(0);
                        }
                        ++iter;
                        if (reset)
                        {
                                reset = FALSE;
                                timer.reset(); //skip first copy (don't count pipeline stall)
                        }
                        else
                        {
                                if (timer.getElapsedTimeF64() > max_time)
                                {
                                        break;
                                }
                        }

                }

                sLockedList.erase(sLockedList.begin(), iter);
        }
}

//----------------------------------------------------------------------------

LLVertexBuffer::LLVertexBuffer(U32 typemask, S32 usage) :
        LLRefCount(),
        mNumVerts(0), mNumIndices(0), mUsage(usage), mGLBuffer(0), mGLIndices(0), 
        mMappedData(NULL),
        mMappedIndexData(NULL), mLocked(FALSE),
        mFinal(FALSE),
        mFilthy(FALSE),
        mEmpty(TRUE),
        mResized(FALSE)
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        if (!sEnableVBOs)
        {
                mUsage = GL_STREAM_DRAW_ARB;
        }
        
        S32 stride = 0;
        for (S32 i=0; i<TYPE_MAX; i++)
        {
                U32 mask = 1<<i;
                if (typemask & mask)
                {
                        mOffsets[i] = stride;
                        stride += sTypeOffsets[i];
                }
        }
        mTypeMask = typemask;
        mStride = stride;
        sCount++;
}

// protected, use unref()
//virtual
LLVertexBuffer::~LLVertexBuffer()
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        destroyGLBuffer();
        destroyGLIndices();
        sCount--;
        
        if (mLocked)
        {
                //pull off of locked list
                for (buffer_list_t::iterator i = sLockedList.begin(); i != sLockedList.end(); ++i)
                {
                        if (*i == this)
                        {
                                sLockedList.erase(i);
                                break;
                        }
                }
        }
};

//----------------------------------------------------------------------------

void LLVertexBuffer::createGLBuffer()
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);

        U32 size = getSize();
        if (mGLBuffer)
        {
                destroyGLBuffer();
        }

        if (size == 0)
        {
                return;
        }

        mMappedData = new U8[size];
        memset(mMappedData, 0, size);
        mEmpty = TRUE;

        if (useVBOs())
        {
                glGenBuffersARB(1, (GLuint*) &mGLBuffer);
                mResized = TRUE;
                sGLCount++;
        }
        else
        {
                static int gl_buffer_idx = 0;
                mGLBuffer = ++gl_buffer_idx;
        }
}

void LLVertexBuffer::createGLIndices()
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        U32 size = getIndicesSize();

        if (mGLIndices)
        {
                destroyGLIndices();
        }
        
        if (size == 0)
        {
                return;
        }

        mMappedIndexData = new U8[size];
        memset(mMappedIndexData, 0, size);
        mEmpty = TRUE;

        if (useVBOs())
        {
                glGenBuffersARB(1, (GLuint*) &mGLIndices);
                mResized = TRUE;
                sGLCount++;
        }
        else
        {
                static int gl_buffer_idx = 0;
                mGLIndices = ++gl_buffer_idx;
        }
}

void LLVertexBuffer::destroyGLBuffer()
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        if (mGLBuffer)
        {
                if (useVBOs())
                {
                        sDeleteList.push_back(mGLBuffer);
                }
                
                delete [] mMappedData;
                mMappedData = NULL;
                mEmpty = TRUE;
                sAllocatedBytes -= getSize();
        }
        
        mGLBuffer = 0;
}

void LLVertexBuffer::destroyGLIndices()
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        if (mGLIndices)
        {
                if (useVBOs())
                {
                        sDeleteList.push_back(mGLIndices);
                }
                
                delete [] mMappedIndexData;
                mMappedIndexData = NULL;
                mEmpty = TRUE;
                sAllocatedBytes -= getIndicesSize();
        }

        mGLIndices = 0;
}

void LLVertexBuffer::updateNumVerts(S32 nverts)
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        if (!mDynamicSize)
        {
                mNumVerts = nverts;
        }
        else if (mUsage == GL_STATIC_DRAW_ARB ||
                nverts > mNumVerts ||
                nverts < mNumVerts/2)
        {
                if (mUsage != GL_STATIC_DRAW_ARB)
                {
                        nverts += nverts/4;
                }

                mNumVerts = nverts;
        }
}

void LLVertexBuffer::updateNumIndices(S32 nindices)
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        if (!mDynamicSize)
        {
                mNumIndices = nindices;
        }
        else if (mUsage == GL_STATIC_DRAW_ARB ||
                nindices > mNumIndices ||
                nindices < mNumIndices/2)
        {
                if (mUsage != GL_STATIC_DRAW_ARB)
                {
                        nindices += nindices/4;
                }

                mNumIndices = nindices;
        }
}

void LLVertexBuffer::makeStatic()
{
        if (!sEnableVBOs)
        {
                return;
        }
        
        if (sRenderActive)
        {
                llerrs << "Make static called during render." << llendl;
        }
        
        if (mUsage != GL_STATIC_DRAW_ARB)
        {
                if (useVBOs())
                {
                        if (mGLBuffer)
                        {
                                sDeleteList.push_back(mGLBuffer);
                        }
                        if (mGLIndices)
                        {
                                sDeleteList.push_back(mGLIndices);
                        }
                }
        
                if (mGLBuffer)
                {
                        sGLCount++;
                        glGenBuffersARB(1, (GLuint*) &mGLBuffer);
                }
                if (mGLIndices)
                {
                        sGLCount++;
                        glGenBuffersARB(1, (GLuint*) &mGLIndices);
                }
                        
                mUsage = GL_STATIC_DRAW_ARB;
                mResized = TRUE;

                if (!mLocked)
                {
                        mLocked = TRUE;
                        sLockedList.push_back(this);
                }
        }
}

void LLVertexBuffer::allocateBuffer(S32 nverts, S32 nindices, bool create)
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
                
        updateNumVerts(nverts);
        updateNumIndices(nindices);
        
        if (mMappedData)
        {
                llerrs << "LLVertexBuffer::allocateBuffer() called redundantly." << llendl;
        }
        if (create && (nverts || nindices))
        {
                createGLBuffer();
                createGLIndices();
        }
        
        sAllocatedBytes += getSize() + getIndicesSize();
}

void LLVertexBuffer::resizeBuffer(S32 newnverts, S32 newnindices)
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        mDynamicSize = TRUE;
        if (mUsage == GL_STATIC_DRAW_ARB)
        { //always delete/allocate static buffers on resize
                destroyGLBuffer();
                destroyGLIndices();
                allocateBuffer(newnverts, newnindices, TRUE);
                mFinal = FALSE;
        }
        else if (newnverts > mNumVerts || newnindices > mNumIndices ||
                         newnverts < mNumVerts/2 || newnindices < mNumIndices/2)
        {
                sAllocatedBytes -= getSize() + getIndicesSize();
                
                S32 oldsize = getSize();
                S32 old_index_size = getIndicesSize();

                updateNumVerts(newnverts);              
                updateNumIndices(newnindices);
                
                S32 newsize = getSize();
                S32 new_index_size = getIndicesSize();

                sAllocatedBytes += newsize + new_index_size;

                if (newsize)
                {
                        if (!mGLBuffer)
                        { //no buffer exists, create a new one
                                createGLBuffer();
                        }
                        else
                        {
                                //delete old buffer, keep GL buffer for now
                                U8* old = mMappedData;
                                mMappedData = new U8[newsize];
                                if (old)
                                {       
                                        memcpy(mMappedData, old, llmin(newsize, oldsize));
                                        if (newsize > oldsize)
                                        {
                                                memset(mMappedData+oldsize, 0, newsize-oldsize);
                                        }

                                        delete [] old;
                                }
                                else
                                {
                                        memset(mMappedData, 0, newsize);
                                        mEmpty = TRUE;
                                }
                                mResized = TRUE;
                        }
                }
                else if (mGLBuffer)
                {
                        destroyGLBuffer();
                }
                
                if (new_index_size)
                {
                        if (!mGLIndices)
                        {
                                createGLIndices();
                        }
                        else
                        {
                                //delete old buffer, keep GL buffer for now
                                U8* old = mMappedIndexData;
                                mMappedIndexData = new U8[new_index_size];
                                if (old)
                                {       
                                        memcpy(mMappedIndexData, old, llmin(new_index_size, old_index_size));
                                        if (new_index_size > old_index_size)
                                        {
                                                memset(mMappedIndexData+old_index_size, 0, new_index_size - old_index_size);
                                        }
                                        delete [] old;
                                }
                                else
                                {
                                        memset(mMappedIndexData, 0, new_index_size);
                                        mEmpty = TRUE;
                                }
                                mResized = TRUE;
                        }
                }
                else if (mGLIndices)
                {
                        destroyGLIndices();
                }
        }
}

BOOL LLVertexBuffer::useVBOs() const
{
        //it's generally ineffective to use VBO for things that are streaming
        //when we already have a client buffer around
        if (mUsage == GL_STREAM_DRAW_ARB)
        {
                return FALSE;
        }

        return sEnableVBOs && (!sRenderActive || !mLocked);
}

//----------------------------------------------------------------------------

// Map for data access
U8* LLVertexBuffer::mapBuffer(S32 access)
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        if (sRenderActive)
        {
                llwarns << "Buffer mapped during render frame!" << llendl;
        }
        if (!mGLBuffer && !mGLIndices)
        {
                llerrs << "LLVertexBuffer::mapBuffer() called  before createGLBuffer" << llendl;
        }
        if (mFinal)
        {
                llerrs << "LLVertexBuffer::mapBuffer() called on a finalized buffer." << llendl;
        }
        if (!mMappedData && !mMappedIndexData)
        {
                llerrs << "LLVertexBuffer::mapBuffer() called on unallocated buffer." << llendl;
        }
        
        if (!mLocked && useVBOs())
        {
                mLocked = TRUE;
                sLockedList.push_back(this);
        }
        
        return mMappedData;
}

void LLVertexBuffer::unmapBuffer()
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        if (mMappedData || mMappedIndexData)
        {
                if (useVBOs() && mLocked)
                {
                        if (mGLBuffer)
                        {
                                if (mResized)
                                {
                                        glBufferDataARB(GL_ARRAY_BUFFER_ARB, getSize(), mMappedData, mUsage);
                                }
                                else
                                {
                                        if (mEmpty || mDirtyRegions.empty())
                                        {
                                                glBufferSubDataARB(GL_ARRAY_BUFFER_ARB, 0, getSize(), mMappedData);
                                        }
                                        else
                                        {
                                                for (std::vector<DirtyRegion>::iterator i = mDirtyRegions.begin(); i != mDirtyRegions.end(); ++i)
                                                {
                                                        DirtyRegion& region = *i;
                                                        glBufferSubDataARB(GL_ARRAY_BUFFER_ARB, region.mIndex*mStride, region.mCount*mStride, mMappedData + region.mIndex*mStride);
                                                }
                                        }
                                }
                        }
                        
                        if (mGLIndices)
                        {
                                if (mResized)
                                {
                                        glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB, getIndicesSize(), mMappedIndexData, mUsage);
                                }
                                else
                                {
                                        if (mEmpty || mDirtyRegions.empty())
                                        {
                                                glBufferSubDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB, 0, getIndicesSize(), mMappedIndexData);
                                        }
                                        else
                                        {
                                                for (std::vector<DirtyRegion>::iterator i = mDirtyRegions.begin(); i != mDirtyRegions.end(); ++i)
                                                {
                                                        DirtyRegion& region = *i;
                                                        glBufferSubDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB, region.mIndicesIndex*sizeof(U32), 
                                                                region.mIndicesCount*sizeof(U32), mMappedIndexData + region.mIndicesIndex*sizeof(U32));
                                                }
                                        }
                                }
                        }

                        mDirtyRegions.clear();
                        mFilthy = FALSE;
                        mResized = FALSE;

                        if (mUsage == GL_STATIC_DRAW_ARB)
                        { //static draw buffers can only be mapped a single time
                                //throw out client data (we won't be using it again)
                                delete [] mMappedData;
                                delete [] mMappedIndexData;
                                mMappedIndexData = NULL;
                                mMappedData = NULL;
                                mEmpty = TRUE;
                                mFinal = TRUE;
                        }
                        else
                        {
                                mEmpty = FALSE;
                        }
                        
                        mLocked = FALSE;
                        
                        glFlush();
                }
        }
}

//----------------------------------------------------------------------------

template <class T,S32 type> struct VertexBufferStrider
{
        typedef LLStrider<T> strider_t;
        static bool get(LLVertexBuffer& vbo, 
                                        strider_t& strider, 
                                        S32 index)
        {
                vbo.mapBuffer();
                if (type == LLVertexBuffer::TYPE_INDEX)
                {
                        S32 stride = sizeof(T);
                        strider = (T*)(vbo.getMappedIndices() + index*stride);
                        strider.setStride(0);
                        return TRUE;
                }
                else if (vbo.hasDataType(type))
                {
                        S32 stride = vbo.getStride();
                        strider = (T*)(vbo.getMappedData() + vbo.getOffset(type) + index*stride);
                        strider.setStride(stride);
                        return TRUE;
                }
                else
                {
                        llerrs << "VertexBufferStrider could not find valid vertex data." << llendl;
                }
                return FALSE;
        }
};


bool LLVertexBuffer::getVertexStrider(LLStrider<LLVector3>& strider, S32 index)
{
        return VertexBufferStrider<LLVector3,TYPE_VERTEX>::get(*this, strider, index);
}
bool LLVertexBuffer::getIndexStrider(LLStrider<U32>& strider, S32 index)
{
        return VertexBufferStrider<U32,TYPE_INDEX>::get(*this, strider, index);
}
bool LLVertexBuffer::getTexCoordStrider(LLStrider<LLVector2>& strider, S32 index)
{
        return VertexBufferStrider<LLVector2,TYPE_TEXCOORD>::get(*this, strider, index);
}
bool LLVertexBuffer::getTexCoord2Strider(LLStrider<LLVector2>& strider, S32 index)
{
        return VertexBufferStrider<LLVector2,TYPE_TEXCOORD2>::get(*this, strider, index);
}
bool LLVertexBuffer::getNormalStrider(LLStrider<LLVector3>& strider, S32 index)
{
        return VertexBufferStrider<LLVector3,TYPE_NORMAL>::get(*this, strider, index);
}
bool LLVertexBuffer::getBinormalStrider(LLStrider<LLVector3>& strider, S32 index)
{
        return VertexBufferStrider<LLVector3,TYPE_BINORMAL>::get(*this, strider, index);
}
bool LLVertexBuffer::getColorStrider(LLStrider<LLColor4U>& strider, S32 index)
{
        return VertexBufferStrider<LLColor4U,TYPE_COLOR>::get(*this, strider, index);
}
bool LLVertexBuffer::getWeightStrider(LLStrider<F32>& strider, S32 index)
{
        return VertexBufferStrider<F32,TYPE_WEIGHT>::get(*this, strider, index);
}
bool LLVertexBuffer::getClothWeightStrider(LLStrider<LLVector4>& strider, S32 index)
{
        return VertexBufferStrider<LLVector4,TYPE_CLOTHWEIGHT>::get(*this, strider, index);
}

void LLVertexBuffer::setStride(S32 type, S32 new_stride)
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        if (mNumVerts)
        {
                llerrs << "LLVertexBuffer::setOffset called with mNumVerts = " << mNumVerts << llendl;
        }
        // This code assumes that setStride() will only be called once per VBO per type.
        S32 delta = new_stride - sTypeOffsets[type];
        for (S32 i=type+1; i<TYPE_MAX; i++)
        {
                if (mTypeMask & (1<<i))
                {
                        mOffsets[i] += delta;
                }
        }
        mStride += delta;
}

//----------------------------------------------------------------------------

// Set for rendering
void LLVertexBuffer::setBuffer(U32 data_mask)
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        //set up pointers if the data mask is different ...
        BOOL setup = (sLastMask != data_mask);

        if (useVBOs())
        {
                if (mGLBuffer && (mGLBuffer != sGLRenderBuffer || !sVBOActive))
                {
                        glBindBufferARB(GL_ARRAY_BUFFER_ARB, mGLBuffer);
                        sVBOActive = TRUE;
                        setup = TRUE; // ... or the bound buffer changed
                }
                if (mGLIndices && (mGLIndices != sGLRenderIndices || !sIBOActive))
                {
                        glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, mGLIndices);
                        sIBOActive = TRUE;
                }
                
                unmapBuffer();
        }
        else
        {               
                if (mGLBuffer)
                {
                        if (sEnableVBOs && sVBOActive)
                        {
                                glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
                                sVBOActive = FALSE;
                                setup = TRUE; // ... or a VBO is deactivated
                        }
                        if (sGLRenderBuffer != mGLBuffer)
                        {
                                setup = TRUE; // ... or a client memory pointer changed
                        }
                }
                if (sEnableVBOs && mGLIndices && sIBOActive)
                {
                        glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, 0);
                        sIBOActive = FALSE;
                }
        }
        
        if (mGLIndices)
        {
                sGLRenderIndices = mGLIndices;
        }
        if (mGLBuffer)
        {
                sGLRenderBuffer = mGLBuffer;
                if (data_mask && setup)
                {
                        if (!sRenderActive)
                        {
                                llwarns << "Vertex buffer set for rendering outside of render frame." << llendl;
                        }
                        setupVertexBuffer(data_mask); // subclass specific setup (virtual function)
                        sLastMask = data_mask;
                }
        }
}

// virtual (default)
void LLVertexBuffer::setupVertexBuffer(U32 data_mask) const
{
        LLMemType mt(LLMemType::MTYPE_VERTEX_DATA);
        stop_glerror();
        U8* base = useVBOs() ? NULL : mMappedData;
        S32 stride = mStride;

        if ((data_mask & mTypeMask) != data_mask)
        {
                llerrs << "LLVertexBuffer::setupVertexBuffer missing required components for supplied data mask." << llendl;
        }

        if (data_mask & MAP_VERTEX)
        {
                glVertexPointer(3,GL_FLOAT, stride, (void*)(base + 0));
        }
        if (data_mask & MAP_NORMAL)
        {
                glNormalPointer(GL_FLOAT, stride, (void*)(base + mOffsets[TYPE_NORMAL]));
        }
        if (data_mask & MAP_TEXCOORD2)
        {
                glClientActiveTextureARB(GL_TEXTURE1_ARB);
                glTexCoordPointer(2,GL_FLOAT, stride, (void*)(base + mOffsets[TYPE_TEXCOORD2]));
        }
        if (data_mask & MAP_TEXCOORD)
        {
                glClientActiveTextureARB(GL_TEXTURE0_ARB);
                glTexCoordPointer(2,GL_FLOAT, stride, (void*)(base + mOffsets[TYPE_TEXCOORD]));
        }
        if (data_mask & MAP_COLOR)
        {
                glColorPointer(4, GL_UNSIGNED_BYTE, stride, (void*)(base + mOffsets[TYPE_COLOR]));
        }
        if (data_mask & MAP_BINORMAL)
        {
                glVertexAttribPointerARB(6, 3, GL_FLOAT, FALSE,  stride, (void*)(base + mOffsets[TYPE_BINORMAL]));
        }
        if (data_mask & MAP_WEIGHT)
        {
                glVertexAttribPointerARB(1, 1, GL_FLOAT, FALSE, stride, (void*)(base + mOffsets[TYPE_WEIGHT]));
        }
        if (data_mask & MAP_CLOTHWEIGHT)
        {
                glVertexAttribPointerARB(4, 4, GL_FLOAT, TRUE,  stride, (void*)(base + mOffsets[TYPE_CLOTHWEIGHT]));
        }

        llglassertok();
}

void LLVertexBuffer::markDirty(U32 vert_index, U32 vert_count, U32 indices_index, U32 indices_count)
{
        if (useVBOs() && !mFilthy)
        {
                if (!mDirtyRegions.empty())
                {
                        DirtyRegion& region = *(mDirtyRegions.rbegin());
                        
                        if (region.mIndex+region.mCount > vert_index)
                        {
                                //this buffer has received multiple updates since the last copy, mark it filthy
                                mFilthy = TRUE;
                                mDirtyRegions.clear();
                                return;
                        }
                        
                        if (region.mIndex + region.mCount == vert_index &&
                                region.mIndicesIndex + region.mIndicesCount == indices_index)
                        {
                                region.mCount += vert_count;
                                region.mIndicesCount += indices_count;
                                return;
                        }
                }

                mDirtyRegions.push_back(DirtyRegion(vert_index,vert_count,indices_index,indices_count));
        }
}

void LLVertexBuffer::markClean()
{
        if (!mResized && !mEmpty && !mFilthy)
        {
                buffer_list_t::reverse_iterator iter = sLockedList.rbegin();
                if (*iter == this)
                {
                        mLocked = FALSE;
                        sLockedList.pop_back();
                }
        }
}

---