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Reimplemented eraseBlock for uncompressed blocks.

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This commit is contained in:
David Williams 2013-07-18 16:08:18 +02:00
parent 1e986f9aa6
commit 88cbeb309c
1 changed files with 74 additions and 2 deletions
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76
library/PolyVoxCore/include/PolyVoxCore/LargeVolume.inl
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@ -550,9 +550,10 @@ namespace PolyVox
template <typename VoxelType>
void LargeVolume<VoxelType>::eraseBlock(typename CompressedBlockMap::iterator itCompressedBlock) const
{
// Before deleting the block we may need to page out it's data. We
// only do this if the data has been modified since it was paged in.
CompressedBlock<VoxelType>* pCompressedBlock = itCompressedBlock->second;
// Before deleting the block we may need to page out its data. We
// only do this if the data has been modified since it was paged in.
if(pCompressedBlock->m_bDataModified)
{
// The position of the block within the volume.
@ -573,6 +574,77 @@ namespace PolyVox
template <typename VoxelType>
void LargeVolume<VoxelType>::eraseBlock(typename UncompressedBlockMap::iterator itUncompressedBlock) const
{
UncompressedBlock<VoxelType>* pUncompressedBlock = itUncompressedBlock->second;
// This should not often happen as blocks are normally deleted based on being least recently used.
// However, I can imagine that flushing a large number of blocks could cause this to occur. Just
// to be safe we handle it by invalidating the last accessed block pointer.
if(pUncompressedBlock == m_pLastAccessedBlock)
{
logWarning() << "The last accessed block is being erased from the uncompressed cache.";
m_pLastAccessedBlock = 0;
}
// Before deleting the block we may need to recompress its data. We
// only do this if the data has been modified since it was decompressed.
if(pUncompressedBlock->m_bDataModified)
{
// Get the compressed block which we will copy the data back in to.
Vector3DInt32 v3dBlockPos = itCompressedBlock->first;
CompressedBlock<VoxelType>* pCompressedBlock = getCompressedBlock(v3dBlockPos);
void* pSrcData = reinterpret_cast<void*>(pUncompressedBlock->m_tData);
uint32_t uSrcLength = m_uSideLength * m_uSideLength * m_uSideLength * sizeof(VoxelType);
uint8_t tempBuffer[10000];
void* pDstData = reinterpret_cast<void*>( tempBuffer );
uint32_t uDstLength = 10000;
uint32_t uCompressedLength = 0;
try
{
// Perform the compression
uCompressedLength = m_pCompressor->compress(pSrcData, uSrcLength, pDstData, uDstLength);
// Copy the resulting compressed data into the compressed block
pCompressedBlock->setData(pDstData, uDstLength);
}
catch(std::exception&)
{
// It is possible for the compression to fail. A common cause for this would be if the destination
// buffer is not big enough. So now we try again using a buffer that is definitely big enough.
// Note that ideally we will choose our earlier buffer size so that this almost never happens.
logWarning() << "The compressor failed to compress the block, proabaly due to the buffer being too small.";
logWarning() << "The compression will be tried again with a larger buffer";
uint32_t uMaxCompressedSize = m_pCompressor->getMaxCompressedSize(uSrcLength);
uint8_t* buffer = new uint8_t[ uMaxCompressedSize ];
pDstData = reinterpret_cast<void*>( buffer );
uDstLength = uMaxCompressedSize;
try
{
// Perform the compression
uCompressedLength = m_pCompressor->compress(pSrcData, uSrcLength, pDstData, uDstLength);
// Copy the resulting compressed data into the compressed block
pCompressedBlock->setData(pDstData, uDstLength);
}
catch(std::exception&)
{
// At this point it didn't work even with a bigger buffer.
// Not much more we can do so just rethrow the exception.
delete[] buffer;
POLYVOX_THROW(std::runtime_error, "Failed to compress block data");
}
delete[] buffer;
}
}
// We can now remove the block data from memory.
m_pUncompressedBlockCache.erase(itUncompressedBlock);
}
template <typename VoxelType>