AnotherFoxGuy/polyvox
1
0
Fork 0
Code Issues Pull Requests Activity

Merge branch 'feature/optimize-paged-volume' into develop

Browse Source
This commit is contained in:
David Williams 2015-03-21 16:30:07 +01:00
commit 6516c00e62
8 changed files with 65 additions and 127 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
CMakeLists.txt
View File

@ -37,6 +37,10 @@ IF(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang") #Maybe "OR
ADD_DEFINITIONS(-std=c++0x) #Enable C++0x mode
ENDIF()
IF(CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
ADD_DEFINITIONS(-D_CRT_SECURE_NO_WARNINGS)
ENDIF()
ADD_SUBDIRECTORY(include)
OPTION(ENABLE_EXAMPLES "Should the examples be built" ON)

4
examples/OpenGL/Shapes.cpp
View File

@ -57,8 +57,8 @@ void createSphereInVolume(RawVolume<MaterialDensityPair88>& volData, float fRadi
void createCubeInVolume(RawVolume<MaterialDensityPair88>& volData, Vector3DInt32 lowerCorner, Vector3DInt32 upperCorner, uint8_t uValue)
{
uint8_t maxDen = MaterialDensityPair88::getMaxDensity();
uint8_t minDen = MaterialDensityPair88::getMinDensity();
uint8_t maxDen = static_cast<uint8_t>(MaterialDensityPair88::getMaxDensity());
uint8_t minDen = static_cast<uint8_t>(MaterialDensityPair88::getMinDensity());
//This three-level for loop iterates over every voxel between the specified corners
for (int z = lowerCorner.getZ(); z <= upperCorner.getZ(); z++)
{

34
include/PolyVox/PagedVolume.h
View File

@ -281,32 +281,22 @@ namespace PolyVox
PagedVolume& operator=(const PagedVolume& rhs);
private:
std::shared_ptr<Chunk> getChunk(int32_t uChunkX, int32_t uChunkY, int32_t uChunkZ) const;
bool canReuseLastAccessedChunk(int32_t iChunkX, int32_t iChunkY, int32_t iChunkZ) const;
Chunk* getChunk(int32_t uChunkX, int32_t uChunkY, int32_t uChunkZ) const;
void purgeNullPtrsFromAllChunks(void) const;
// Storing these properties individually has proved to be faster than keeping
// them in a Vector3DInt32 as it avoids constructions and comparison overheads.
// They are also at the start of the class in the hope that they will be pulled
// into cache - I've got no idea if this actually makes a difference.
mutable int32_t m_v3dLastAccessedChunkX = 0;
mutable int32_t m_v3dLastAccessedChunkY = 0;
mutable int32_t m_v3dLastAccessedChunkZ = 0;
mutable Chunk* m_pLastAccessedChunk = nullptr;
// The chunk data is stored in the pair of maps below. This will often hold the same set of chunks but there are occasions
// when they can differ (more on that in a moment). The main store is the set of 'recently used chunks' which holds shared_ptr's
// to the chunk data. When memory is low chunks can be removed from this list and, assuming there are no more references to
// them, they will be deleted. However, it is also possible that a Sampler is pointing at a given chunk, and in this case the
// reference counting will ensure that the chunk survives until the sampler has finished with it.
//
// However, this leaves us open to a subtle bug. If a chunk is removed from the recently used set, continues to exist due to a
// sampler using it, and then the user tries to access it through the volume interface, then the volume will page the chunk
// back in (not knowing the sampler still has it). This would result in two chunks in memory with the same position is space.
// To avoid this, the 'all chunks' set tracks chunks with are used by the volume *and/or* the samplers. It holds weak pointers
// so does not cause chunks to persist.
//
// TODO: Do we really need maps here? It means we are storing the chunk positions in the map, but they are also stored in the
// chunks themselves (so they can be passed to the pager from the chunks destructor). Can we use a set here? What is a better approach?
typedef std::unordered_map<Vector3DInt32, std::weak_ptr< Chunk > > WeakPtrChunkMap;
mutable WeakPtrChunkMap m_pAllChunks;
typedef std::unordered_map<Vector3DInt32, std::shared_ptr< Chunk > > SharedPtrChunkMap;
mutable SharedPtrChunkMap m_pRecentlyUsedChunks;
mutable std::unordered_map<Vector3DInt32, std::unique_ptr< Chunk > > m_mapChunks;
mutable uint32_t m_uTimestamper = 0;
mutable Vector3DInt32 m_v3dLastAccessedChunkPos = Vector3DInt32(0, 0, 0); //There are no invalid positions, but initially the m_pLastAccessedChunk pointer will be null
mutable std::shared_ptr<Chunk> m_pLastAccessedChunk = nullptr;
uint32_t m_uChunkCountLimit = 0;
// The size of the volume

128
include/PolyVox/PagedVolume.inl
View File

@ -123,7 +123,8 @@ namespace PolyVox
const uint16_t yOffset = static_cast<uint16_t>(uYPos & m_iChunkMask);
const uint16_t zOffset = static_cast<uint16_t>(uZPos & m_iChunkMask);
auto pChunk = getChunk(chunkX, chunkY, chunkZ);
auto pChunk = canReuseLastAccessedChunk(chunkX, chunkY, chunkZ) ? m_pLastAccessedChunk : getChunk(chunkX, chunkY, chunkZ);
return pChunk->getVoxel(xOffset, yOffset, zOffset);
}
@ -155,7 +156,8 @@ namespace PolyVox
const uint16_t yOffset = static_cast<uint16_t>(uYPos - (chunkY << m_uChunkSideLengthPower));
const uint16_t zOffset = static_cast<uint16_t>(uZPos - (chunkZ << m_uChunkSideLengthPower));
auto pChunk = getChunk(chunkX, chunkY, chunkZ);
auto pChunk = canReuseLastAccessedChunk(chunkX, chunkY, chunkZ) ? m_pLastAccessedChunk : getChunk(chunkX, chunkY, chunkZ);
pChunk->setVoxel(xOffset, yOffset, zOffset, tValue);
}
@ -214,17 +216,11 @@ namespace PolyVox
template <typename VoxelType>
void PagedVolume<VoxelType>::flushAll()
{
// Clear this pointer so it doesn't hang on to any chunks.
// Clear this pointer as all chunks are about to be removed.
m_pLastAccessedChunk = nullptr;
// Erase all the most recently used chunks.
m_pRecentlyUsedChunks.clear();
// Remove deleted chunks from the list of all loaded chunks.
purgeNullPtrsFromAllChunks();
// If there are still some chunks left then this is a cause for concern. Perhaps samplers are holding on to them?
POLYVOX_LOG_WARNING_IF(m_pAllChunks.size() > 0, "Chunks still exist after performing flushAll()! Perhaps you have samplers attached?");
m_mapChunks.clear();
}
////////////////////////////////////////////////////////////////////////////////
@ -233,7 +229,7 @@ namespace PolyVox
template <typename VoxelType>
void PagedVolume<VoxelType>::flush(Region regFlush)
{
// Clear this pointer so it doesn't hang on to any chunks.
// Clear this pointer in case the chunk it points at is flushed.
m_pLastAccessedChunk = nullptr;
// Convert the start and end positions into chunk space coordinates
@ -256,79 +252,52 @@ namespace PolyVox
{
for(int32_t z = v3dStart.getZ(); z <= v3dEnd.getZ(); z++)
{
m_pRecentlyUsedChunks.erase(Vector3DInt32(x, y, z));
m_mapChunks.erase(Vector3DInt32(x, y, z));
}
}
}
m_pLastAccessedChunk = nullptr;
// We might now have so null pointers in the 'all chunks' list so clean them up.
purgeNullPtrsFromAllChunks();
}
template <typename VoxelType>
std::shared_ptr<typename PagedVolume<VoxelType>::Chunk> PagedVolume<VoxelType>::getChunk(int32_t uChunkX, int32_t uChunkY, int32_t uChunkZ) const
bool PagedVolume<VoxelType>::canReuseLastAccessedChunk(int32_t iChunkX, int32_t iChunkY, int32_t iChunkZ) const
{
return ((iChunkX == m_v3dLastAccessedChunkX) &&
(iChunkY == m_v3dLastAccessedChunkY) &&
(iChunkZ == m_v3dLastAccessedChunkZ) &&
(m_pLastAccessedChunk));
}
template <typename VoxelType>
typename PagedVolume<VoxelType>::Chunk* PagedVolume<VoxelType>::getChunk(int32_t uChunkX, int32_t uChunkY, int32_t uChunkZ) const
{
Vector3DInt32 v3dChunkPos(uChunkX, uChunkY, uChunkZ);
//Check if we have the same chunk as last time, if so there's no need to even update
//the time stamp. If we updated it everytime then that would be every time we touched
//a voxel, which would overflow a uint32_t and require us to use a uint64_t instead.
//This check should also provide a significant speed boost as usually it is true.
if((v3dChunkPos == m_v3dLastAccessedChunkPos) && (m_pLastAccessedChunk != 0))
{
return m_pLastAccessedChunk;
}
// The chunk was not the same as last time, but we can now hope it is in the set of most recently used chunks.
std::shared_ptr<typename PagedVolume<VoxelType>::Chunk> pChunk = nullptr;
typename SharedPtrChunkMap::iterator itChunk = m_pRecentlyUsedChunks.find(v3dChunkPos);
Chunk* pChunk = nullptr;
auto itChunk = m_mapChunks.find(v3dChunkPos);
// Check whether the chunk was found.
if ((itChunk) != m_pRecentlyUsedChunks.end())
if ((itChunk) != m_mapChunks.end())
{
// The chunk was found so we can use it.
pChunk = itChunk->second;
pChunk = itChunk->second.get();
POLYVOX_ASSERT(pChunk, "Recent chunk list shold never contain a null pointer.");
}
if (!pChunk)
{
// Although it's not in our recently use chunks, there's some (slim) chance that it
// exists in the list of all loaded chunks, because a sampler may be holding on to it.
typename WeakPtrChunkMap::iterator itWeakChunk = m_pAllChunks.find(v3dChunkPos);
if (itWeakChunk != m_pAllChunks.end())
{
// We've found an entry in the 'all chunks' list, but it can be null. This happens if a sampler was the
// last thing to be keeping it alive and then the sampler let it go. In this case we remove it from the
// list, and it will get added again soon when we page it in and fill it with valid data.
if (itWeakChunk->second.expired())
{
m_pAllChunks.erase(itWeakChunk);
}
else
{
// The chunk is valid. We know it's not in the recently used list (we checked earlier) so it should be added.
pChunk = std::shared_ptr< PagedVolume<VoxelType>::Chunk >(itWeakChunk->second);
m_pRecentlyUsedChunks.insert(std::make_pair(v3dChunkPos, pChunk));
}
}
}
// If we still haven't found the chunk then it's time to create a new one and page it in from disk.
if (!pChunk)
{
// The chunk was not found so we will create a new one.
pChunk = std::make_shared< PagedVolume<VoxelType>::Chunk >(v3dChunkPos, m_uChunkSideLength, m_pPager);
pChunk = new PagedVolume<VoxelType>::Chunk(v3dChunkPos, m_uChunkSideLength, m_pPager);
pChunk->m_uChunkLastAccessed = ++m_uTimestamper; // Important, as we may soon delete the oldest chunk
m_mapChunks.insert(std::make_pair(v3dChunkPos, std::unique_ptr<Chunk>(pChunk)));
// As we are loading a new chunk we should try to ensure we don't go over our target memory usage.
bool erasedChunk = false;
while (m_pRecentlyUsedChunks.size() + 1 > m_uChunkCountLimit) // +1 ready for new chunk we will add next.
while (m_mapChunks.size() > m_uChunkCountLimit)
{
// Find the least recently used chunk. Hopefully this isn't too slow.
typename SharedPtrChunkMap::iterator itUnloadChunk = m_pRecentlyUsedChunks.begin();
for (typename SharedPtrChunkMap::iterator i = m_pRecentlyUsedChunks.begin(); i != m_pRecentlyUsedChunks.end(); i++)
auto itUnloadChunk = m_mapChunks.begin();
for (auto i = m_mapChunks.begin(); i != m_mapChunks.end(); i++)
{
if (i->second->m_uChunkLastAccessed < itUnloadChunk->second->m_uChunkLastAccessed)
{
@ -337,25 +306,15 @@ namespace PolyVox
}
// Erase the least recently used chunk
m_pRecentlyUsedChunks.erase(itUnloadChunk);
erasedChunk = true;
m_mapChunks.erase(itUnloadChunk);
}
// If we've deleted any chunks from the recently used list then this
// seems like a good place to purge the 'all chunks' list as well.
if (erasedChunk)
{
purgeNullPtrsFromAllChunks();
}
// Add our new chunk to the maps.
m_pAllChunks.insert(std::make_pair(v3dChunkPos, pChunk));
m_pRecentlyUsedChunks.insert(std::make_pair(v3dChunkPos, pChunk));
}
pChunk->m_uChunkLastAccessed = ++m_uTimestamper;
m_pLastAccessedChunk = pChunk;
m_v3dLastAccessedChunkPos = v3dChunkPos;
//m_v3dLastAccessedChunkPos = v3dChunkPos;
m_v3dLastAccessedChunkX = uChunkX;
m_v3dLastAccessedChunkY = uChunkY;
m_v3dLastAccessedChunkZ = uChunkZ;
return pChunk;
}
@ -366,28 +325,9 @@ namespace PolyVox
template <typename VoxelType>
uint32_t PagedVolume<VoxelType>::calculateSizeInBytes(void)
{
// Purge null chunks so we know that all chunks are used.
purgeNullPtrsFromAllChunks();
// Note: We disregard the size of the other class members as they are likely to be very small compared to the size of the
// allocated voxel data. This also keeps the reported size as a power of two, which makes other memory calculations easier.
return PagedVolume<VoxelType>::Chunk::calculateSizeInBytes(m_uChunkSideLength) * m_pAllChunks.size();
}
template <typename VoxelType>
void PagedVolume<VoxelType>::purgeNullPtrsFromAllChunks(void) const
{
for (auto chunkIter = m_pAllChunks.begin(); chunkIter != m_pAllChunks.end();)
{
if (chunkIter->second.expired())
{
chunkIter = m_pAllChunks.erase(chunkIter);
}
else
{
chunkIter++;
}
}
return PagedVolume<VoxelType>::Chunk::calculateSizeInBytes(m_uChunkSideLength) * m_mapChunks.size();
}
}

3
include/PolyVox/PagedVolumeSampler.inl
View File

@ -110,7 +110,8 @@ namespace PolyVox
uYPosInChunk * this->mVolume->m_uChunkSideLength +
uZPosInChunk * this->mVolume->m_uChunkSideLength * this->mVolume->m_uChunkSideLength;
auto pCurrentChunk = this->mVolume->getChunk(uXChunk, uYChunk, uZChunk);
auto pCurrentChunk = this->mVolume->canReuseLastAccessedChunk(uXChunk, uYChunk, uZChunk) ?
this->mVolume->m_pLastAccessedChunk : this->mVolume->getChunk(uXChunk, uYChunk, uZChunk);
mCurrentVoxel = pCurrentChunk->m_tData + uVoxelIndexInChunk;
}

2
include/PolyVox/Vector.h
View File

@ -29,10 +29,12 @@ freely, subject to the following restrictions:
#include "PolyVoxForwardDeclarations.h"
#include <algorithm>
#include <cmath>
#include <cstring>
#include <functional>
#include <iostream>
#include <memory>
namespace PolyVox
{

5
include/PolyVox/Vector.inl
View File

@ -39,10 +39,7 @@ namespace PolyVox
template <uint32_t Size,typename StorageType, typename OperationType>
Vector<Size,StorageType,OperationType>::Vector(StorageType tFillValue)
{
for(uint32_t ct = 0; ct < Size; ct++)
{
m_tElements[ct] = tFillValue;
}
std::fill(m_tElements, m_tElements + Size, tFillValue);
}
/**

8
tests/TestVolumeSubclass.cpp
View File

@ -73,7 +73,9 @@ public:
/// Gets a voxel at the position given by <tt>x,y,z</tt> coordinates
VoxelType getVoxel(int32_t uXPos, int32_t uYPos, int32_t uZPos) const
{
if ((uXPos < mVolumeData.getDimension(0)) && (uYPos < mVolumeData.getDimension(1)) && (uZPos < mVolumeData.getDimension(2)))
if ((uXPos >= 0) && (uXPos < static_cast<int32_t>(mVolumeData.getDimension(0))) &&
(uYPos >= 0) && (uYPos < static_cast<int32_t>(mVolumeData.getDimension(1))) &&
(uZPos >= 0) && (uZPos < static_cast<int32_t>(mVolumeData.getDimension(2))))
{
return mVolumeData(uXPos, uYPos, uZPos);
}
@ -94,7 +96,9 @@ public:
/// Sets the voxel at the position given by <tt>x,y,z</tt> coordinates
bool setVoxel(int32_t uXPos, int32_t uYPos, int32_t uZPos, VoxelType tValue)
{
if ((uXPos < mVolumeData.getDimension(0)) && (uYPos < mVolumeData.getDimension(1)) && (uZPos < mVolumeData.getDimension(2)))
if( (uXPos >= 0) && (uXPos < static_cast<int32_t>(mVolumeData.getDimension(0))) &&
(uYPos >= 0) && (uYPos < static_cast<int32_t>(mVolumeData.getDimension(1))) &&
(uZPos >= 0) && (uZPos < static_cast<int32_t>(mVolumeData.getDimension(2))))
{
mVolumeData(uXPos, uYPos, uZPos) = tValue;
return true;