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Revert "Decided to always use a 64-bit chunk key, rather than trying to make it configurable."

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This reverts commit 69f6f4ac3713e7a9eee804773a516cc5c3412183.
This commit is contained in:
David Williams 2015-03-21 14:40:57 +01:00
parent ceeb8f70ce
commit 92eaaae765
3 changed files with 19 additions and 17 deletions
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2
include/PolyVox/Impl/Config.h
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@ -36,4 +36,6 @@ freely, subject to the following restrictions:
//#define POLYVOX_ASSERTS_ENABLED
#define POLYVOX_THROW_ENABLED
typedef int32_t PagedVolumeChunkKeyIntType;
#endif

24
include/PolyVox/PagedVolume.h
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@ -284,17 +284,17 @@ namespace PolyVox
struct ChunkKey
{
ChunkKey(int32_t x, int32_t y, int32_t z) : iZPos(z), iYPos(y), iXPos(x), iValid(~0) {}
int64_t iZPos : 10;
int64_t iYPos : 10;
int64_t iXPos : 10;
PagedVolumeChunkKeyIntType iZPos : 10;
PagedVolumeChunkKeyIntType iYPos : 10;
PagedVolumeChunkKeyIntType iXPos : 10;
// Should only be true when the last access chunk pointer is valid,
// so we don't need to have a seperate check for that before using it.
int64_t iValid : 2;
PagedVolumeChunkKeyIntType iValid : 2;
};
static_assert(sizeof(ChunkKey) == sizeof(int64_t), "");
static_assert(sizeof(ChunkKey) == sizeof(PagedVolumeChunkKeyIntType), "");
int64_t posToChunkKey(int32_t iXPos, int32_t iYPos, int32_t iZPos) const
PagedVolumeChunkKeyIntType posToChunkKey(int32_t iXPos, int32_t iYPos, int32_t iZPos) const
{
iXPos = iXPos >> m_uChunkSideLengthPower;
iYPos = iYPos >> m_uChunkSideLengthPower;
@ -306,22 +306,22 @@ namespace PolyVox
// In general, bit shifting signed integers is dubious because of potential undefined or implementation defied behaviour.
// However, it seems that in practice most compilers and architectures work in the same way (http://stackoverflow.com/a/6488645).
static_assert((int64_t(-3) / 4) == 0, "fdfs");
static_assert((int64_t(-3) >> 2) == -1, "fdfs");
static_assert((int32_t(-3) / 4) == 0, "fdfs");
static_assert((int32_t(-3) >> 2) == -1, "fdfs");
/*chunkKey.iXPos = iXPos;
chunkKey.iYPos = iYPos;
chunkKey.iZPos = iZPos;*/
// If this kind of casting ever causes problems there are
// other solutions here: http://stackoverflow.com/a/2468738
int64_t iKeyAsInt64 = force_cast<int64_t>(chunkKey);
PagedVolumeChunkKeyIntType iKeyAsInt32 = force_cast<PagedVolumeChunkKeyIntType>(chunkKey);
return iKeyAsInt64;
return iKeyAsInt32;
}
Chunk* getChunk(int64_t iKeyAsInt32) const;
Chunk* getChunk(PagedVolumeChunkKeyIntType iKeyAsInt32) const;
mutable int64_t m_v3dLastAccessedChunkKey = 0;
mutable PagedVolumeChunkKeyIntType m_v3dLastAccessedChunkKey = 0;
mutable Chunk* m_pLastAccessedChunk = nullptr;
mutable std::unordered_map<uint32_t, std::unique_ptr< Chunk > > m_mapChunks;

10
include/PolyVox/PagedVolume.inl
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@ -115,7 +115,7 @@ namespace PolyVox
template <typename VoxelType>
VoxelType PagedVolume<VoxelType>::getVoxel(int32_t uXPos, int32_t uYPos, int32_t uZPos) const
{
const int64_t key = posToChunkKey(uXPos, uYPos, uZPos);
const PagedVolumeChunkKeyIntType key = posToChunkKey(uXPos, uYPos, uZPos);
// Only call get chunk if we can't reuse the chunk pointer from the last voxel access.
auto pChunk = (key == m_v3dLastAccessedChunkKey) ? m_pLastAccessedChunk : getChunk(key);
@ -147,7 +147,7 @@ namespace PolyVox
template <typename VoxelType>
void PagedVolume<VoxelType>::setVoxel(int32_t uXPos, int32_t uYPos, int32_t uZPos, VoxelType tValue)
{
const int64_t key = posToChunkKey(uXPos, uYPos, uZPos);
const PagedVolumeChunkKeyIntType key = posToChunkKey(uXPos, uYPos, uZPos);
// Only call get chunk if we can't reuse the chunk pointer from the last voxel access.
auto pChunk = (key == m_v3dLastAccessedChunkKey) ? m_pLastAccessedChunk : getChunk(key);
@ -202,7 +202,7 @@ namespace PolyVox
{
for(int32_t z = v3dStart.getZ(); z <= v3dEnd.getZ(); z++)
{
const int64_t key = posToChunkKey(x, y, z);
const PagedVolumeChunkKeyIntType key = posToChunkKey(x, y, z);
// Note that we don't check against the last chunk here. We're
// not accessing the voxels, we just want to pull them into memory.
@ -256,7 +256,7 @@ namespace PolyVox
{
for(int32_t z = v3dStart.getZ(); z <= v3dEnd.getZ(); z++)
{
const int64_t key = posToChunkKey(x, y, z);
const PagedVolumeChunkKeyIntType key = posToChunkKey(x, y, z);
m_mapChunks.erase(key);
}
}
@ -264,7 +264,7 @@ namespace PolyVox
}
template <typename VoxelType>
typename PagedVolume<VoxelType>::Chunk* PagedVolume<VoxelType>::getChunk(int64_t iKeyAsInt32) const
typename PagedVolume<VoxelType>::Chunk* PagedVolume<VoxelType>::getChunk(PagedVolumeChunkKeyIntType iKeyAsInt32) const
{
// This function is relatively large and slow because it involves searching for a chunk and creating it if it is not found. A natural
// optimization is to only do this work if the chunk we are accessing is not the same as the last chunk we accessed (which it usually