diff options
| -rw-r--r-- | src/database.cpp | 39 | ||||
| -rw-r--r-- | src/database.h | 2 |
2 files changed, 31 insertions, 10 deletions
diff --git a/src/database.cpp b/src/database.cpp index 15579a7f0..26f6992fc 100644 --- a/src/database.cpp +++ b/src/database.cpp @@ -20,6 +20,14 @@ with this program; if not, write to the Free Software Foundation, Inc., #include "database.h" #include "irrlichttypes.h" + +/**************** + * Black magic! * + **************** + * The position hashing is very messed up. + * It's a lot more complicated than it looks. + */ + static inline s16 unsigned_to_signed(u16 i, u16 max_positive) { if (i < max_positive) { @@ -30,19 +38,32 @@ static inline s16 unsigned_to_signed(u16 i, u16 max_positive) } +// Modulo of a negative number does not work consistently in C +static inline s64 pythonmodulo(s64 i, s16 mod) +{ + if (i >= 0) { + return i % mod; + } + return mod - ((-i) % mod); +} + + s64 Database::getBlockAsInteger(const v3s16 pos) const { - return (((u64) pos.Z) << 24) + - (((u64) pos.Y) << 12) + - ((u64) pos.X); + return (u64) pos.Z * 0x1000000 + + (u64) pos.Y * 0x1000 + + (u64) pos.X; } -v3s16 Database::getIntegerAsBlock(const s64 i) const + +v3s16 Database::getIntegerAsBlock(s64 i) const { - v3s16 pos; - pos.Z = unsigned_to_signed((i >> 24) & 0xFFF, 0x1000 / 2); - pos.Y = unsigned_to_signed((i >> 12) & 0xFFF, 0x1000 / 2); - pos.X = unsigned_to_signed((i ) & 0xFFF, 0x1000 / 2); - return pos; + v3s16 pos; + pos.X = unsigned_to_signed(pythonmodulo(i, 4096), 2048); + i = (i - pos.X) / 4096; + pos.Y = unsigned_to_signed(pythonmodulo(i, 4096), 2048); + i = (i - pos.Y) / 4096; + pos.Z = unsigned_to_signed(pythonmodulo(i, 4096), 2048); + return pos; } diff --git a/src/database.h b/src/database.h index a86861379..f009877d2 100644 --- a/src/database.h +++ b/src/database.h @@ -35,7 +35,7 @@ public: virtual void saveBlock(MapBlock *block)=0; virtual MapBlock* loadBlock(v3s16 blockpos)=0; s64 getBlockAsInteger(const v3s16 pos) const; - v3s16 getIntegerAsBlock(const s64 i) const; + v3s16 getIntegerAsBlock(s64 i) const; virtual void listAllLoadableBlocks(std::list<v3s16> &dst)=0; virtual int Initialized(void)=0; virtual ~Database() {}; |