ocrm.bsky.social
the game where you go into mines and start crafting! but for consoles (forked directly from smartcmd's github)
1#pragma once
2#include "xmcore.h"
3
4// 4J added - Storage for block & sky light data. Lighting data is normally stored as 4-bits per tile, in a DataLayer class of 16384 bytes ( 128 x 16 x 16 x 0.5 )
5// This class provides more economical storage for such data by taking into consideration that it is quite common for large parts of the lighting data in a level to
6// be very compressible (large amounts of 0 for block lights, 0 and 15 for sky lights).
7// We are aiming here to balance performance (lighting data is accessed very frequently) against size.
8
9// Details of storage method:
10
11// 1. Lighting is split into horizontal planes, of which there are 128, and each taking up 128 bytes (16 x 16 x 0.5)
12// 2. Each of these layers has a permanently allocated index in this class (planeIndices).
13// 3. Data for allocatedPlaneCount planes worth of data is allocated in the data array ( allocatedPlaneCount * 128 bytes )
14// 4. If a plane index for a layer is < 128, then the data for that layer is at data[ index * 128 ]
15// 5. If a plane index for a layer is 128, then all values for that plane are 0
16// 6. If a plane index for a layer is 129, then all values for that plane are 15
17
18// This class needs to be thread safe as there are times where chunk (and light) data are shared between server & main threads. Light values are queried
19// very regularly so this needs to be as light-weight as possible.
20
21// To meet these requirements, this class is now implemented using a lock-free system, implemented using a read-copy-update (RCU) type algorithm. Some details...
22
23// (1) The storage details for the class are now packed into a single __int64, which contains both a pointer to the data that is required and a count of how many planes worth
24// of storage are allocated. This allows the full storage to be updated atomically using compare and exchange operations (implemented with InterlockedCompareExchangeRelease64).
25// (2) The data pointer referenced in this __int64 points to an area of memory which is 128 + 128 * plane_count bytes long, where the first 128 bytes stoere the plane indices, and
26// the rest of the data is variable in size to accomodate however many planes are required to be stored
27// (3) The RCU bit of the algorithm means that any read operations don't need to do any checks or locks at all. When the data needs to be updated, a copy of it is made and updated,
28// then an attempt is made to swap the new data in - if this succeeds then the old data pointer is deleted later at some point where we know nothing will be reading from it anymore.
29// This is achieved by putting the delete request in a queue which means it won't actually get deleted until 2 game ticks after the last time its reference existed, which should give
30// us a large margin of safety. If the attempt to swap the new data in fails, then the whole write operation has to be attempted again - this is the only time there is really a
31// high cost for this algorithm and such write collisions should be rare.
32
33//#define LIGHT_COMPRESSION_STATS
34class TileCompressData_SPU;
35
36class SparseLightStorage
37{
38 friend class TileCompressData_SPU;
39private:
40// unsigned char planeIndices[128];
41 __int64 dataAndCount; // Contains packed-together data pointer (lower 48-bits), and count of lines used (upper 16-bits)
42
43// unsigned char *data;
44// unsigned int allocatedPlaneCount;
45
46 static const int ALL_0_INDEX = 128;
47 static const int ALL_15_INDEX = 129;
48#ifdef _XBOX
49 static const unsigned int MM_PHYSICAL_4KB_BASE = 0xE0000000; // Start of where 4KB page sized physical allocations are made
50#endif
51public:
52 SparseLightStorage(bool sky);
53 SparseLightStorage(bool sky, bool isUpper);
54 SparseLightStorage(SparseLightStorage *copyFrom); // ctor with deep copy
55 ~SparseLightStorage();
56
57 void setData(byteArray dataIn, unsigned int inOffset); // Set all lighting values from a data array of length 16384 (128 x 16 x 16 x 0.5).
58 void getData(byteArray retArray, unsigned int retOffset); // Gets all lighting values into an array of length 16384.
59 int get(int x, int y, int z); // Get an individual lighting value
60 void set(int x, int y, int z, int val); // Set an individual lighting value
61 void setAllBright(); // Set all lighting values to fully bright
62 int setDataRegion(byteArray dataIn, int x0, int y0, int z0, int x1, int y1, int z1, int offset); // Sets a region of lighting values with the data at offset position in the array dataIn - external ordering compatible with java DataLayer
63 int getDataRegion(byteArray dataInOut, int x0, int y0, int z0, int x1, int y1, int z1, int offset); // Updates the data at offset position dataInOut with a region of lighting information - external ordering compatible with java DataLayer
64
65 static void staticCtor();
66
67 void addNewPlane(int y);
68 void getPlaneIndicesAndData(unsigned char **planeIndices, unsigned char **data);
69 void updateDataAndCount(__int64 newDataAndCount);
70 int compress();
71
72 bool isCompressed();
73 void queueForDelete(unsigned char *data);
74
75 static void tick();
76 static int deleteQueueIndex;
77 static XLockFreeStack <unsigned char> deleteQueue[3];
78
79
80#ifdef LIGHT_COMPRESSION_STATS
81 int count;
82#endif
83
84 void write(DataOutputStream *dos);
85 void read(DataInputStream *dis);
86};
87