4jcraft/Minecraft.World/Level/Storage/SparseLightStorage.cpp

#include "../../Platform/stdafx.h"
#include "SparseLightStorage.h"

// Note: See header for an overview of this class

int SparseLightStorage::deleteQueueIndex;
XLockFreeStack<unsigned char> SparseLightStorage::deleteQueue[3];

void SparseLightStorage::staticCtor() {
    for (int i = 0; i < 3; i++) {
        deleteQueue[i].Initialize();
    }
}

// Initialise lighting storage, with very limited compression - the very first
// plane is stored as either compressed to be "all 15" or "all 0" depending on
// whether this will store sky or not, and the rest of the planes aren't
// compressed at all. The reason behind this is to keep the total allocation as
// a round number of 4K (small) pages, ie 16K. By doing this, and doing this
// "special" allocation as a XPhysicalAlloc rather than a malloc, we can help
// ensure that this full allocation gets cleaned up properly when the first
// proper compression is done on this storage. If it were just allocated with
// malloc, then the memory management system would have a large number of 16512
// allocations to free, and it seems from experimentation that these basically
// don't make it back to the system as free pages. Note - the other approach
// here would be to allocate *no* actual storage for the lights at the ctor
// stage. However, as chunks are created then this creates an awful lot of
// intermediate stages as each line of lighting is added, so it is actually much
// cleaner to just allocate almost fully here & then attempt to do a single
// compression pass over the data later on.
SparseLightStorage::SparseLightStorage(bool sky) {
    // Allocate using physical alloc. As this will (by default) return memory
    // from the pool of 4KB pages, the address will in the range of
    // MM_PHYSICAL_4KB_BASE upwards. We can use this fact to identify the
    // allocation later, and so free it with the corresponding call to
    // XPhysicalFree.
#ifdef _XBOX
    unsigned char* planeIndices = (unsigned char*)XPhysicalAlloc(
        128 * 128, MAXULONG_PTR, 4096, PAGE_READWRITE);
#else
    unsigned char* planeIndices = (unsigned char*)malloc(128 * 128);
#endif
    unsigned char* data = planeIndices + 128;
    planeIndices[127] = sky ? ALL_15_INDEX : ALL_0_INDEX;
    for (int i = 0; i < 127; i++) {
        planeIndices[i] = i;
    }
    XMemSet(data, 0, 128 * 127);

    // Data and count packs together the pointer to our data and the count of
    // planes allocated - 127 planes allocated in this case

    dataAndCount =
        0x007F000000000000L | (((int64_t)planeIndices) & 0x0000ffffffffffffL);

#ifdef LIGHT_COMPRESSION_STATS
    count = 127;
#endif
}

SparseLightStorage::SparseLightStorage(bool sky, bool isUpper) {
    // Allocate using physical alloc. As this will (by default) return memory
    // from the pool of 4KB pages, the address will in the range of
    // MM_PHYSICAL_4KB_BASE upwards. We can use this fact to identify the
    // allocation later, and so free it with the corresponding call to
    // XPhysicalFree.
    unsigned char* planeIndices = (unsigned char*)malloc(128);
    for (int i = 0; i < 128; i++) {
        planeIndices[i] = sky ? ALL_15_INDEX : ALL_0_INDEX;
    }

    // Data and count packs together the pointer to our data and the count of
    // planes allocated - 0 planes allocated in this case

    dataAndCount =
        0x0000000000000000L | (((int64_t)planeIndices) & 0x0000ffffffffffffL);

#ifdef LIGHT_COMPRESSION_STATS
    count = 0;
#endif
}

SparseLightStorage::~SparseLightStorage() {
    unsigned char* indicesAndData =
        (unsigned char*)(dataAndCount & 0x0000ffffffffffff);
    // Determine correct means to free this data - could have been allocated
    // either with XPhysicalAlloc or malloc

#ifdef _XBOX
    if ((unsigned int)indicesAndData >= MM_PHYSICAL_4KB_BASE) {
        XPhysicalFree(indicesAndData);
    } else
#endif
    {
        free(indicesAndData);
    }
    //	printf("Free (in dtor) 0x%x\n", indicesAndData);
}

SparseLightStorage::SparseLightStorage(SparseLightStorage* copyFrom) {
    // Extra details of source storage
    int64_t sourceDataAndCount = copyFrom->dataAndCount;
    unsigned char* sourceIndicesAndData =
        (unsigned char*)(sourceDataAndCount & 0x0000ffffffffffff);
    int sourceCount = (sourceDataAndCount >> 48) & 0xffff;

    // Allocate & copy indices ( 128 bytes ) and any allocated planes (128 *
    // count)
    unsigned char* destIndicesAndData =
        (unsigned char*)malloc(sourceCount * 128 + 128);

    // AP - I've moved this to be before the memcpy because of a very strange
    // bug on vita. Sometimes dataAndCount wasn't valid in time when ::get was
    // called. This should never happen and this isn't a proper solution but
    // fixes it for now.

    dataAndCount = (sourceDataAndCount & 0xffff000000000000L) |
                   (((int64_t)destIndicesAndData) & 0x0000ffffffffffffL);

    XMemCpy(destIndicesAndData, sourceIndicesAndData, sourceCount * 128 + 128);

#ifdef LIGHT_COMPRESSION_STATS
    count = sourceCount;
#endif
}

// Set all lighting values from a data array of length 16384 (128 x 16 x 16 x
// 0.5). Source data must have same order as original java game
void SparseLightStorage::setData(byteArray dataIn, unsigned int inOffset) {
    //  Original order is defined as:
    //  pos = (x << 11 | z << 7 | y);
    //  slot = pos >> 1;
    //  part = pos & 1;
    //  if ( part == 0 ) value = data[slot] & 0xf
    //  else value = (data[slot] >> 4) & 0xf

    // Two passed through the data. First pass sets up plane indices, and counts
    // number of planes that we actually need to allocate
    int allocatedPlaneCount = 0;
    unsigned char _planeIndices[128];

    for (int y = 0; y < 128; y++) {
        bool all0 = true;
        bool all15 = true;

        for (int xz = 0; xz < 256;
             xz++)  // 256 in loop as 16 x 16 separate bytes need checked
        {
            int pos = (xz << 7) | y;
            int slot = pos >> 1;
            int part = pos & 1;
            unsigned char value = (dataIn[slot + inOffset] >> (part * 4)) & 15;
            if (value != 0) all0 = false;
            if (value != 15) all15 = false;
        }
        if (all0) {
            _planeIndices[y] = ALL_0_INDEX;
        } else if (all15) {
            _planeIndices[y] = ALL_15_INDEX;
        } else {
            _planeIndices[y] = allocatedPlaneCount++;
        }
    }

    // Allocate required storage
    unsigned char* planeIndices =
        (unsigned char*)malloc(128 * allocatedPlaneCount + 128);
    unsigned char* data = planeIndices + 128;
    XMemCpy(planeIndices, _planeIndices, 128);

    // Second pass through to actually copy the data in to the storage allocated
    // for the required planes
    unsigned char* pucOut = data;
    for (int y = 0; y < 128; y++) {
        // Index will be < 128 if we allocated storage for it and it has a valid
        // index. No need to actually check the index as we know they were
        // sequentially allocated above.
        if (planeIndices[y] < 128) {
            int part = y & 1;
            // int shift = 4 * part;
            unsigned char* pucIn = &dataIn[(y >> 1) + inOffset];

            for (int xz = 0; xz < 128;
                 xz++)  // 128 ( 16 x 16 x 0.5 ) in loop as packing 2 values
                        // into each destination byte
            {
                *pucOut = ((*pucIn) >> (part * 4)) & 15;
                pucIn += 64;

                *pucOut |= (((*pucIn) >> (part * 4)) & 15) << 4;
                pucIn += 64;
                pucOut++;
            }
        }
    }

    // Get new data and count packed info

    int64_t newDataAndCount = ((int64_t)planeIndices) & 0x0000ffffffffffffL;

    newDataAndCount |= ((int64_t)allocatedPlaneCount) << 48;

    updateDataAndCount(newDataAndCount);
}

// Gets all lighting values into an array of length 16384. Destination data will
// have same order as original java game.
void SparseLightStorage::getData(byteArray retArray, unsigned int retOffset) {
    XMemSet(retArray.data + retOffset, 0, 16384);
    unsigned char *planeIndices, *data;
    getPlaneIndicesAndData(&planeIndices, &data);

    //  Original order is defined as:
    //  pos = (x << 11 | z << 7 | y);
    //  slot = pos >> 1;
    //  part = pos & 1;
    //  if ( part == 0 ) value = data[slot] & 0xf
    //  else value = (data[slot] >> 4) & 0xf

    for (int y = 0; y < 128; y++) {
        if (planeIndices[y] == ALL_0_INDEX) {
            // No need to do anything in this case as retArray is initialised to
            // zero
        } else if (planeIndices[y] == ALL_15_INDEX) {
            int part = y & 1;
            unsigned char value = 15 << (part * 4);
            unsigned char* pucOut = &retArray.data[(y >> 1) + retOffset];
            for (int xz = 0; xz < 256; xz++) {
                *pucOut |= value;
                pucOut += 64;
            }
        } else {
            int part = y & 1;
            int shift = 4 * part;
            unsigned char* pucOut = &retArray.data[(y >> 1) + retOffset];
            unsigned char* pucIn = &data[planeIndices[y] * 128];
            for (int xz = 0; xz < 128;
                 xz++)  // 128 in loop (16 x 16 x 0.5) as input data is being
                        // treated in pairs of nybbles that are packed in the
                        // same byte
            {
                unsigned char value = (*pucIn) & 15;
                *pucOut |= (value << shift);
                pucOut += 64;

                value = ((*pucIn) >> 4) & 15;
                *pucOut |= (value << shift);
                pucOut += 64;

                pucIn++;
            }
        }
    }
}

// Get an individual lighting value
int SparseLightStorage::get(int x, int y, int z) {
    unsigned char *planeIndices, *data;
    getPlaneIndicesAndData(&planeIndices, &data);

    if (planeIndices[y] == ALL_0_INDEX) {
        return 0;
    } else if (planeIndices[y] == ALL_15_INDEX) {
        return 15;
    } else {
        int planeIndex = x * 16 + z;  // Index within this xz plane
        int byteIndex =
            planeIndex /
            2;  // Byte index within the plane (2 tiles stored per byte)
        int shift = (planeIndex & 1) * 4;  // Bit shift within the byte
        int retval = (data[planeIndices[y] * 128 + byteIndex] >> shift) & 15;

        return retval;
    }
}

// Set an individual lighting value
void SparseLightStorage::set(int x, int y, int z, int val) {
    unsigned char *planeIndices, *data;
    getPlaneIndicesAndData(&planeIndices, &data);

    // If this plane isn't yet allocated, then we might have some extra work to
    // do
    if (planeIndices[y] >= ALL_0_INDEX) {
        // No data allocated. Early out though if we are storing what is already
        // represented by our special index.
        if ((val == 0) && (planeIndices[y] == ALL_0_INDEX)) {
            return;
        }
        if ((val == 15) && (planeIndices[y] == ALL_15_INDEX)) {
            return;
        }

        // Reallocate the storage for planes to accomodate one extra
        addNewPlane(y);

        // Get pointers again as these may have moved
        getPlaneIndicesAndData(&planeIndices, &data);
    }

    // Either data was already allocated, or we've just done that. Now store our
    // value into the right place.

    int planeIndex = x * 16 + z;  // Index within this xz plane
    int byteIndex = planeIndex /
                    2;  // Byte index within the plane (2 tiles stored per byte)
    int shift = (planeIndex & 1) * 4;  // Bit shift within the byte
    int mask = 0xf0 >> shift;

    int idx = planeIndices[y] * 128 + byteIndex;
    data[idx] = (data[idx] & mask) | (val << shift);
}

void SparseLightStorage::setAllBright() {
    unsigned char* planeIndices = (unsigned char*)malloc(128);
    for (int i = 0; i < 128; i++) {
        planeIndices[i] = ALL_15_INDEX;
    }
    // Data and count packs together the pointer to our data and the count of
    // planes allocated, which is currently zero

    int64_t newDataAndCount = ((int64_t)planeIndices) & 0x0000ffffffffffffL;

    updateDataAndCount(newDataAndCount);
}

// Sets a region of lighting values with the data at offset position in the
// array dataIn - external ordering compatible with java DataLayer Note - when
// data was extracted from the original data layers by
// LevelChunk::getBlocksAndData, y0 had to have even alignment and y1 - y0 also
// needed to be even as data was packed in nyblles in this dimension, and the
// code didn't make any attempt to unpack it. This behaviour is copied here for
// compatibility even though our source data isn't packed this way. Returns size
// of data copied.
int SparseLightStorage::setDataRegion(byteArray dataIn, int x0, int y0, int z0,
                                      int x1, int y1, int z1, int offset) {
    // Actual setting of data happens when calling set method so no need to lock
    // here
    unsigned char* pucIn = &dataIn.data[offset];
    for (int x = x0; x < x1; x++) {
        for (int z = z0; z < z1; z++) {
            // Emulate how data was extracted from DataLayer... see comment
            // above
            int yy0 = y0 & 0xfffffffe;
            int len = (y1 - y0) / 2;
            for (int i = 0; i < len; i++) {
                int y = yy0 + (i * 2);

                set(x, y, z, (*pucIn) & 15);
                set(x, y + 1, z, ((*pucIn) >> 4) & 15);
                pucIn++;
            }
        }
    }
    ptrdiff_t count = pucIn - &dataIn.data[offset];

    return (int)count;
}

// Updates the data at offset position dataInOut with a region of lighting
// information - external ordering compatible with java DataLayer Note - when
// data was placed in the original data layers by LevelChunk::setBlocksAndData,
// y0 had to have even alignment and y1 - y0 also needed to be even as data was
// packed in nyblles in this dimension, and the code didn't make any attempt to
// unpack it. This behaviour is copied here for compatibility even though our
// source data isn't packed this way Returns size of data copied.
int SparseLightStorage::getDataRegion(byteArray dataInOut, int x0, int y0,
                                      int z0, int x1, int y1, int z1,
                                      int offset) {
    unsigned char* pucOut = &dataInOut.data[offset];
    for (int x = x0; x < x1; x++) {
        for (int z = z0; z < z1; z++) {
            // Emulate how data was extracted from DataLayer... see comment
            // above
            int yy0 = y0 & 0xfffffffe;
            int len = (y1 - y0) / 2;
            for (int i = 0; i < len; i++) {
                int y = yy0 + (i * 2);

                *pucOut = get(x, y, z);
                *pucOut |= get(x, y + 1, z) << 4;
                pucOut++;
            }
        }
    }
    ptrdiff_t count = pucOut - &dataInOut.data[offset];

    return (int)count;
}

void SparseLightStorage::addNewPlane(int y) {
    bool success = false;
    do {
        // Get last packed data pointer & count
        int64_t lastDataAndCount = dataAndCount;

        // Unpack count & data pointer
        int lastLinesUsed = (int)((lastDataAndCount >> 48) & 0xffff);
        unsigned char* lastDataPointer =
            (unsigned char*)(lastDataAndCount & 0x0000ffffffffffff);

        // Find out what to prefill the newly allocated line with
        unsigned char planeIndex = lastDataPointer[y];
        int prefill = 0;
        if (planeIndex < ALL_0_INDEX)
            return;  // Something has already allocated this line - we're done
        else if (planeIndex == ALL_15_INDEX)
            prefill = 255;

        int linesUsed = lastLinesUsed + 1;

        // Allocate new memory storage, copy over anything from old storage, and
        // initialise remainder
        unsigned char* dataPointer =
            (unsigned char*)malloc(linesUsed * 128 + 128);
        XMemCpy(dataPointer, lastDataPointer, 128 * lastLinesUsed + 128);
        XMemSet(dataPointer + (128 * lastLinesUsed) + 128, prefill, 128);
        dataPointer[y] = lastLinesUsed;

        // Get new data and count packed info

        int64_t newDataAndCount = ((int64_t)dataPointer) & 0x0000ffffffffffffL;

        newDataAndCount |= ((int64_t)linesUsed) << 48;

        // Attempt to update the data & count atomically. This command will Only
        // succeed if the data stored at dataAndCount is equal to
        // lastDataAndCount, and will return the value present just before the
        // write took place
        int64_t lastDataAndCount2 = InterlockedCompareExchangeRelease64(
            (LONG64*)&dataAndCount, newDataAndCount, lastDataAndCount);

        if (lastDataAndCount2 == lastDataAndCount) {
            success = true;
            // Queue old data to be deleted
            queueForDelete(lastDataPointer);
//			printf("Marking for delete 0x%x\n", lastDataPointer);
#ifdef LIGHT_COMPRESSION_STATS
            count = linesUsed;
#endif
        } else {
            // If we didn't succeed, queue data that we made to be deleted, and
            // try again
            queueForDelete(dataPointer);
            //			printf("Marking for delete (fail) 0x%x\n",
            //dataPointer);
        }
    } while (!success);
}

void SparseLightStorage::getPlaneIndicesAndData(unsigned char** planeIndices,
                                                unsigned char** data) {
    unsigned char* indicesAndData =
        (unsigned char*)(dataAndCount & 0x0000ffffffffffff);

    *planeIndices = indicesAndData;
    *data = indicesAndData + 128;
}

void SparseLightStorage::queueForDelete(unsigned char* data) {
    // Add this into a queue for deleting. This shouldn't be actually deleted
    // until tick has been called twice from when the data went into the queue.
    deleteQueue[deleteQueueIndex].Push(data);
}

void SparseLightStorage::tick() {
    // We have 3 queues for deleting. Always delete from the next one after
    // where we are writing to, so it should take 2 ticks before we ever delete
    // something, from when the request to delete it came in
    int freeIndex = (deleteQueueIndex + 1) % 3;

    //	printf("Free queue: %d,
    //%d\n",deleteQueue[freeIndex].GetEntryCount(),deleteQueue[freeIndex].GetAllocated());
    unsigned char* toFree = NULL;
    do {
        toFree = deleteQueue[freeIndex].Pop();
//		if( toFree ) printf("Deleting 0x%x\n", toFree);
// Determine correct means to free this data - could have been allocated either
// with XPhysicalAlloc or malloc
#ifdef _XBOX
        if ((unsigned int)toFree >= MM_PHYSICAL_4KB_BASE) {
            XPhysicalFree(toFree);
        } else
#endif
        {
            free(toFree);
        }
    } while (toFree);

    deleteQueueIndex = (deleteQueueIndex + 1) % 3;
}

// Update storage with a new values for dataAndCount, repeating as necessary if
// other simultaneous writes happen.
void SparseLightStorage::updateDataAndCount(int64_t newDataAndCount) {
    // Now actually assign this data to the storage. Just repeat until
    // successful, there isn't any useful really that we can merge the results
    // of this with any other simultaneous writes that might be happening.
    bool success = false;
    do {
        int64_t lastDataAndCount = dataAndCount;
        unsigned char* lastDataPointer =
            (unsigned char*)(lastDataAndCount & 0x0000ffffffffffff);

        // Attempt to update the data & count atomically. This command will Only
        // succeed if the data stored at dataAndCount is equal to
        // lastDataAndCount, and will return the value present just before the
        // write took place
        int64_t lastDataAndCount2 = InterlockedCompareExchangeRelease64(
            (LONG64*)&dataAndCount, newDataAndCount, lastDataAndCount);

        if (lastDataAndCount2 == lastDataAndCount) {
            success = true;
            // Queue old data to be deleted
            //			printf("Marking for delete 0x%x (full
            //replace)\n", lastDataPointer);
            queueForDelete(lastDataPointer);
        }
    } while (!success);

#ifdef LIGHT_COMPRESSION_STATS
    count = (newDataAndCount >> 48) & 0xffff;
#endif
}

// Attempt to compress the stored data. This method makes no guarantee of
// success - if it fails due to something else writing to the storage whilst
// this is running, then it won't actually do anything.
int SparseLightStorage::compress() {
    unsigned char _planeIndices[128];
    bool needsCompressed = false;

    int64_t lastDataAndCount = dataAndCount;

    unsigned char* planeIndices =
        (unsigned char*)(lastDataAndCount & 0x0000ffffffffffff);
    unsigned char* data = planeIndices + 128;

    int planesToAlloc = 0;
    for (int i = 0; i < 128; i++) {
        if (planeIndices[i] == ALL_0_INDEX) {
            _planeIndices[i] = ALL_0_INDEX;
        } else if (planeIndices[i] == ALL_15_INDEX) {
            _planeIndices[i] = ALL_15_INDEX;
        } else {
            unsigned char* pucData = &data[128 * planeIndices[i]];
            bool all0 = true;
            bool all15 = true;
            for (int j = 0; j < 128; j++)  // 16 x 16 x 4-bits
            {
                if (*pucData != 0) all0 = false;
                if (*pucData != 255) all15 = false;
                pucData++;
            }
            if (all0) {
                _planeIndices[i] = ALL_0_INDEX;
                needsCompressed = true;
            } else if (all15) {
                _planeIndices[i] = ALL_15_INDEX;
                needsCompressed = true;
            } else {
                _planeIndices[i] = planesToAlloc++;
            }
        }
    }

    if (needsCompressed) {
        unsigned char* newIndicesAndData =
            (unsigned char*)malloc(128 + 128 * planesToAlloc);
        unsigned char* pucData = newIndicesAndData + 128;
        XMemCpy(newIndicesAndData, _planeIndices, 128);

        for (int i = 0; i < 128; i++) {
            if (newIndicesAndData[i] < ALL_0_INDEX) {
                XMemCpy(pucData, &data[128 * planeIndices[i]], 128);
                pucData += 128;
            }
        }

        // Get new data and count packed info

        int64_t newDataAndCount =
            ((int64_t)newIndicesAndData) & 0x0000ffffffffffffL;

        newDataAndCount |= ((int64_t)planesToAlloc) << 48;

        // Attempt to update the data & count atomically. This command will Only
        // succeed if the data stored at dataAndCount is equal to
        // lastDataAndCount, and will return the value present just before the
        // write took place
        int64_t lastDataAndCount2 = InterlockedCompareExchangeRelease64(
            (LONG64*)&dataAndCount, newDataAndCount, lastDataAndCount);

        if (lastDataAndCount2 != lastDataAndCount) {
            // Failed to write. Don't bother trying again... being very
            // conservative here.
            //			printf("Marking for delete 0x%x (compress
            //fail)\n", newIndicesAndData);
            queueForDelete(newIndicesAndData);
        } else {
            // Success
            queueForDelete(planeIndices);
//			printf("Successfully compressed to %d planes, to delete
//0x%x\n", planesToAlloc, planeIndices);
#ifdef LIGHT_COMPRESSION_STATS
            count = planesToAlloc;
#endif
        }

        return planesToAlloc;
    } else {
        return (int)((lastDataAndCount >> 48) & 0xffff);
    }
}

bool SparseLightStorage::isCompressed() {
    int count = (dataAndCount >> 48) & 0xffff;
    return (count < 127);
}

void SparseLightStorage::write(DataOutputStream* dos) {
    int count = (dataAndCount >> 48) & 0xffff;
    dos->writeInt(count);
    unsigned char* dataPointer =
        (unsigned char*)(dataAndCount & 0x0000ffffffffffff);
    byteArray wrapper(dataPointer, count * 128 + 128);
    dos->write(wrapper);
}

void SparseLightStorage::read(DataInputStream* dis) {
    int count = dis->readInt();
    unsigned char* dataPointer = (unsigned char*)malloc(count * 128 + 128);
    byteArray wrapper(dataPointer, count * 128 + 128);
    dis->readFully(wrapper);

    int64_t newDataAndCount = ((int64_t)dataPointer) & 0x0000ffffffffffffL;

    newDataAndCount |= ((int64_t)count) << 48;

    updateDataAndCount(newDataAndCount);
}