#include "Globals.h"
#include "RegionCache.h"
#include <QMutexLocker>
#include <QThreadPool>
#include "ChunkSource.h"
#include "RegionLoader.h"
#include "Region.h"
RegionCache::RegionCache(QObject * parent) :
super(parent)
{
m_Cache.setMaxCost(1024 * 1024 * 1024); // 1 GiB of memory for the cache
}
RegionPtr RegionCache::fetch(int a_RegionX, int a_RegionZ)
{
// Retrieve from the cache:
quint32 hash = getRegionHash(a_RegionX, a_RegionZ);
RegionPtr * res;
{
QMutexLocker lock(&m_Mtx);
res = m_Cache[hash];
// If succesful and region loaded, return the retrieved value:
if ((res != nullptr) && (*res)->isValid())
{
return *res;
}
}
// If the region is in cache but not valid, it means it has been already queued for rendering, do nothing now:
if (res != nullptr)
{
return RegionPtr(nullptr);
}
// There's no such item in the cache, create it now:
try
{
res = new RegionPtr(new Region);
}
catch (const std::bad_alloc &)
{
/* Allocation failed (32-bit process hit the 2 GiB barrier?)
This may happen even with the cache set to 1 GiB, because it contains shared ptrs and so they may be
held by another place in the code even when they are removed from cache.
*/
return RegionPtr(nullptr);
}
if (res == nullptr)
{
return RegionPtr(nullptr);
}
{
QMutexLocker lock(&m_Mtx);
m_Cache.insert(hash, res, sizeof(Region));
}
// Queue the region for rendering:
queueRegionRender(a_RegionX, a_RegionZ, *res);
// Return failure, the region is not yet rendered:
return RegionPtr(nullptr);
}
void RegionCache::setChunkSource(std::shared_ptr<ChunkSource> a_ChunkSource)
{
// Replace the chunk source:
m_ChunkSource = a_ChunkSource;
// Clear the cache:
QMutexLocker lock(&m_Mtx);
m_Cache.clear();
}
void RegionCache::reload()
{
assert(m_ChunkSource.get() != nullptr);
// Reload the chunk source:
m_ChunkSource->reload();
// Clear the cache:
QMutexLocker lock(&m_Mtx);
m_Cache.clear();
}
void RegionCache::gotRegion(int a_RegionX, int a_RegionZ)
{
emit regionAvailable(a_RegionX, a_RegionZ);
}
quint32 RegionCache::getRegionHash(int a_RegionX, int a_RegionZ)
{
// Simply join the two coords into a single int
// The coords will never be larger than 16-bits, so we can do this safely
return (((static_cast<quint32>(a_RegionX) & 0xffff) << 16) | (static_cast<quint32>(a_RegionZ) & 0xffff));
}
void RegionCache::queueRegionRender(int a_RegionX, int a_RegionZ, RegionPtr & a_Region)
{
// Create a new loader task:
RegionLoader * loader = new RegionLoader(a_RegionX, a_RegionZ, a_Region, m_ChunkSource);
connect(loader, SIGNAL(loaded(int, int)), this, SLOT(gotRegion(int, int)));
QThreadPool::globalInstance()->start(loader);
}
