Files
ougge/src/Game/GameObjectPool.cpp

131 lines
3.4 KiB
C++

#include "GameObjectPool.hpp"
#include <bit>
#include <cstring>
namespace ougge::game {
GameObjectPool::GameObjectPool(u32 size)
{
useful_assert(size % 64 == 0, "size of GameObjectPool must be a multiple of 64");
this->size = size;
first_unused_index = 0;
buffer = new GameObject[size];
used_indices = new u64[size/64];
// std::memset(buffer, 0, size*sizeof(GameObject));
std::memset(used_indices, 0, size/8);
}
GameObjectPool::~GameObjectPool()
{
delete[] buffer;
delete[] used_indices;
}
bool GameObjectPool::isIndexUsed(u32 index)
{
return ( used_indices[index/64] & (u64(1)<<(index%64)) ) != 0;
}
u32 GameObjectPool::getNearestUnusedIndex(u32 startIndex)
{
if(startIndex >= size)
return -1;
if(!isIndexUsed(startIndex))
return startIndex;
u32 i = startIndex/64;
// mark previous bits as used
u64 u = used_indices[i] | ( (u64(1)<<startIndex%64) -1 );
while(u == u64(-1)){
i++;
if(i == size/64)
return -1;
u = used_indices[i];
}
u32 bitpos = std::countr_one(u);
if(bitpos == 64)
return -1;
u32 index = i*64 + bitpos;
return index;
}
u32 GameObjectPool::getNearestUsedIndex(u32 startIndex)
{
if(startIndex >= size)
return -1;
if(isIndexUsed(startIndex))
return startIndex;
u32 i = startIndex/64;
// mark previous bits as unused
u64 u = used_indices[i] & !( (u64(1)<<startIndex%64) -1 );
while(u == 0){
i++;
if(i == size/64)
return -1;
u = used_indices[i];
}
u32 bitpos = std::countr_zero(u);
if(bitpos == 64)
return -1;
u32 index = i*64 + bitpos;
return index;
}
GameObject& GameObjectPool::get(u32 index)
{
if(index >= size)
throw UsefulException(ougge_format("index %i is out of size %i", index, size));
if(!isIndexUsed(index))
throw UsefulException(ougge_format("there is no object at index %i", index));
return buffer[index];
}
std::pair<u32, GameObject&> GameObjectPool::emplace(GameObject&& new_obj)
{
u32 i = first_unused_index;
if(i == u32(-1))
throw UsefulException("can't put new GameObject to GameObjectPool because it's full");
buffer[i] = std::move(new_obj);
GameObject& r = buffer[i];
used_indices[i/64] |= u64(1)<<(i%64); // mark index bit as used
first_unused_index = getNearestUnusedIndex(i+1);
return std::pair<u32, GameObject&>(i, r);
}
void GameObjectPool::erase(u32 index)
{
if(index >= size)
throw UsefulException(ougge_format("index %i is out of size %i", index, size));
if(!isIndexUsed(index))
throw UsefulException(ougge_format("there is no object at index %i", index));
buffer[index] = GameObject();
used_indices[index/64] &= ~(u64(1)<<(index%64)); // mark index bit as unused
if(index < first_unused_index)
first_unused_index = index;
}
GameObjectPool::iterator::iterator(GameObjectPool* pool, u32 index)
: pool(pool), index(index)
{
}
std::pair<u32, GameObject&> GameObjectPool::iterator::operator*()
{
if(index >= pool->size)
throw UsefulException("can't get value of end() iterator");
GameObject& r = pool->buffer[index];
return std::pair<u32, GameObject&>(index, r);
}
GameObjectPool::iterator& GameObjectPool::iterator::operator++()
{
index = pool->getNearestUsedIndex(index+1);
return *this;
}
}