You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
o3de/Code/CryEngine/RenderDll/Common/Textures/TextureArrayAlloc.h

96 lines
2.5 KiB
C++

/*
* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
* its licensors.
*
* For complete copyright and license terms please see the LICENSE at the root of this
* distribution (the "License"). All use of this software is governed by the License,
* or, if provided, by the license below or the license accompanying this file. Do not
* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*
*/
// Original file Copyright Crytek GMBH or its affiliates, used under license.
#ifndef CRYINCLUDE_CRYENGINE_RENDERDLL_COMMON_TEXTURES_TEXTUREARRAYALLOC_H
#define CRYINCLUDE_CRYENGINE_RENDERDLL_COMMON_TEXTURES_TEXTUREARRAYALLOC_H
#pragma once
template <bool LT256, bool LT65536>
struct CTextureArrayAllocHlp
{
typedef size_t T;
};
template <>
struct CTextureArrayAllocHlp<true, true>
{
typedef uint8 T;
};
template <>
struct CTextureArrayAllocHlp<false, true>
{
typedef uint16 T;
};
template <typename T, size_t Capacity>
class CTextureArrayAlloc
{
public:
typedef typename CTextureArrayAllocHlp < Capacity < 256, Capacity < 65536>::T TId;
public:
CTextureArrayAlloc()
{
for (TId i = 0; i < Capacity; ++i)
{
m_freeIDs[i] = i;
}
m_numFree = Capacity;
std::make_heap(m_freeIDs, m_freeIDs + Capacity, HeapComp());
}
T* Allocate()
{
if (m_numFree > 0)
{
TId idx = m_freeIDs[0];
std::pop_heap(m_freeIDs, m_freeIDs + m_numFree, HeapComp());
--m_numFree;
return &m_arr[idx];
}
return NULL;
}
void Release(T* p)
{
TId idx = static_cast<TId>(std::distance(m_arr, p));
m_freeIDs[m_numFree++] = idx;
std::push_heap(m_freeIDs, m_freeIDs + m_numFree, HeapComp());
}
T* GetArray() { return m_arr; }
const T* GetArray() const { return m_arr; }
T* GetPtrFromIdx(TId idx) { return &m_arr[idx]; }
TId GetIdxFromPtr(T* p) { return static_cast<TId>(p - &m_arr[0]); }
TId GetNumLive() const { return Capacity - m_numFree; }
TId GetNumFree() const { return m_numFree; }
private:
struct HeapComp
{
bool operator () (TId a, TId b) const
{
return b < a;
}
};
private:
T m_arr[Capacity];
TId m_freeIDs[Capacity];
TId m_numFree;
};
#endif // CRYINCLUDE_CRYENGINE_RENDERDLL_COMMON_TEXTURES_TEXTUREARRAYALLOC_H