magnum/src/Magnum/Vk/DescriptorPool.cpp

/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
                2020, 2021, 2022, 2023, 2024, 2025
              Vladimír Vondruš <mosra@centrum.cz>

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    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
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    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
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    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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*/

#include "DescriptorPool.h"
#include "DescriptorPoolCreateInfo.h"

#include <Corrade/Containers/ArrayView.h>
#include <Corrade/Containers/Optional.h>
#include <Corrade/Containers/Pair.h>

#include "Magnum/Vk/Assert.h"
#include "Magnum/Vk/DescriptorSet.h"
#include "Magnum/Vk/DescriptorType.h"
#include "Magnum/Vk/Device.h"
#include "Magnum/Vk/Result.h"

namespace Magnum { namespace Vk {

DescriptorPoolCreateInfo::DescriptorPoolCreateInfo(const UnsignedInt maxSets, const Containers::ArrayView<const Containers::Pair<DescriptorType, UnsignedInt>> poolSizes, const Flags flags): _info{} {
    CORRADE_ASSERT(maxSets,
        "Vk::DescriptorPoolCreateInfo: there has to be at least one set", );
    /* On certain compilers, {} (empty initializer list) gets converted to an
       arrayview that's not null, interesting. Explicitly using .empty() to
       ensure the assert gets properly fired. */
    CORRADE_ASSERT(!poolSizes.isEmpty(),
        "Vk::DescriptorPoolCreateInfo: there has to be at least one pool", );

    Containers::ArrayView<VkDescriptorPoolSize> poolSizesCopy;
    _data = Containers::ArrayTuple{
        {NoInit, poolSizes.size(), poolSizesCopy}
    };
    for(std::size_t i = 0; i != poolSizes.size(); ++i) {
        CORRADE_ASSERT(poolSizes[i].second(),
            "Vk::DescriptorPoolCreateInfo: pool" << i << "of" << poolSizes[i].first() << "has no descriptors", );
        poolSizesCopy[i].type = VkDescriptorType(poolSizes[i].first());
        poolSizesCopy[i].descriptorCount = poolSizes[i].second();
    }

    _info.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO;
    _info.flags = VkDescriptorPoolCreateFlags(flags);
    _info.maxSets = maxSets;
    _info.poolSizeCount = poolSizesCopy.size();
    _info.pPoolSizes = poolSizesCopy;
}

DescriptorPoolCreateInfo::DescriptorPoolCreateInfo(const UnsignedInt maxSets, const std::initializer_list<Containers::Pair<DescriptorType, UnsignedInt>> poolSizes, const Flags flags): DescriptorPoolCreateInfo{maxSets, Containers::arrayView(poolSizes), flags} {}

DescriptorPoolCreateInfo::DescriptorPoolCreateInfo(NoInitT) noexcept {}

DescriptorPoolCreateInfo::DescriptorPoolCreateInfo(const VkDescriptorPoolCreateInfo& info):
    /* Can't use {} with GCC 4.8 here because it tries to initialize the first
       member instead of doing a copy */
    _info(info) {}

DescriptorPoolCreateInfo::DescriptorPoolCreateInfo(DescriptorPoolCreateInfo&& other) noexcept:
    /* Can't use {} with GCC 4.8 here because it tries to initialize the first
       member instead of doing a copy */
    _info(other._info),
    _data{Utility::move(other._data)}
{
    /* Ensure the previous instance doesn't reference state that's now ours */
    /** @todo this is now more like a destructible move, do it more selectively
        and clear only what's really ours and not external? */
    other._info.pNext = nullptr;
    other._info.poolSizeCount = 0;
    other._info.pPoolSizes = nullptr;
}

DescriptorPoolCreateInfo::~DescriptorPoolCreateInfo() = default;

DescriptorPoolCreateInfo& DescriptorPoolCreateInfo::operator=(DescriptorPoolCreateInfo&& other) noexcept {
    using Utility::swap;
    swap(other._info, _info);
    swap(other._data, _data);
    return *this;
}

DescriptorPool DescriptorPool::wrap(Device& device, const VkDescriptorPool handle, const HandleFlags flags) {
    DescriptorPool out{NoCreate};
    out._device = &device;
    out._handle = handle;
    out._flags = flags;
    return out;
}

DescriptorPool::DescriptorPool(Device& device, const DescriptorPoolCreateInfo& info): _device{&device}, _flags{HandleFlag::DestroyOnDestruction}, _freeAllocatedSets{!!(info->flags & VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT)} {
    MAGNUM_VK_INTERNAL_ASSERT_SUCCESS(device->CreateDescriptorPool(device, info, nullptr, &_handle));
}

DescriptorPool::DescriptorPool(NoCreateT): _device{}, _handle{} {}

DescriptorPool::DescriptorPool(DescriptorPool&& other) noexcept: _device{other._device}, _handle{other._handle}, _flags{other._flags}, _freeAllocatedSets{other._freeAllocatedSets} {
    other._handle = {};
}

DescriptorPool::~DescriptorPool() {
    if(_handle && (_flags & HandleFlag::DestroyOnDestruction))
        (**_device).DestroyDescriptorPool(*_device, _handle, nullptr);
}

DescriptorPool& DescriptorPool::operator=(DescriptorPool&& other) noexcept {
    using Utility::swap;
    swap(other._device, _device);
    swap(other._handle, _handle);
    swap(other._flags, _flags);
    swap(other._freeAllocatedSets, _freeAllocatedSets);
    return *this;
}

Containers::Pair<Result, DescriptorSet> DescriptorPool::allocateInternal(const VkDescriptorSetLayout layout) {
    DescriptorSet set{NoCreate};
    set._device = _device;
    set._pool = _handle;
    set._flags = _freeAllocatedSets ? HandleFlag::DestroyOnDestruction : HandleFlags{};

    VkDescriptorSetAllocateInfo info{};
    info.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
    info.descriptorPool = _handle;
    info.descriptorSetCount = 1;
    info.pSetLayouts = &layout;
    /* VK_ERROR_OUT_OF_POOL_MEMORY is only available since VK_KHR_maintenance1.
       It's not really clear what was supposed to happen before that. At the
       very least, running the allocateFail() test using

        ./VkDescriptorPoolVkTest --magnum-vulkan-version 1.0 --magnum-disable-extensions VK_KHR_maintenance1 --magnum-enable-layers VK_LAYER_KHRONOS_validation

       the validation layer complains that I'm allocating from a pool that
       doesn't have enough free items, which implies it used to be a user error
       and thus the driver is free to do *anything*, including random crashes,
       as noted on https://community.khronos.org/t/descriptor-pool-able-to-allocate-even-though-pool-should-be-empty/7330/6

       From practical testing, even the oldest Vulkan driver I have (ARM Mali
       on Huawei P9, Vulkan 1.0.66) seems to return VK_ERROR_OUT_OF_POOL_MEMORY
       no matter whether the extension is enabled or not. On the other hand,
       NVidia returns VK_ERROR_OUT_OF_DEVICE_MEMORY in this case. So I'm
       testing for both. */
    const Result result = MAGNUM_VK_INTERNAL_ASSERT_SUCCESS_OR((**_device).AllocateDescriptorSets(*_device, &info, &set._handle), Result::ErrorOutOfDeviceMemory, Result::ErrorOutOfPoolMemory, Result::ErrorFragmentedPool);
    return {result, Utility::move(set)};
}

DescriptorSet DescriptorPool::allocate(const VkDescriptorSetLayout layout) {
    Containers::Pair<Result, DescriptorSet> out = allocateInternal(layout);
    CORRADE_ASSERT(out.first() == Result::Success,
        "Vk::DescriptorPool::allocate(): allocation failed with" << out.first(), Utility::move(out.second()));
    return Utility::move(out.second());
}

Containers::Optional<DescriptorSet> DescriptorPool::tryAllocate(const VkDescriptorSetLayout layout) {
    Containers::Pair<Result, DescriptorSet> out = allocateInternal(layout);
    if(out.first() != Result::Success) return {};
    return Utility::move(out.second());
}

Containers::Pair<Result, DescriptorSet> DescriptorPool::allocateInternal(const VkDescriptorSetLayout layout, const UnsignedInt variableDescriptorCount) {
    DescriptorSet set{NoCreate};
    set._device = _device;
    set._pool = _handle;
    set._flags = _freeAllocatedSets ? HandleFlag::DestroyOnDestruction : HandleFlags{};

    VkDescriptorSetVariableDescriptorCountAllocateInfo variableInfo{};
    variableInfo.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_ALLOCATE_INFO;
    variableInfo.descriptorSetCount = 1;
    variableInfo.pDescriptorCounts = &variableDescriptorCount;

    VkDescriptorSetAllocateInfo info{};
    info.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
    info.pNext = &variableInfo;
    info.descriptorPool = _handle;
    info.descriptorSetCount = 1;
    info.pSetLayouts = &layout;
    /* See the note about VK_ERROR_OUT_OF_{DEVICE,POOL}_MEMORY and
       VK_KHR_maintenance1 in the other allocateInternal() implementation
       above. */
    const Result result = MAGNUM_VK_INTERNAL_ASSERT_SUCCESS_OR((**_device).AllocateDescriptorSets(*_device, &info, &set._handle), Result::ErrorOutOfDeviceMemory, Result::ErrorOutOfPoolMemory, Result::ErrorFragmentedPool);
    return {result, Utility::move(set)};
}

DescriptorSet DescriptorPool::allocate(const VkDescriptorSetLayout layout, const UnsignedInt variableDescriptorCount) {
    Containers::Pair<Result, DescriptorSet> out = allocateInternal(layout, variableDescriptorCount);
    CORRADE_ASSERT(out.first() == Result::Success,
        "Vk::DescriptorPool::allocate(): allocation failed with" << out.first(), Utility::move(out.second()));
    return Utility::move(out.second());
}

Containers::Optional<DescriptorSet> DescriptorPool::tryAllocate(const VkDescriptorSetLayout layout, const UnsignedInt variableDescriptorCount) {
    Containers::Pair<Result, DescriptorSet> out = allocateInternal(layout, variableDescriptorCount);
    if(out.first() != Result::Success) return {};
    return Utility::move(out.second());
}

void DescriptorPool::reset() {
    MAGNUM_VK_INTERNAL_ASSERT_SUCCESS((**_device).ResetDescriptorPool(*_device, _handle, 0));
}

VkDescriptorPool DescriptorPool::release() {
    const VkDescriptorPool handle = _handle;
    _handle = {};
    return handle;
}

}}