unit uvkuDescriptorPool;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils,
  Vulkan, uvkuBase, uvkuTypes;

type
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  TvkuDescriptorPool = class(TvkuAllocHandle)
  private
    fHandle: VkDescriptorPool;
    fDeviceCommands: TVkDeviceCommands;

    procedure CreateHandle(const aCreateInfo: TVkDescriptorPoolCreateInfo);
  public
    property Handle:          VkDescriptorPool      read fHandle;
    property DeviceCommands:  TVkDeviceCommands read fDeviceCommands;

    function AllocateDescriptorSet(
      const aDescriptorSetLayout: VkDescriptorSetLayout): VkDescriptorSet;
    function AllocateDescriptorSets(
      const aDescriptorSetLayouts: array of VkDescriptorSetLayout): TVkDescriptorSetArr;
    procedure FreeDescriptorSet(
      const aDescriptorSet: VkDescriptorSet);
    procedure FreeDescriptorSets(
      const aDescriptorSets: TVkDescriptorSetArr);

    constructor Create(
      const aCreateInfo: TVkDescriptorPoolCreateInfo;
      const aDeviceCommands: TVkDeviceCommands;
      const aAllocCallbacks: PVkAllocationCallbacks = nil);
    constructor Create(
      const aHandle: VkDescriptorPool;
      const aOwnsHandle: Boolean;
      const aDeviceCommands: TVkDeviceCommands;
      const aAllocCallbacks: PVkAllocationCallbacks = nil);
    destructor Destroy; override;
  end;

implementation

uses
  uvkuUtils;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//TvkuDescriptorPool/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
procedure TvkuDescriptorPool.CreateHandle(const aCreateInfo: TVkDescriptorPoolCreateInfo);
var err: TVkResult;
begin
  if not Assigned(fDeviceCommands.vkCreateDescriptorPool) then
    raise TvkuInvalidFuncPtrException.Create('vkCreateDescriptorPool');
  err := fDeviceCommands.vkCreateDescriptorPool(fDeviceCommands.Device, @aCreateInfo, AllocCallbacks, @fHandle);
  if (err <> VK_SUCCESS) then
    raise TvkuErrorException.Create('unable to create descriptor pool', err);
end;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
function TvkuDescriptorPool.AllocateDescriptorSet(const aDescriptorSetLayout: VkDescriptorSetLayout): VkDescriptorSet;
begin
  result := AllocateDescriptorSets([ aDescriptorSetLayout ])[0];
end;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
function TvkuDescriptorPool.AllocateDescriptorSets(const aDescriptorSetLayouts: array of VkDescriptorSetLayout): TVkDescriptorSetArr;
var
  AllocInfo: TVkDescriptorSetAllocateInfo;
  err: TVkResult;
begin
  if not Assigned(fDeviceCommands.vkAllocateDescriptorSets) then
    raise TvkuInvalidFuncPtrException.Create('vkAllocateDescriptorSets');
  FillByte(AllocInfo, SizeOf(AllocInfo), 0);
  AllocInfo.sType               := VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
  AllocInfo.pNext               := nil;
  AllocInfo.descriptorPool      := fHandle;
  AllocInfo.descriptorSetCount  := Length(aDescriptorSetLayouts);
  AllocInfo.pSetLayouts         := @aDescriptorSetLayouts[0];
  SetLength(result, AllocInfo.descriptorSetCount);
  err := fDeviceCommands.vkAllocateDescriptorSets(fDeviceCommands.Device, @AllocInfo, @result[0]);
  if (err <> VK_SUCCESS) then
    raise TvkuErrorException.Create('unable to allocate descriptor sets', err);
end;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
procedure TvkuDescriptorPool.FreeDescriptorSet(const aDescriptorSet: VkDescriptorSet);
begin
  FreeDescriptorSets(TVkDescriptorSetArr.Create(aDescriptorSet));
end;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
procedure TvkuDescriptorPool.FreeDescriptorSets(const aDescriptorSets: TVkDescriptorSetArr);
var err: TVkResult;
begin
  if not Assigned(fDeviceCommands.vkFreeDescriptorSets) then
    raise TvkuInvalidFuncPtrException.Create('vkFreeDescriptorSets');
  err := fDeviceCommands.vkFreeDescriptorSets(fDeviceCommands.Device, fHandle, Length(aDescriptorSets), @aDescriptorSets[0]);
  if (err <> VK_SUCCESS) then
    raise TvkuErrorException.Create('unable to free descriptor sets', err);
end;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
constructor TvkuDescriptorPool.Create(const aCreateInfo: TVkDescriptorPoolCreateInfo;
  const aDeviceCommands: TVkDeviceCommands; const aAllocCallbacks: PVkAllocationCallbacks);
begin
  inherited Create;
  fDeviceCommands := aDeviceCommands;
  SetAllocCallbacks(aAllocCallbacks);
  CreateHandle(aCreateInfo);
end;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
constructor TvkuDescriptorPool.Create(const aHandle: VkDescriptorPool; const aOwnsHandle: Boolean;
  const aDeviceCommands: TVkDeviceCommands; const aAllocCallbacks: PVkAllocationCallbacks);
begin
  inherited Create;
  fHandle         := aHandle;
  fDeviceCommands := aDeviceCommands;
  OwnsHandle      := aOwnsHandle;
  SetAllocCallbacks(aAllocCallbacks);
end;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
destructor TvkuDescriptorPool.Destroy;
begin
  if OwnsHandle and (fHandle <> VK_INVALID_NDP_HANDLE) then
    fDeviceCommands.vkDestroyDescriptorPool(fDeviceCommands.Device, fHandle, AllocCallbacks);
  fHandle := VK_INVALID_NDP_HANDLE;
  inherited Destroy;
end;

end.