unit uvkuInstance;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils,
  Vulkan;

type
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  TvkuPhysicalDeviceArr = array of VkPhysicalDevice;
  TvkuInstance = class(TObject)
  private
    fHandle:            VkInstance;
    fAllocCallbacks:    PVkAllocationCallbacks;
    fPhysicalDevices:   TvkuPhysicalDeviceArr;
    fInstanceCommands:  TVkInstanceCommands;

    procedure UpdatePhysicalDevices;
  protected
    procedure CreateHandle(const aCreateInfo: PVkInstanceCreateInfo; const aAllocCallbacks: PVkAllocationCallbacks);
    {%H-}constructor Create;
  public
    property Handle:                                VkInstance            read fHandle;
    property InstanceCommands:                      TVkInstanceCommands   read fInstanceCommands;

    function GetPhysicalDevices: TvkuPhysicalDeviceArr;

    constructor Create(
      const aCreateInfo: TVkInstanceCreateInfo);

    constructor Create(
      const aCreateInfo: TVkInstanceCreateInfo;
      const aAllocCallbacks: TVkAllocationCallbacks);

    destructor Destroy; override;
  end;

implementation

uses
  uvkuUtils;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//TvkuInstance///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
procedure TvkuInstance.UpdatePhysicalDevices;
var
  c: VkUint32;
  err: TVkResult;
begin
  if (Length(fPhysicalDevices) > 0) then
    exit;

  err := InstanceCommands.vkEnumeratePhysicalDevices(fHandle, @c, nil);
  if (err < VK_SUCCESS) then
    raise TvkuErrorException.Create('unable to get physical device number', err);
  SetLength(fPhysicalDevices, c);

  err := InstanceCommands.vkEnumeratePhysicalDevices(fHandle, @c, @fPhysicalDevices[0]);
  if (err < VK_SUCCESS) then
    raise TvkuErrorException.Create('unable to get physical devices', err);
end;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
procedure TvkuInstance.CreateHandle(const aCreateInfo: PVkInstanceCreateInfo; const aAllocCallbacks: PVkAllocationCallbacks);
var e: TVkResult;
begin
  if Assigned(aAllocCallbacks) then begin
    new(fAllocCallbacks);
    fAllocCallbacks^ := aAllocCallbacks^;
  end;
  e := vkCreateInstance(aCreateInfo, fAllocCallbacks, @fHandle);
  if (e < VK_SUCCESS) then
    raise TvkuErrorException.Create('unable to create vulkan instance', e);
  fInstanceCommands := LoadInstanceCommands(fHandle);
  if not Assigned(InstanceCommands) then
    raise TvkuException.Create('unable to load instance commands');
end;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
constructor TvkuInstance.Create;
begin
  inherited Create;
  fHandle         := nil;
  fAllocCallbacks := nil;
end;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
function TvkuInstance.GetPhysicalDevices: TvkuPhysicalDeviceArr;
begin
  UpdatePhysicalDevices;
  result := fPhysicalDevices;
end;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
constructor TvkuInstance.Create(const aCreateInfo: TVkInstanceCreateInfo);
begin
  Create;
  CreateHandle(@aCreateInfo, nil);
end;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
constructor TvkuInstance.Create(const aCreateInfo: TVkInstanceCreateInfo; const aAllocCallbacks: TVkAllocationCallbacks);
begin
  Create;
  CreateHandle(@aCreateInfo, @aAllocCallbacks);
end;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
destructor TvkuInstance.Destroy;
begin
  if (fHandle <> VK_INVALID_HANDLE) then begin
    InstanceCommands.vkDestroyInstance(fHandle, fAllocCallbacks);
    fHandle := VK_INVALID_HANDLE;
  end;
  if Assigned(fAllocCallbacks) then begin
    Dispose(fAllocCallbacks);
    fAllocCallbacks := nil;
  end;
  FreeAndNil(fInstanceCommands);
  inherited Destroy;
end;

end.