unit Vulkan;

{$IFDEF FPC}
  {$MODE Delphi}
  {$IFNDEF WINDOWS}
    {$LINKLIB c}
  {$ENDIF}
  {$MINENUMSIZE 4}
{$ENDIF}

{$IFDEF Win32}
  {$DEFINE VK_WIN}
{$ENDIF}

{$IFDEF Win64}
  {$DEFINE VK_WIN}
{$ENDIF}

{$IFDEF linux}
  {$DEFINE VK_LINUX}
  {$DEFINE VK_CDECL}
{$ENDIF}

{$IFDEF DARWIN}
  {$DEFINE VK_MAC}
  {$DEFINE VK_CDECL}
{$ENDIF}

interface

{%INTERFACE%}

const
    VULKAN_LIBNAME = 'vulkan-1.dll';

type
  VkVersion = VkInt32;

function vkMakeVersion(const aMajor, aMinor, aPatch: Integer): VkVersion;
function vkGetVersionMajor(const aVersion: VkVersion): Integer;
function vkGetVersionMinor(const aVersion: VkVersion): Integer;
function vkgetVersionPatch(const aVersion: VkVersion): Integer;

function  InitializeVulkan(const aLibName: String = VULKAN_LIBNAME): Boolean;
procedure FinalizeVulkan;

implementation

type
{$IF DEFINED(VK_WIN)}
  TvkLibHandle = TLibHandle;
{$ELSE}
  TvkLibHandle = Pointer;
{$ENDIF}

const
{$IF DEFINED(VK_WIN)}
  InvalidLibHandle = 0;
{$ELSE}
  InvalidLibHandle = nil;
{$ENDIF}

var
  vkLibHandle: TvkLibHandle = InvalidLibHandle;

function vkLoadLibrary(const aLibName: String): TvkLibHandle;
begin
  {$IF DEFINED(VK_WIN)}
  result := LoadLibrary(aLibName);
  {$ELSE}
  result := InvalidLibHandle;
  {$ENDIF}
end;

function vkGetProcAddress(const aProcName: String; aLibHandle: TvkLibHandle = InvalidLibHandle): Pointer;
begin
  if (aLibHandle = InvalidLibHandle) then
    aLibHandle := vkLibHandle;
  {$IF DEFINED(VK_WIN)}
  result := GetProcAddress(aLibHandle, AnsiString(aProcName));
  {$ELSE}
  result := nil;
  {$ENDIF}
end;

procedure vkFreeLibrary(var aLibHandle: TvkLibHandle);
begin
  if (aLibHandle <> InvalidLibHandle) then begin
    {$IF DEFINED(VK_WIN)}
    FreeLibrary(aLibHandle);
    {$ENDIF}
    aLibHandle := InvalidLibHandle;
  end;
end;

function vkMakeVersion(const aMajor, aMinor, aPatch: Integer): VkVersion;
begin
  result := (aMajor shl 22) or (aMinor shl 12) or aPatch;
end;

function vkGetVersionMajor(const aVersion: VkVersion): Integer;
begin
  result := (aVersion shr 22);
end;

function vkGetVersionMinor(const aVersion: VkVersion): Integer;
begin
  result := (aVersion shr 12) and $3FF;
end;

function vkGetVersionPatch(const aVersion: VkVersion): Integer;
begin
  result := (aVersion and $FFF);
end;

function InitializeVulkan(const aLibName: String = VULKAN_LIBNAME): Boolean;
begin
  FinalizeVulkan;
  vkLibHandle := vkLoadLibrary(aLibName);
  result := (vkLibHandle <> InvalidLibHandle);
  if not result then
    exit;

  {%IMPLEMENTATION%}
end;

procedure FinalizeVulkan;
begin
  vkFreeLibrary(vkLibHandle);
end;

initialization

finalization
  FinalizeVulkan;

end.