CreateWindowEx() returining 0!

[paul_nicholls]

I forgot to add that I was getting a 1407 error from GetLastError - this meant it couldn't find the window class when I was trying to use CreateWindowEx().

Anyway, I have now gotten it working in Delphi 2010, but not Lazarus

I got it working in Delphi since inside the DLL, I WAS using the built in hinstance variable in at least one place - this didn't seem to be valid inside a DLL, hence the issue.

Now after using GetModuleHandle() as the new instance value, it works in Delphi 2010.

But it still is not working in Lazarus - still comes up with the same error

I am having trouble debugging it to find out if the GetModuleHandle() is returning a valid value in Lazarus, but I suspect this is the case...

If I compile the DLL in Delphi then it works via Lazarus and Delphi, but if I compile the DLL using Lazarus, then it fails with the 1407 error using both Delphi and Lazarus...

here is the new code:

unit xeEngine_window_win;
{$I ..\bindings\xeEngine_include.inc}

interface

type
  TOnWindowUpdate = procedure of object;

function  Window_Create(Title: PWideChar; Width,Height: Word; Fullscreen: Boolean): Boolean; cdecl;
function  Window_Update(OnWindowUpdate: TOnWindowUpdate): Boolean;                           cdecl;
function  Window_Close: Boolean;                                                             cdecl;

implementation

uses
  xeEngine_main,
  Windows,
  Messages,
{$ifdef fpc}
  gl,
  glu
{$else}
  OpenGL
{$endif}
  ;

const
  cClassName  = 'xeOpenGL';

var
  WindowInfo: record
    h_Rc         : HGLRC;
    h_Dc         : HDC;
    h_Wnd        : HWND;
    h_Instance   : hinst;
    keys         : array [0..255] of BOOL;
    Active       : bool;
    FullScreen   : bool;
    Width,Height : GLsizei;
  end;

procedure ReSizeGLScene(Width,Height: GLsizei);
begin
  if (Height=0) then Height := 1;

  WindowInfo.Width  := Width;
  WindowInfo.Height := Height;

  glViewport(0, 0, WindowInfo.Width, WindowInfo.Height);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity;
  gluPerspective(45.0,WindowInfo.Width/WindowInfo.Height,0.1,100.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity;
end;

function InitGL: bool;
begin
  glShadeModel(GL_SMOOTH);
  glClearColor(0.0, 0.0, 0.0, 0.5);
  glClearDepth(1.0);
  glEnable(GL_DEPTH_TEST);
  glDepthFunc(GL_LEQUAL);
  glHint(GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST);

  Result := True;
end;

function DrawGLScene: bool;
begin
  glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT);
  glLoadIdentity;
  glTranslatef(-1.5,0.0,-6.0);
  glBegin(GL_TRIANGLES);
    glVertex3f( 0.0, 1.0, 0.0);
    glVertex3f(-1.0,-1.0, 0.0);
    glVertex3f( 1.0,-1.0, 0.0);
  glEnd;

  glTranslatef(3,0.0,0.0);
  glBegin(GL_QUADS);
    glVertex3f(-1.0, 1.0, 0.0);
    glVertex3f( 1.0, 1.0, 0.0);
    glVertex3f( 1.0,-1.0, 0.0);
    glVertex3f(-1.0,-1.0, 0.0);
  glEnd;

  Result := True;
end;

function WndProc(hWnd   : HWND;
                 msg    : UINT;
                 wParam : WPARAM;
                 lParam : LPARAM): LRESULT; stdcall;
begin
  if msg = WM_SYSCOMMAND then
  begin
    case wParam of
      SC_SCREENSAVE,SC_MONITORPOWER:
        begin
          result := 0;
          exit;
        end;
    end;
  end;

  case msg of
    WM_ACTIVATE: begin
      if Hiword(wParam) = 0 then
        WindowInfo.Active := true
      else
        WindowInfo.Active := false;

      Result := 0;
    end;
    WM_CLOSE: Begin
      PostQuitMessage(0);
      Result := 0
    end;
    WM_KEYDOWN: begin
      WindowInfo.keys[wParam] := TRUE;
      Result := 0;
    end;
    WM_KEYUP: begin
      WindowInfo.keys[wParam] := FALSE;
      Result := 0;
    end;
    WM_SIZE: begin
      ReSizeGLScene(LOWORD(lParam),HIWORD(lParam));
      Result := 0;
    end
    else
    begin
      Result := DefWindowProc(hWnd, msg, wParam, lParam);
    end;
  end;
end;

procedure KillGLWindow;
begin
  if WindowInfo.FullScreen then
  begin
    ChangeDisplaySettings(devmode(nil^),0);
    showcursor(true);
  end;

  if WindowInfo.h_rc<> 0 then
  begin
    if (not wglMakeCurrent(WindowInfo.h_Dc,0)) then
      MessageBox(0,'Release of DC and RC failed.',' Shutdown Error',MB_OK or MB_ICONERROR);
    if (not wglDeleteContext(WindowInfo.h_Rc)) then
      begin
        MessageBox(0,'Release of Rendering Context failed.',' Shutdown Error',MB_OK or MB_ICONERROR);
        WindowInfo.h_Rc:=0;
      end;
  end;

  if (WindowInfo.h_Dc = 1) and (releaseDC(WindowInfo.h_Wnd,WindowInfo.h_Dc) <> 0) then
  begin
    MessageBox(0,'Release of Device Context failed.',' Shutdown Error',MB_OK or MB_ICONERROR);
    WindowInfo.h_Dc:=0;
  end;

  if (WindowInfo.h_Wnd <> 0) and (not destroywindow(WindowInfo.h_Wnd))then
  begin
    MessageBox(0,'Could not release hWnd.',' Shutdown Error',MB_OK or MB_ICONERROR);
    WindowInfo.h_Wnd:=0;
  end;

  if (not UnregisterClass(PChar(cClassName),WindowInfo.h_Instance)) then
  begin
    MessageBox(0,'Could Not Unregister Class.','SHUTDOWN ERROR',MB_OK or MB_ICONINFORMATION);
  end;
end;

function  GetDesktopBitsPerPixel: Integer;
var
  DesktopDC: HDC;
begin
  DesktopDC := GetDC(0);
  try
    Result := GetDeviceCaps(DesktopDC, BITSPIXEL) * GetDeviceCaps(DesktopDC, PLANES);
  finally
    ReleaseDC(0, DesktopDC);
  end;
end;

function  CreateGlWindow(title: PChar; width,height: integer; FullScreenflag: bool): boolean;
var
  Pixelformat      : GLuint;
  wc               : TWndclass;
  dwExStyle        : dword;
  dwStyle          : dword;
  pfd              : pixelformatdescriptor;
  dmScreenSettings : Devmode;
  WindowRect       : TRect;
  bits             : Integer;
  LastErrorStr     : String;
begin
  bits := GetDesktopBitsPerPixel;

  WindowInfo.Active := True;

  WindowRect.Left   := 0;
  WindowRect.Top    := 0;
  WindowRect.Right  := width;
  WindowRect.Bottom := height;

  WindowInfo.h_instance := GetModuleHandle(nil);
  WindowInfo.FullScreen := FullScreenflag;

  WindowInfo.Width    := width;
  WindowInfo.Height   := height;

  wc.style         := CS_HREDRAW or CS_VREDRAW or CS_OWNDC;
  wc.lpfnWndProc   := @WndProc;
  wc.cbClsExtra    := 0;
  wc.cbWndExtra    := 0;
  wc.hInstance     := WindowInfo.h_Instance;
  wc.hIcon         := LoadIcon(0,IDI_WINLOGO);
  wc.hCursor       := LoadCursor(0,IDC_ARROW);
  wc.hbrBackground := 0;
  wc.lpszMenuName  := nil;
  wc.lpszClassName := PChar(cClassName);

  if  RegisterClass(wc) = 0 then
  begin
    Str(WindowInfo.h_instance,LastErrorStr);

    MessageBox(0,PChar('Failed To Register The Window Class: Error '+LastErrorStr),'Error',MB_OK or MB_ICONERROR);
    Result := false;
    exit;
  end;

  if WindowInfo.FullScreen then
  begin
    ZeroMemory( @dmScreenSettings, sizeof(dmScreenSettings) );

    dmScreensettings.dmSize       := sizeof(dmScreenSettings);
    dmScreensettings.dmPelsWidth  := width;
    dmScreensettings.dmPelsHeight := height;
    dmScreensettings.dmBitsPerPel := bits;
    dmScreensettings.dmFields     := DM_PELSWIDTH or DM_PELSHEIGHT;

    if (ChangeDisplaySettings(dmScreenSettings, CDS_FULLSCREEN)) <> DISP_CHANGE_SUCCESSFUL then
    begin
      if MessageBox(0,'This FullScreen Mode Is Not Supported. Use Windowed Mode Instead?'
                    ,'xeEngine',MB_YESNO or MB_ICONEXCLAMATION) = IDYES then
            WindowInfo.FullScreen := false
      else
      begin
        MessageBox(0,'Program Will Now Close.','Error',MB_OK or MB_ICONERROR);
        Result := False;
        Exit;
      end;
    end;
  end;

  if WindowInfo.FullScreen then
  begin
    dwExStyle := WS_EX_APPWINDOW;
    dwStyle   := WS_POPUP or WS_CLIPSIBLINGS or WS_CLIPCHILDREN;

    Showcursor(False);
  end
  else
  begin
    dwExStyle := WS_EX_APPWINDOW or WS_EX_WINDOWEDGE;
    dwStyle   := WS_OVERLAPPEDWINDOW or WS_CLIPSIBLINGS or WS_CLIPCHILDREN;
  end;
  AdjustWindowRectEx(WindowRect,dwStyle,false,dwExStyle);

  WindowInfo.H_wnd := CreateWindowEx(dwExStyle,
                                     PChar(cClassName),
                                     PChar(Title),
                                     dwStyle,
                                     0,0,
                                     WindowRect.Right-WindowRect.Left,
                                     WindowRect.Bottom-WindowRect.Top,
                                     0,
                                     0,
                                     WindowInfo.h_instance,
                                     nil);

  if WindowInfo.h_Wnd = 0 then
  begin
    Str(GetLastError,LastErrorStr);

    MessageBox(0,PChar('CreateWindowEx error: '+LastErrorStr),'Error',MB_OK or MB_ICONEXCLAMATION);
    KillGlWindow;
    Result := False;
    Exit;
  end;

  pfd.nSize           :=  SizeOf( PIXELFORMATDESCRIPTOR );
  pfd.nVersion        :=  1;
  pfd.dwFlags         :=  PFD_DRAW_TO_WINDOW or PFD_SUPPORT_OPENGL or PFD_DOUBLEBUFFER;
  pfd.iPixelType      :=  PFD_TYPE_RGBA;
  pfd.cColorBits      :=  bits;
  pfd.cRedBits        :=  0;
  pfd.cRedShift       :=  0;
  pfd.cGreenBits      :=  0;
  pfd.cBlueBits       :=  0;
  pfd.cBlueShift      :=  0;
  pfd.cAlphaBits      :=  0;
  pfd.cAlphaShift     :=  0;
  pfd.cAccumBits      :=  0;
  pfd.cAccumRedBits   :=  0;
  pfd.cAccumGreenBits :=  0;
  pfd.cAccumBlueBits  :=  0;
  pfd.cAccumAlphaBits :=  0;
  pfd.cDepthBits      :=  16;
  pfd.cStencilBits    :=  0;
  pfd.cAuxBuffers     :=  0;
  pfd.iLayerType      :=  PFD_MAIN_PLANE;
  pfd.bReserved       :=  0;
  pfd.dwLayerMask     :=  0;
  pfd.dwVisibleMask   :=  0;
  pfd.dwDamageMask    :=  0;

  WindowInfo.h_Dc := GetDC(WindowInfo.h_Wnd);
  if WindowInfo.h_Dc = 0 then
  begin
    KillGLWindow;
    MessageBox(0,'Cant''t create a GL device context.','Error',MB_OK or MB_ICONEXCLAMATION);
    Result:=false;
    exit;
  end;

  PixelFormat := ChoosePixelFormat(WindowInfo.h_Dc, @pfd);
  if (PixelFormat = 0) then
  begin
    KillGLWindow;
    MessageBox(0,'Cant''t Find A Suitable PixelFormat.','Error',MB_OK or MB_ICONEXCLAMATION);
    Result:=false;
    exit;
  end;

  if (not SetPixelFormat(WindowInfo.h_Dc,PixelFormat,@pfd)) then
  begin
    KillGLWindow;
    MessageBox(0,'Cant''t set PixelFormat.','Error',MB_OK or MB_ICONEXCLAMATION);
    Result := false;
    Exit;
  end;

  WindowInfo.h_Rc := wglCreateContext(WindowInfo.h_Dc);

  if WindowInfo.h_Rc = 0 then
  begin
    KillGLWindow;
    MessageBox(0,'Cant''t create a GL rendering context.','Error',MB_OK or MB_ICONEXCLAMATION);
    Result := false;
    Exit;
  end;

  if not wglMakeCurrent(WindowInfo.h_Dc, WindowInfo.h_Rc) then
  begin
    KillGLWindow;
    MessageBox(0,'Cant''t activate the GL rendering context.','Error',MB_OK or MB_ICONEXCLAMATION);
    Result := false;
    Exit;
  end;

  ShowWindow(WindowInfo.h_Wnd,SW_SHOW);
  SetForegroundWindow(WindowInfo.h_Wnd);
  SetFocus(WindowInfo.h_Wnd);
  ReSizeGLScene(width,height);

  if not InitGL then
  begin
    KillGLWindow;
    MessageBox(0,'initialization failed.','Error',MB_OK or MB_ICONEXCLAMATION);
    Result := false;
    Exit;
  end;

  Result := true;
end;

function  Window_Create(Title: PWideChar; Width,Height: Word; Fullscreen: Boolean): Boolean;
begin
  if not CreateGLWindow(PChar(Title),Width,Height,FullScreen) then
  begin
    Result := False;
    Exit;
  end;

  Result := True;
end;

function  Window_Update(OnWindowUpdate: TOnWindowUpdate): Boolean;
var
  msg: TMsg;
begin
  Result := True;

  if PeekMessage(msg, 0, 0, 0, PM_REMOVE) then
  begin
    if msg.message = WM_QUIT then
      Result := False
    else
    begin
      TranslateMessage(msg);
      DispatchMessage(msg);
    end;
  end
  else
  begin
    if (WindowInfo.Active and not(DrawGLScene) or WindowInfo.keys[VK_ESCAPE]) then
      Result := False
    else
      SwapBuffers(WindowInfo.h_Dc);
  end;

  if not Result and Assigned(OnWindowUpdate) then OnWindowUpdate;
end;

function  Window_Close: Boolean;
begin
  Result := True;
end;

end.

cheers,
Paul