unit uglcContextGtk2GLX;

{ Package:      OpenGLCore
  Prefix:       glc - OpenGL Core
  Beschreibung: diese Unit enthält eine Klassen-Kapselung für OpenGL Kontexte für Linux
  Hint:         diese Unit sollte niemals direkt genutzt werden (siehe uglcContext) }

interface

uses
  SysUtils, Controls, uglcContext, LCLType, XUtil, XLib, gdk2x, gtk2, gdk2, dglOpenGL,
  LMessages, uglcContextGtkCustomVisual;

type
  EGLXError = class(EGLError);

  TRenderControl = class(TCustomVisualControl)
  private
    fTarget: TWinControl;
  protected
    procedure WndProc(var Message: TLMessage); override;
  public
    property Target: TWinControl read fTarget write fTarget;
  end;

  { TglcContextGtk2GLX }

  TglcContextGtk2GLX = class(TglcContext)
  private
    FVisual: PXVisualInfo;
    FDisplay: PDisplay;
    FWidget: PGtkWidget;
    FContext: GLXContext;
    FRenderControl: TRenderControl;
    procedure UpdateVisual(const aControl: TWinControl);
  protected
    procedure OpenContext; override;
  public
    constructor Create(const aControl: TWinControl; const aPixelFormatSettings: TglcContextPixelFormatSettings); override; overload;
    constructor Create(const aControl: TWinControl; const aPixelFormatSettings: TglcContextPixelFormatSettings; const aVersionSettings: TglcContextVersionSettings); override; overload;
    destructor Destroy; override;

    procedure CloseContext; override;
    procedure Activate; override;
    procedure Deactivate; override;
    function IsActive: boolean; override;
    procedure SwapBuffers; override;
    procedure SetSwapInterval(const aInterval: GLint); override;
    procedure Share(const aContext: TglcContext); override;

    class function ChangeDisplaySettings(const aWidth, aHeight,
      aBitPerPixel, aFreq: Integer; const aFlags: TglcDisplayFlags): Boolean; override;
    class function IsAnyContextActive: boolean; override;
  end;

implementation

type
  TGLIntArray = packed array of GLInt;

{$region messages -fold}
procedure TRenderControl.WndProc(var Message: TLMessage);
begin
  case Message.msg of
    //LM_ACTIVATEITEM,
    //LM_CHANGED,
    //LM_FOCUS,
    LM_CLICKED,
    //LM_RELEASED,
    LM_ENTER,
    LM_LEAVE,
    //LM_CHECKRESIZE,
    //LM_SETEDITABLE,
    //LM_MOVEWORD,
    //LM_MOVEPAGE,
    //LM_MOVETOROW,
    //LM_MOVETOCOLUMN,
    //LM_KILLCHAR,
    //LM_KILLWORD,
    //LM_KILLLINE,
    //LM_CLOSEQUERY,
    //LM_DRAGSTART,
    //LM_MONTHCHANGED,
    //LM_YEARCHANGED,
    //LM_DAYCHANGED,
    LM_LBUTTONTRIPLECLK,
    LM_LBUTTONQUADCLK,
    LM_MBUTTONTRIPLECLK,
    LM_MBUTTONQUADCLK,
    LM_RBUTTONTRIPLECLK,
    LM_RBUTTONQUADCLK,
    LM_MOUSEENTER,
    LM_MOUSELEAVE,
    LM_XBUTTONTRIPLECLK,
    LM_XBUTTONQUADCLK,

    //SC_SIZE,
    //SC_MOVE,
    //SC_MINIMIZE,
    //SC_MAXIMIZE,
    //SC_NEXTWINDOW,
    //SC_PREVWINDOW,
    //SC_CLOSE,
    SC_VSCROLL,
    SC_HSCROLL,
    SC_MOUSEMENU,
    SC_KEYMENU,
    //SC_ARRANGE,
    //SC_RESTORE,
    //SC_TASKLIST,
    //SC_SCREENSAVE,
    //SC_HOTKEY,
    //SC_DEFAULT,
    //SC_MONITORPOWER,
    //SC_CONTEXTHELP,
    //SC_SEPARATOR,

    //LM_MOVE,
    //LM_SIZE,
    LM_ACTIVATE,
    LM_SETFOCUS,
    LM_KILLFOCUS,
    //LM_ENABLE,
    //LM_GETTEXTLENGTH,
    //LM_SHOWWINDOW,
    //LM_CANCELMODE,
    //LM_DRAWITEM,
    //LM_MEASUREITEM,
    //LM_DELETEITEM,
    //LM_VKEYTOITEM,
    //LM_CHARTOITEM,
    //LM_COMPAREITEM,
    //LM_WINDOWPOSCHANGING,
    //LM_WINDOWPOSCHANGED,
    //LM_NOTIFY,
    //LM_HELP,
    //LM_NOTIFYFORMAT,
    //LM_CONTEXTMENU,
    //LM_NCCALCSIZE,
    //LM_NCHITTEST,
    //LM_NCPAINT,
    //LM_NCACTIVATE,
    //LM_GETDLGCODE,
    LM_NCMOUSEMOVE,
    LM_NCLBUTTONDOWN,
    LM_NCLBUTTONUP,
    LM_NCLBUTTONDBLCLK,
    LM_KEYDOWN,
    LM_KEYUP,
    LM_CHAR,
    LM_SYSKEYDOWN,
    LM_SYSKEYUP,
    LM_SYSCHAR,
    LM_COMMAND,
    LM_SYSCOMMAND,
    LM_TIMER,
    LM_HSCROLL,
    LM_VSCROLL,
    //LM_CTLCOLORMSGBOX,
    //LM_CTLCOLOREDIT,
    //LM_CTLCOLORLISTBOX,
    //LM_CTLCOLORBTN,
    //LM_CTLCOLORDLG,
    //LM_CTLCOLORSCROLLBAR,
    //LM_CTLCOLORSTATIC,
    LM_MOUSEMOVE,
    LM_LBUTTONDOWN,
    LM_LBUTTONUP,
    LM_LBUTTONDBLCLK,
    LM_RBUTTONDOWN,
    LM_RBUTTONUP,
    LM_RBUTTONDBLCLK,
    LM_MBUTTONDOWN,
    LM_MBUTTONUP,
    LM_MBUTTONDBLCLK,
    LM_MOUSEWHEEL,
    LM_XBUTTONDOWN,
    LM_XBUTTONUP,
    LM_XBUTTONDBLCLK,
    //LM_PARENTNOTIFY,
    //LM_CAPTURECHANGED,
    //LM_DROPFILES,
    //LM_SELCHANGE,
    LM_CUT,
    LM_COPY,
    LM_PASTE,
    //LM_CLEAR,
    //LM_CONFIGUREEVENT,
    //LM_EXIT,
    //LM_QUIT,
    //LM_NULL,
    //LM_PAINT,
    //LM_ERASEBKGND,
    //LM_SETCURSOR,
    //LM_SETFONT:

    //CM_ACTIVATE,
    //CM_DEACTIVATE,
    //CM_FOCUSCHANGED,
    //CM_PARENTFONTCHANGED,
    //CM_PARENTCOLORCHANGED,
    //CM_HITTEST,
    //CM_VISIBLECHANGED,
    //CM_ENABLEDCHANGED,
    //CM_COLORCHANGED,
    //CM_FONTCHANGED,
    //CM_CURSORCHANGED,
    //CM_TEXTCHANGED,
    CM_MOUSEENTER,
    CM_MOUSELEAVE,
    //CM_MENUCHANGED,
    //CM_APPSYSCOMMAND,
    //CM_BUTTONPRESSED,
    //CM_SHOWINGCHANGED,
    //CM_ENTER,
    //CM_EXIT,
    //CM_DESIGNHITTEST,
    //CM_ICONCHANGED,
    //CM_WANTSPECIALKEY,
    //CM_RELEASE,
    //CM_FONTCHANGE,
    //CM_TABSTOPCHANGED,
    //CM_UIACTIVATE,
    //CM_CONTROLLISTCHANGE,
    //CM_GETDATALINK,
    //CM_CHILDKEY,
    //CM_HINTSHOW,
    //CM_SYSFONTCHANGED,
    //CM_CONTROLCHANGE,
    //CM_CHANGED,
    //CM_BORDERCHANGED,
    //CM_BIDIMODECHANGED,
    //CM_PARENTBIDIMODECHANGED,
    //CM_ALLCHILDRENFLIPPED,
    //CM_ACTIONUPDATE,
    //CM_ACTIONEXECUTE,
    //CM_HINTSHOWPAUSE,
    //CM_DOCKNOTIFICATION,
    CM_MOUSEWHEEL,
    //CM_APPSHOWBTNGLYPHCHANGED,
    //CM_APPSHOWMENUGLYPHCHANGED,

    //CN_BASE,
    //CN_CHARTOITEM,
    //CN_COMMAND,
    //CN_COMPAREITEM,
    //CN_CTLCOLORBTN,
    //CN_CTLCOLORDLG,
    //CN_CTLCOLOREDIT,
    //CN_CTLCOLORLISTBOX,
    //CN_CTLCOLORMSGBOX,
    //CN_CTLCOLORSCROLLBAR,
    //CN_CTLCOLORSTATIC,
    //CN_DELETEITEM,
    //CN_DRAWITEM,
    CN_HSCROLL,
    //CN_MEASUREITEM,
    //CN_PARENTNOTIFY,
    //CN_VKEYTOITEM,
    CN_VSCROLL,
    CN_KEYDOWN,
    CN_KEYUP,
    CN_CHAR,
    CN_SYSKEYUP,
    CN_SYSKEYDOWN,
    CN_SYSCHAR,
    CN_NOTIFY:
    begin
      if Assigned(fTarget) then
        Message.Result := fTarget.Perform(Message.msg, Message.wParam, Message.lParam);
    end;
  end;
  inherited WndProc(Message);
end;

{$endregion}

function CreateOpenGLContextAttrList(UseFB: boolean; pf: TglcContextPixelFormatSettings): TGLIntArray;
var
  p: integer;

  procedure Add(i: integer);
  begin
    SetLength(Result, p+1);
    Result[p]:=i;
    inc(p);
  end;

  procedure CreateList;
  begin
    if UseFB then begin Add(GLX_X_RENDERABLE); Add(1); end;
    if pf.DoubleBuffered then begin
      if UseFB then begin
        Add(GLX_DOUBLEBUFFER); Add(1);
      end else
        Add(GLX_DOUBLEBUFFER);
    end;
    if not UseFB and (pf.ColorBits>24) then Add(GLX_RGBA);
    if UseFB then begin
      Add(GLX_DRAWABLE_TYPE);
      Add(GLX_WINDOW_BIT);
    end;
    Add(GLX_RED_SIZE);  Add(8);
    Add(GLX_GREEN_SIZE);  Add(8);
    Add(GLX_BLUE_SIZE);  Add(8);
    if pf.ColorBits>24 then
      Add(GLX_ALPHA_SIZE);  Add(8);
    Add(GLX_DEPTH_SIZE);  Add(pf.DepthBits);
    Add(GLX_STENCIL_SIZE);  Add(pf.StencilBits);
    Add(GLX_AUX_BUFFERS);  Add(pf.AUXBuffers);

    if pf.MultiSampling > 1 then begin
      Add(GLX_SAMPLE_BUFFERS_ARB); Add(1);
      Add(GLX_SAMPLES_ARB); Add(pf.MultiSampling);
    end;

    Add(0); { 0 = X.None (be careful: GLX_NONE is something different) }
  end;

begin
  SetLength(Result, 0);
  p:=0;
  CreateList;
end;

function FBglXChooseVisual(dpy:PDisplay; screen:longint; attrib_list:Plongint):PXVisualInfo;
type
  PGLXFBConfig = ^GLXFBConfig;
var
  FBConfigsCount: integer;
  FBConfigs: PGLXFBConfig;
  FBConfig: GLXFBConfig;
begin
  Result:= nil;
  FBConfigsCount:=0;
  FBConfigs:= glXChooseFBConfig(dpy, screen, attrib_list, @FBConfigsCount);
  if FBConfigsCount = 0 then
    exit;

  { just choose the first FB config from the FBConfigs list.
    More involved selection possible. }
  FBConfig := FBConfigs^;
  Result:=glXGetVisualFromFBConfig(dpy, FBConfig);
end;


{ TglcContextGtk2GLX }

procedure TglcContextGtk2GLX.UpdateVisual(const aControl: TWinControl);
var
  attrList: TGLIntArray;
  drawable: PGdkDrawable;
begin
  if not Assigned(aControl) then
    raise EArgumentException.Create('aControl is not assigned');

  {
    Temporary (realized) widget to get to display
  }
  FWidget:= {%H-}PGtkWidget(PtrUInt(aControl.Handle));
  gtk_widget_realize(FWidget);
  drawable:= GTK_WIDGET(FWidget)^.window;

  FDisplay:= GDK_WINDOW_XDISPLAY(drawable);

  {
    Find a suitable visual from PixelFormat using GLX 1.3 FBConfigs or
    old-style Visuals
  }
  if Assigned(glXChooseFBConfig) then begin
    attrList := CreateOpenGLContextAttrList(true, fPixelFormatSettings);
    FVisual  := FBglXChooseVisual(FDisplay, DefaultScreen(FDisplay), @attrList[0]);
    if not Assigned(FVisual) and (fPixelFormatSettings.MultiSampling > 1) then begin
      fPixelFormatSettings.MultiSampling := 1;
      attrList := CreateOpenGLContextAttrList(true, fPixelFormatSettings);
      FVisual  := FBglXChooseVisual(FDisplay, DefaultScreen(FDisplay), @attrList[0]);
    end;
  end;
  if not Assigned(FVisual) then begin
    attrList := CreateOpenGLContextAttrList(false, fPixelFormatSettings);
    FVisual  := glXChooseVisual(FDisplay, DefaultScreen(FDisplay), @attrList[0]);
    if not Assigned(FVisual) and (fPixelFormatSettings.MultiSampling > 1) then begin
      fPixelFormatSettings.MultiSampling := 1;
      attrList := CreateOpenGLContextAttrList(false, fPixelFormatSettings);
      FVisual  := glXChooseVisual(FDisplay, DefaultScreen(FDisplay), @attrList[0]);
    end;
  end;
  if not Assigned(FVisual) then
    raise EGLXError.Create('choose visual failed');

  {
    Most widgets inherit the drawable of their parent. In contrast to Windows, descending from
    TWinControl does not mean it's actually always a window of its own.
    Famous example: TPanel is just a frame painted on a canvas.
    Also, the LCL does somethin weird to colormaps in window creation, so we have
    to use a custom widget here to have full control about visual selection.
  }
  FRenderControl:= TRenderControl.Create(aControl, FVisual^.visual^.visualid);
  try
    FRenderControl.Parent := aControl;
    FRenderControl.HandleNeeded;
    FRenderControl.Target := aControl;
  except
    FreeAndNil(FRenderControl);
    raise;
  end;

  {
    Real Widget handle, unrealized!!!
  }
  FWidget:= FRenderControl.Widget;
  gtk_widget_realize(FWidget);
  drawable:= GTK_WIDGET(FWidget)^.window;
  FDisplay:= GDK_WINDOW_XDISPLAY(drawable);

  // FRenderControl.Align:= alClient breaks the context or something
  FRenderControl.BoundsRect := aControl.ClientRect;
  FRenderControl.Anchors    := [akLeft, akTop, akRight, akBottom];
end;

procedure TglcContextGtk2GLX.OpenContext;
var
  Attribs: array of GLint;
  tmpContext: GLXContext;
  glxID: GLXDrawable;
begin
  inherited OpenContext;

  if not Assigned(FVisual) then
    raise EGLXError.Create('Failed to find Visual');

  tmpContext := glXCreateContext(FDisplay, FVisual, nil, true);
  if fUseVersion and
     (fVersionSettings.Major <> GLC_CONTEXT_VERSION_UNKNOWN) and
     (fVersionSettings.Minor <> GLC_CONTEXT_VERSION_UNKNOWN) then
  begin
    // Set attributes to describe our requested context
    SetLength(Attribs, 5);
    Attribs[0] := WGL_CONTEXT_MAJOR_VERSION_ARB;
    Attribs[1] := fVersionSettings.Major;
    Attribs[2] := WGL_CONTEXT_MINOR_VERSION_ARB;
    Attribs[3] := fVersionSettings.Minor;

    // Add context flag for forward compatible context
    // Forward compatible means no more support for legacy functions like
    // immediate mode (glvertex, glrotate, gltranslate, etc.)
    if fVersionSettings.ForwardCompatible then begin
      SetLength(Attribs, Length(Attribs)+2);
      Attribs[4] := WGL_CONTEXT_FLAGS_ARB;
      Attribs[5] := WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB;
    end;

    // Attribute flags must be finalized with a zero
    SetLength(Attribs, 1);
    Attribs[High(Attribs)] := 0;

    glxID := GDK_DRAWABLE_XID(GTK_WIDGET(FWidget)^.window);
    glXMakeCurrent(FDisplay, glxID, tmpContext);
    ReadImplementationProperties;
    if not Assigned(glXCreateContextAttribsARB) or not GLX_ARB_create_context then begin
      glXDestroyContext(FDisplay, tmpContext);
      raise Exception.Create('GLX_ARB_create_context not supported');
    end;
    FContext := glXCreateContextAttribsARB(FDisplay, FVisual, nil, true, @Attribs[0]);

    glXDestroyContext(FDisplay, tmpContext);
  end else
    FContext := tmpContext;

  if (FContext = nil) then
    raise EGLXError.Create('Failed to create Context');
end;

constructor TglcContextGtk2GLX.Create(const aControl: TWinControl;
  const aPixelFormatSettings: TglcContextPixelFormatSettings);
begin
  inherited Create(aControl, aPixelFormatSettings);
  UpdateVisual(aControl);
end;

constructor TglcContextGtk2GLX.Create(const aControl: TWinControl;
  const aPixelFormatSettings: TglcContextPixelFormatSettings;
  const aVersionSettings: TglcContextVersionSettings);
begin
  inherited Create(aControl, aPixelFormatSettings, aVersionSettings);
  UpdateVisual(aControl);
end;

destructor TglcContextGtk2GLX.Destroy;
begin
  FreeAndNil(FRenderControl);
  XFree(FVisual);
  inherited Destroy;
end;

procedure TglcContextGtk2GLX.CloseContext;
begin
  if not Assigned(FWidget) then exit;
  if Assigned(FContext) then
    glXDestroyContext(FDisplay, FContext);
  FreeAndNil(FRenderControl);
end;

procedure TglcContextGtk2GLX.Activate;
var
   glxID: GLXDrawable;
begin
  if not Assigned(FWidget) then exit;
  // make sure the widget is realized
  gtk_widget_realize(FWidget);
  if not GTK_WIDGET_REALIZED(FWidget) then exit;

  // make current
  glxID := GDK_DRAWABLE_XID(GTK_WIDGET(FWidget)^.window);
  glXMakeCurrent(FDisplay, glxID, FContext);
end;

procedure TglcContextGtk2GLX.Deactivate;
var
   glxID: GLXDrawable;
begin
  if not Assigned(FWidget) then exit;
  glxID := GDK_DRAWABLE_XID(GTK_WIDGET(FWidget)^.window);
  glXMakeCurrent(FDisplay, glxID, nil);
end;

function TglcContextGtk2GLX.IsActive: boolean;
var
  glxID: GLXDrawable;
begin
  glxID := GDK_DRAWABLE_XID(GTK_WIDGET(FWidget)^.window);
  Result:= (FContext = glXGetCurrentContext()) and
           Assigned(FWidget) and
           (glxID = glXGetCurrentDrawable());
end;

procedure TglcContextGtk2GLX.SwapBuffers;
var
  glxID: GLXDrawable;
begin
  if not Assigned(FWidget) then exit;
  glxID := GDK_DRAWABLE_XID(GTK_WIDGET(FWidget)^.window);
  glXSwapBuffers(FDisplay, glxID);
end;

procedure TglcContextGtk2GLX.SetSwapInterval(const aInterval: GLint);
var
  drawable: PGdkDrawable;
begin
  drawable:= GTK_WIDGET(FWidget)^.window;
  if GLX_EXT_swap_control then
    glXSwapIntervalEXT(FDisplay, GDK_WINDOW_XWINDOW(drawable), aInterval);
end;

procedure TglcContextGtk2GLX.Share(const aContext: TglcContext);
begin
  raise Exception.Create('not yet implemented');
end;

class function TglcContextGtk2GLX.{%H-}ChangeDisplaySettings(const aWidth, aHeight,
  aBitPerPixel, aFreq: Integer; const aFlags: TglcDisplayFlags): Boolean;
begin
  raise Exception.Create('not yet implemented');
end;

class function TglcContextGtk2GLX.IsAnyContextActive: boolean;
begin
  Result:= (glXGetCurrentContext()<>nil) and (glXGetCurrentDrawable()<>0);
end;

end.