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procedure TForm1.FormCreate(Sender: TObject);
begin
  DC:= GetDC(Handle);
  if not InitOpenGL then Application.Terminate;
  RC:= CreateRenderingContext( DC,
                               [opDoubleBuffered],
                               32,
                               24,
                               0,0,0,
                               0);
  ActivateRenderingContext(DC, RC);
end;					

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unit ogl;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, dglOpenGL, ExtCtrls;

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormResize(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure IdleHandler(Sender: TObject; var Done: Boolean);
  private
    { Private-Deklarationen }
       StartTime, TimeCount, FrameCount  : Cardinal; //FrameCounter
    Frames, DrawTime                  : Cardinal; // Timebased Movement
    procedure SetupGL;
    procedure Render;
    procedure ErrorHandler;
  public
    { Public-Deklarationen }
    DC                                : HDC;  //Handle auf Zeichenfläche
    RC                                : HGLRC;//Rendering Context
  end;

var
  Form1: TForm1;
  h_DC: hDC;
  hRC: HGLRC;
  CX, CY, CZ, Radius: TGLFloat;
  const NearClipping = 1;
        FarClipping  = 1000;
implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  DC:= GetDC(Handle);
  if not InitOpenGL then Application.Terminate;
  RC:= CreateRenderingContext( DC,
                               [opDoubleBuffered],
                               32,
                               24,
                               0,0,0,
                               0);
  ActivateRenderingContext(DC, RC);
  SetupGl;
  Application.OnIdle := IdleHandler;
  Form1.Caption := InttoStr(Frames) + ' FPS';
end;

procedure TForm1.SetupGL;
begin
  glClearColor(0, 0, 0, 1); //Hintergrundfarbe
  glEnable(GL_DEPTH_TEST);          //Tiefentest aktivieren
  glEnable(GL_CULL_FACE);           //Backface Culling aktivieren
end;

procedure TForm1.FormResize(Sender: TObject);
var tmpBool : Boolean;
begin
  glViewport(0, 0, ClientWidth, ClientHeight);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity;
  gluPerspective(45.0, ClientWidth/ClientHeight, NearClipping, FarClipping);

  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity;
  IdleHandler(Sender, tmpBool);
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  DeactivateRenderingContext;
  DestroyRenderingContext(RC);
  ReleaseDC(Handle, DC);
end;

procedure TForm1.Render;
begin
  glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT);

  glMatrixMode(GL_PROJECTION);
  glLoadIdentity;
  gluPerspective(45.0, ClientWidth/ClientHeight, NearClipping, FarClipping);

  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  glTranslatef(0, 0, -2);

  glPushMatrix();
   glBegin(GL_Quads);
     glTexCoord2f(0,1); glVertex3f(-0.5,-0.5,0);
     glTexCoord2f(1,1); glVertex3f(0.5,-0.5,0);
     glTexCoord2f(1,0); glVertex3f(0.5,0.5,0);
     glTexCoord2f(0,0); glVertex3f(-0.5,0.5,0);
   glEnd;
  glPopMatrix();
  
  SwapBuffers(DC);
end;
procedure TForm1.Timer1Timer(Sender: TObject);
begin
   inc(FrameCount);
   Render;
   If FrameCount = 20 then
      begin
           ErrorHandler;
           FrameCount := 0;
      end;
end;

procedure TForm1.IdleHandler(Sender: TObject; var Done: Boolean);
begin
  StartTime:= GetTickCount;
  Render;
  DrawTime:= GetTickCount - StartTime;
  Inc(TimeCount, DrawTime);
  Inc(FrameCount);

  if TimeCount >= 1000 then begin
    Frames:= FrameCount;
    TimeCount:= TimeCount - 1000;
    FrameCount:= 0;
    Form1.Caption := InttoStr(Frames) + 'FPS';
    ErrorHandler;
  end;
  Done:= false;
end;

procedure TForm1.ErrorHandler;
begin
  Form1.Caption := gluErrorString(glGetError);
end;

end.