Delphi OpenGL and CrossPlatform Lazarus (Multilang)
lazarus / 70-OpenGL

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TheProgrammer · 2011-09-04 07:18

Code: [Select]unit foforras;

{$IFDEF FPC}
  {$MODE Delphi}
{$ENDIF}

interface

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

type
  Tfoablak = class(TForm)
    timer: TTimer;
    procedure Create(Sender: TObject);
    procedure Destory(Sender: TObject);
    procedure gltimer(Sender: TObject);
    procedure SetupGL;
    procedure Render;
  private
  { Private }
  public
  { Public }
  end;

var
  foablak : Tfoablak;
  DC : HDC;
  RC : HGLRC;
  NearClipping : integer;
  FarClipping  : integer;
  StartTime, TimeCount, FrameCount : Cardinal;
  Frames, DrawTime : Cardinal;

implementation

{$IFNDEF FPC}
  {$R *.dfm}
{$ELSE}
  {$R *.lfm}
{$ENDIF}

procedure Tfoablak.Create(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;
  InitOpenGL;
end;


procedure Tfoablak.SetupGL;
begin
  glClearColor(0, 0, 0, 0); //hattér színe: RGBx, X = ?
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_CULL_FACE);
end;


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


procedure Tfoablak.Render;
begin
  NearClipping := 1;
  FarClipping  := 1000;

  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, -500); //+-415x +-210y a max -500nál, eddig
látható

  SwapBuffers(DC);
end;


procedure Tfoablak.gltimer(Sender: TObject);
begin

   inc(FrameCount);
   Render;
   If FrameCount = 20 then
      begin
           FrameCount := 0;
      end;
end;

end.
How can i create crossplatform OpenGL Appliction in Lazarus?
I must use Windows Library because i use HDC and HGLRC.
I would like to use dglOpenGL library because this is newer version.
(OpenGL Shading Language 4.20)

Hogyan tudok platformfüggetlen alkalmazást csinálni?
Muszáj használnom a Windows könyvtárat a HDC és HGLRC miatt.
Szeretném a dpgOpenGL könyvtárat használni mert ez újabb. (OpenGL
Shading Language 4.20)

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BigChimp · 2011-09-04 08:06

I know nothing about OpenGL, but have you checked the wiki:
http://wiki.lazarus.freepascal.org/OpenGL
There's also an OpenGL tutorial linked to there...

Hope this helps,
BigChimp

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User137 · 2011-09-04 11:25

If you want you could look for hints from my game engine nxPascal:
http://www.pascalgamedevelopment.com/showthread.php?8785-nxPascal

It compiles with Lazarus and Delphi, and because it does not include
Windows in uses-list anywhere it should be crossplatform. There are
code differences between Lazarus and Delphi which can be solved with
compiler directives {$IFDEF ...} I have included samples for 2
different methods of window creation. Mainly with Lazarus you want to
use lazOpenGLContext package.
I also use latest dglOpenGL header.

There is also many more graphics libs on pascalgamedevelopment.

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TheProgrammer · 2011-09-04 11:52

Thanks!
Kössz!

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avra · 2011-09-05 08:06

If I remember well, OpenGL sample in Lazarus CT edition were
multiplatform.

http://www.pilotlogic.com/codetyphon/help/opengl_samples.htm
http://www.pilotlogic.com/codetyphon/help/index.html?glscene_samples.h
tm

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TheProgrammer · 2011-09-05 15:47

Thanks!
Kössz!