How to replace glut32.dll library with freeglut.dll in Delphi XE easily (program stops suddenly)-CodePudding

I have the following issue. I'm using Glut openGL for drawing certain elements in my application written in Delphi. The library file I'm using is called glut32.dll (placed where the EXE file is standing) Now I decided to compile my app in 64-bit as other libraries it is using are going to be updated only for 64-bit. All fine, but the one thing that stops me is the glut32.dll (it is 32-bit). As the Glut project is not supported for many years already I found the freeglut alternative which claim to be replacement for the original Glut: https://freeglut.sourceforge.net/, and downloaded the freeglut.dll from here: www.transmissionzero.co.uk/software/freeglut-devel/ for MSVC.

As I looked at the .h header files it seems more or less the same as my code translation is in the *.pas files. So I tried to just load the freeglut.dll instead of glut32.dll (dll is set to the correct dll name in the function below)

    procedure LoadGlut(const dll: String);
    begin
    
      FreeGlut;
    
      hDLL := LoadLibrary(PChar(dll));
      if hDLL = 0 then raise Exception.Create('Could not load Glut from '   dll);
    
      @glutInit := GetProcAddress(hDLL, 'glutInit');
      @glutInitDisplayMode := GetProcAddress(hDLL, 'glutInitDisplayMode');
      @glutCreateWindow := GetProcAddress(hDLL, 'glutCreateWindow');
      @glutCreateSubWindow := GetProcAddress(hDLL, 'glutCreateSubWindow');
      @glutDestroyWindow := GetProcAddress(hDLL, 'glutDestroyWindow');
      @glutPostRedisplay := GetProcAddress(hDLL, 'glutPostRedisplay');
      ...

It is loading with no errors and so on, also the procedures in it, but when the application start and reach a point to use one of these functions it just stop the debugger with no error message (like pressing Ctrl F2).

    procedure DrawArrow(P1, P2: TRPoint; Color: TRGBAColor);
    var
      R : Real;
    begin
      DrawLine(P1, P2, Color);
      glColor4fv(@Color[0]);
      glPushMatrix;
        SetZAxis(P2, P1);
        R := VectorModulus(VectorDifference(P1,P2));
        glTranslated(0, 0, R);
        SetSymbolScale;
          glTranslated(0, 0, -ARROW_L);
          glutSolidCone(ARROW_W/2, ARROW_L, SOLID_SLICES, SOLID_STACKS);
        glPopMatrix;
      glPopMatrix;
    end;

The debugger shut itself at glutSolidCone(ARROW_W/2, ARROW_L, SOLID_SLICES, SOLID_STACKS); This function is defined in freeglut as well.

EDIT: If I call other simple function like glutInitDisplayMode it doesn't stop, so it seems that the library is correctly loaded. But it still keeps shutting down at glutSolidCone or other drawing functions.

I don't have much experience of using these header files and dll that comes with it, but my Delphi code should be a good translation in this case? Or not? I don't know how to debug this. What is the way to adapt my code in order to fit freeglut in it. It should be something small I think as most of the things should be the same.

Thank you for the help

CodePudding user response：

It seems that just replacing glut32.dll with freeglut.dll won't do the job properly as I guess functions inside differs a bit (or simply renaming freeglut.dll --> glut32.dll also fails). However I found a workaround published by NVIDIA: NVIDIA Cg Toolkit

It is not supported since 2013, but when installed it brings the dll version of glut32 both for 32-bit and 64-bit development. Quickly try it and it seems to work and cover what I have as definition in Glut.pas.

So if you need 64-bit version and replacement of glut32.dll it can be downloaded from there.

Meanwhile if somebody convert the freeglut headers (.h) to Delphi code it would be great as at the end the Freeglut projecy is still maintained, up-to-date and add some more useful functions in addition to the original Glut. This conversion is still beyond my knowledge.