Using TGLHudText for objects label

[LefjuCabro]

Hello,

In my scene I have spheres and for each spheres I want to display their labels near them.

TGLFlatText don't convince me because it is in 3D so I am using TGLHudText which is in 2D.

My problem is that TGLHudText don't move when I move camera. In order to fix that, in each camera moves, I destroy then create new TGLHudText. The result is good but not really optimised when I have a lot of spheres (500).

Is there any proper method to move TGLHudText when I moved the scene.

Attached, here is an example of my issue.

Thanks

Delphi Berlin Upd1 and GLScene 1.4.1.

[Jerome.D (BeanzMaster)]

hello for what you want to do you must use TGLFlatText create it as a child of your sphere and set options to twosidelighting and set depthtest to false (no z write) see GLGizmoEx units and demo TGLFlattext work well

[LefjuCabro]

Hello,

I tried your method, it works but this is not the result I want: I always want labels in front of me whatever the camera position. I don't want "mirror" labels for users.

Is there something I can do with TGLFlatText to do that ?

Regards

[Jerome.D (BeanzMaster)]

Hi can you post a sample source and some screenshots, please. I'll can get in touch when i'll have a little time.

[LefjuCabro]

Hi here is an example in "Labels.7z".

In this project, I had 2 labels (1 TGLFlatText and 1 TGLHUDText) on each spheres. I show one of these labels with the checkbox.

TGLFlatText:
OK: this item moves automatically when camera turns and when zoom in/out.
KO: mirror label according to camera position. Is there a way to have visible not mirrored TGLFlatText whatever camera position ?

TGLHudText
OK: this item moves when camera turns but I have to implement the new position on each moves.
KO: zoom in/out. TGLHudText don't "follow" the sphere

Regarding to this project, I don't know if I had better to use TGLFlatText or TGLHudText.

[Jerome.D (BeanzMaster)]

You need update HUDText's position under GLSceneViewerMouseWheel

procedure TForm1.FormMouseWheel(Sender: TObject; Shift: TShiftState;
  WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
var
 objPos, winPos : TAffineVector;
begin
    GLSceneViewer1.Camera.AdjustDistanceToTarget(Power(1.1, WheelDelta/120));
  if (not CheckBox1.Checked) then
    begin
      if Assigned(HUD_Sphere1) then
      begin
        objPos.V[0]:= GLSphere1.Position.X ;
        objPos.V[1]:= GLSphere1.Position.Y ;
        objPos.V[2]:= GLSphere1.Position.Z ;
        winPos := GLSceneViewer1.Buffer.WorldToScreen (objPos) ;

        HUD_Sphere1.Position.X:= winPos.V[0] ;
        HUD_Sphere1.Position.Y:= GLSceneViewer1.Height - Round(winPos.V[1]) ;
        HUD_Sphere1.Position.Z:= winPos.V[2] ;
      end;
      //
      if Assigned(HUD_Sphere2) then
      begin
        objPos.V[0]:= GLSphere2.Position.X ;
        objPos.V[1]:= GLSphere2.Position.Y ;
        objPos.V[2]:= GLSphere2.Position.Z ;
        winPos := GLSceneViewer1.Buffer.WorldToScreen (objPos) ;

        HUD_Sphere2.Position.X:= winPos.V[0] ;
        HUD_Sphere2.Position.Y:= GLSceneViewer1.Height - Round(winPos.V[1]) ;
        HUD_Sphere2.Position.Z:= winPos.V[2] ;
      end;
    end;
end;

[LefjuCabro]

Quite simply... Thanks

RESOLVED