Offscreen rendering

[jmtrivial]

Dear Developers, Maintainers and Community,

I'm looking for a way to do offscreen rendering of a 3D scene using GLScene within Delphi.

If I understand correctly, I should:

• create a TGLScene
• create a Camera and add it as a child of TGLScene
• create an objet (such as TGLMesh) and add it as a child of the scene
• create a TGLMemoryViewer, set its width and height
• tune a bit the parameters of its Buffer
• adjust camera's position and orientation
• finally do a rendering and save it as a TImage

Unfortunally, I get an exception when I run the rendering.

  // create the scene
    scene := TGLScene.Create(nil);

    // create a camera
    camera := TGLCamera.Create(scene);
    scene.Objects.AddChild(camera);

    // get my build my mesh
    mesh := [...]
    // add the mesh to the scene
    scene.Objects.AddChild(mesh);

    // create the viewer
    memViewer := TGLMemoryViewer.Create(nil);
    memViewer.Width := 512;
    memViewer.Height := 512;

    // set viewers's camera
    memViewer.Camera := camera;

    // adjust the buffer
    memViewer.Buffer.BackgroundAlpha := 0;
    memViewer.Buffer.BackgroundColor := clBlack;
    memViewer.Buffer.Lighting := False;
    memViewer.Buffer.AntiAliasing := aaNone;
    memViewer.Buffer.ShadeModel := smFlat;
    memViewer.Buffer.ColorDepth := cd24bits;
    memViewer.Buffer.ContextOptions := [roDestinationAlpha];


    // adjust the properties of the camera
    camera.FocalLength := 1.0;
    camera.CameraStyle := csOrthogonal;
    camera.Position.X := 0;
    camera.Position.Y := 0;
    camera.Position.Z := -1;
    camera.Direction.X := 0;
    camera.Direction.Y := 0;
    camera.Direction.Z := 1;

    // create the image to be filled
    Result := TBitmap.Create;
    Result.PixelFormat := pf24bit;
    Result.Width := largeur;
    Result.Height := hauteur;
      
    // render the 3D scene 
    memViewer.Render(); // <- here is the exception
    

Did I miss something obvious?

[jmtrivial]

adding uses GLS.WindowsContext fixes this issue.