TBGL- multiple displays

[ReneMiner]

More than one TBGL-display quite easy to achieve - but needs UI-Canvas.

Example shows how two different "scenes" can be displayed in two different canvas-controls at same time.
Not using scene/entity-system here but is doable rendering different scenes to different output also.
Even works in seperate dialogs.
If displaying same scene from different points of view then camera-entity has to be placed according to the current view.

Uses "UI", "TBGL"

' -- ID numbers of controls
Begin ControlID
  %lCanvas1
  %lCanvas2
   
  %bClose 
  
  %myTimer 
End ControlID

Begin Const
  %MAIN_WIDTH   = 640
  %MAIN_HEIGHT  = 480

  %timeOut      = 20   ' -- Determines graphics refresh rate in milliseconds
End Const

Function TBMain()

  Local hDlg As DWord

  Dialog New Pixels, 0, "Dialog with TBGL",-1,-1, %MAIN_WIDTH, %MAIN_HEIGHT, _
                                     %WS_POPUP Or %WS_VISIBLE Or _
                                     %WS_CLIPCHILDREN Or %WS_CAPTION Or _
                                     %WS_SYSMENU Or %WS_MINIMIZEBOX Or %WS_MAXIMIZEBOX, 0 To hDlg
    
    ' -- Place controls: 
    Control Add Label, hDlg, %lCanvas1, "", 5, 5, %MAIN_WIDTH/2-10, %MAIN_HEIGHT-40
      Control Set Color hDlg, %lCanvas1, %BLACK, %BLACK
   
    Control Add Label, hDlg, %lCanvas2, "", %Main_Width/2+5, 5, %MAIN_WIDTH/2-10, %MAIN_HEIGHT-40
      Control Set Color hDlg, %lCanvas2, %BLACK, %BLACK
   
    Control Add Button, hDlg, %bClose, "Close", 5, %MAIN_HEIGHT-30, %MAIN_WIDTH - 10, 25
   
    Dialog Show Modal hDlg, Call dlgCallback
    
End Function   
 
CallBack Function dlgCallback()
  Static hCtrl As DWord
  
  Select Case CBMSG
    
    Case %WM_INITDIALOG
      ' just init timer
      Dialog Set Timer CBHNDL, %myTimer, %timeOut, %NULL
  
    Case %WM_TIMER
      Control Handle CBHNDL, %lCanvas1 To hCtrl
      RenderMyImage(hCtrl, %lCanvas1)

      Control Handle CBHNDL, %lCanvas2 To hCtrl
      RenderMyImage(hCtrl, %lCanvas2)

    Case %WM_CLOSE 
      Control Handle CBHNDL, %lCanvas1 To hCtrl
       If TBGL_CanvasBound(hCtrl) Then TBGL_ReleaseCanvas(hCtrl)      
      Control Handle CBHNDL, %lCanvas2 To hCtrl
       If TBGL_CanvasBound(hCtrl) Then TBGL_ReleaseCanvas(hCtrl)      
   
      Dialog Kill Timer CBHNDL, %myTimer
      
    Case %WM_COMMAND
      Select Case CBCTL
        
        Case %bClose
          If CBCTLMSG = %BN_CLICKED Then Dialog End CBHNDL
        
      End Select
      
  End Select
End Function


Sub RenderMyImage( ByVal hCtrl As DWord, ByVal ID_Canvas As Long )


  TBGL_BindCanvas(hCtrl)     ' no need to update canvas-proprtions...
      
  If TBGL_CanvasBound(hCtrl) Then
    
    TBGL_UseLighting(%TRUE)
    TBGL_UseLightSource(%GL_LIGHT0, %TRUE)
    TBGL_SetLightParameter(%GL_LIGHT0, %TBGL_LIGHT_POSITION, 15, 10, 15, 1)

 
    TBGL_ClearFrame
      TBGL_Camera(5, 5, 5, 0, 0, 0)  
      
      If ID_Canvas = %lCanvas1 Then
       ' show "scene 1"
        TBGL_Box(1, 1, 1)
      Else
      ' show "scene 2"
        TBGL_Sphere(1)
      EndIf      
    
    TBGL_DrawFrame
    
  EndIf  
End Sub

Edit: limitation removed