Hi ,

I've got trouble understanding these two lines of code:

line 33 & line 34

  'TBGL_RenderMatrix2D(0,1,800,601) 'this works better but is not logic for me
  TBGL_RenderMatrix2D(1,1,800,600) 'this don't work properly
in this little piece of code

'---Script created on 12-19-2018 17:30:47 by

uses "TBGL"
uses "console"

dim htbgl as DWord 'handler for draw window

const max_x Value = 800 'window size
const max_y value = 600

Function tbmain()

  call window_init
  call draw_loop

  TBGL_DestroyWindow

end function

function draw_box()

  TBGL_Line (1,1,1,max_y)
  TBGL_Line (1,max_y,max_x,max_y)
  TBGL_Line (max_x,max_y,max_x,1)
  TBGL_Line (max_x,1,1,1)

end Function

function window_init()

  htbgl = TBGL_CreateWindowEx ("800x600 - ESC to quit", 800,600,16,%TBGL_WS_WINDOWED + %TBGL_WS_DONTSIZE)
  tbgl_ShowWindow
  'TBGL_RenderMatrix2D(0,1,800,601) 'this works better but is not logic for me
  TBGL_RenderMatrix2D(1,1,800,600) 'this don't work properly
  TBGL_Color (255,255,255)

end Function

Function draw_loop()

' -- Main loop
  While tbgl_IsWindow(htbgl)
    If tbgl_GetWindowKeyState(htbgl, %VK_ESCAPE) Then Exit While
    tbgl_ClearFrame

    call draw_box

    tbgl_DrawFrame
    tbgl_ResetKeyState()

  Wend

end Function