dolfuz's picture

Why even if I change the Ortho and view port I can't see farther than a cube of 1x1x1 ?

Hello, I hope some one can help me.

I'm using VB and I have this code in different functions but essentially is all the code:

    Private Sub SetupViewport()
         Dim w As Integer = GlControl1.Width  'Getting width and height to configure the view port and ortho
         Dim h As Integer = GlControl1.Height
         GL.MatrixMode(MatrixMode.Projection)  'All the transformations will be applied to the projection
         GL.Ortho(0, 0, w, h, 1, -1)   'Configuring the ortho and view port
         GL.Viewport(0, 0, w - 10, h - 10)
         GL.MatrixMode(MatrixMode.Modelview)  'All transformation will be applied to the model
    End Sub
    Private Sub GlControl1_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles GlControl1.Paint
        If Not clsBol_load Then
        End If
        GL.Clear(ClearBufferMask.ColorBufferBit Or ClearBufferMask.DepthBufferBit) 'Clearing the visual control       
        SetupViewport() ' Initialize the ortho and view port
        GL.Begin(BeginMode.Lines) 'Staring to make the models using Lines to draw lines        
        GL.Color3(Color.Yellow)  'The line will be painted in yellow
        'The line will go from 0,0,0 to 2,2,2. Because BeginMode is lines, each two Vertex OpenTK will paint         
        GL.Vertex3(0.0F, 0.0F, 0.0F)  'Using Vertex3 to put coordenades in 3 dimentions
        GL.Vertex3(2.0F, 2.0F, 2.0F)
        GL.Color3(Color.Blue)  'Changing the nex line to blue        
        GL.Vertex3(1.0F, 1.0F, 1.0F)   'The line 2 will start from 1,1,1 and end in 2, 2, 2
        GL.Vertex3(2.0F, 2.0F, 2.0F)        
        GL.End()  'Finishing drawing for the control
        GlControl1.SwapBuffers() 'After calling swapBuffers the control will paint the lines
    End Sub

This code only displays part of the yellow line (the part from 0 to 1) :(
Even when I change all the parameters of the ortho or viewport I can't make OpenTK displays the 2nd line (the blue one) that's outside the 1X1X1 cube displayed in this code.

Can anyone please help me to know why I cant see other blue line?

Thanks so much for your help!

Inline Images
OpenTK only displays part of the yello line  :(


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dolfuz's picture

Im making some dirty tricks to view all my model.

Im using the GL.Scale function in order to see the model, but I know there most be a better way to see all the model without scaling it.
Can anyone help me?

Thanks so much!

Snorkel's picture

I think the problem is this line:
GL.Ortho(0, 0, w, h, 1, -1)

Try setting you clipping planes to other values.
eg: GL.Ortho(0, 0, w, h, 0.0f, 100.0f)

Also your clipping distances shoudn't have different signs.
When you've done this, you'll have to put your camera bit away from 0,0,0 to be able to see the object.


jrwatts's picture

You've also got your GL.Ortho parameters in the wrong order, I think (should be left, right, bottom, top, near, far; not left, bottom, right, top, near, far); in fact, I believe you should be generating an error (your left and right parameters are the same), and OpenGL is actually ignoring your GL.Ortho call.