DrawBackground Method (Viewport)

Visual Basic
C#

'Declaration
 
Protected Friend Overridable Sub DrawBackground( _
   ByVal context As RenderContextBase, _
   ByVal reflection As Boolean, _
   ByVal reflectionIntensity As Single, _
   ByVal parentColor As Color, _
   ByVal pickMatrix As Transformation _
)

protected internal virtual void DrawBackground( 
   RenderContextBase context,
   bool reflection,
   float reflectionIntensity,
   Color parentColor,
   Transformation pickMatrix
)

Parameters

context: The render context
reflection: If true, it's drawing the planar reflections (when there are no shaders)
reflectionIntensity: THe intensity of the planar reflections
parentColor: The color of the parent
pickMatrix: The matrix to restrict the rendering to the given rectangle (important for ViewportLayout.RenderToBitmap).

The following code fragment demonstrates how to override the DrawBackground() method to draw a custom background.

C#

class MyViewport : Viewport
{
      protected override void DrawBackground()
      {
          // Draws standard background
          base.DrawBackground();
 
          // Draws a white rectangle with a margin of 50 pixel from the viewport's border
          gl.Begin(gl.QUADS);
 
          gl.Color3ub(255, 255, 255);
          gl.Vertex2i(50, 50);
          gl.Vertex2i(Width - 50, 50);
          gl.Vertex2i(Width-50, Height -50);
          gl.Vertex2i(50, Height - 50);
          
          gl.End();         
      }
}

VB.NET

Class MyViewport
    Inherits Viewport
    Protected Overrides Sub DrawBackground()
        ' Draws standard background
        MyBase.DrawBackground()
 
        ' Draws a white rectangle with a margin of 50 pixel from the viewport's border
        gl.Begin(gl.QUADS)
 
        gl.Color3ub(255, 255, 255)
        gl.Vertex2i(50, 50)
        gl.Vertex2i(Width - 50, 50)
        gl.Vertex2i(Width - 50, Height - 50)
        gl.Vertex2i(50, Height - 50)
 
        gl.[End]()
    End Sub
End Class

Reference

Viewport Class
Viewport Members