/// <summary>
/// refreshes the back ground for <see cref="ForeGroundDraw"/>.
/// </summary>
public void RefreshBackGround()
{
Texture Savet = texture;
GLShader S = Shader;
BackBuffer.BackGround = BackColor;
if (BackBuffer.FboHandle <= 0)
{
BackBuffer.Init((int)ViewPort.Width, (int)ViewPort.Height);
}
RenderKind K = RenderKind;
RenderKind = RenderKind.Render;
Matrix P = ProjectionMatrix;
ProjectionMatrix = Matrix.scale(new xyz(1, -1, 1)) * P;
//--------- Draw scene to Backbuffer
BackBuffer.EnableWriting();
OnPaint();
BackBuffer.DisableWriting();
texture = Savet;
ProjectionMatrix = P;
RenderKind = K;
Shader = S;
}