Plot 3D surfaces

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Drawing2D;

namespace Plot3D
{
    public partial class Plot3DMainForm : Form
    {
        Surface3DRenderer sr;
        
        public Plot3DMainForm()
        {
            InitializeComponent();
            sr = new Surface3DRenderer(70, 35, 40, 0, 0, ClientRectangle.Width, ClientRectangle.Height, 0.5, 0, 0);
            sr.ColorSchema = new ColorSchema(tbHue.Value);
            sr.SetFunction("sin(x1)*cos(x2)/(sqrt(sqrt(x1*x1+x2*x2))+1)*10");
            Form1_Resize(null, null);
            ResizeRedraw = true;
            DoubleBuffered = true;
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            e.Graphics.Clear(BackColor);
            sr.RenderSurface(e.Graphics);
        }

        private void Form1_Resize(object sender, EventArgs e)
        {
            sr.ReCalculateTransformationsCoeficients(70, 35, 40, 0, 0, ClientRectangle.Width, ClientRectangle.Height, 0.5, 0, 0);
        }

        private void tbHue_Scroll(object sender, EventArgs e)
        {
            sr.ColorSchema = new ColorSchema(tbHue.Value);
            Invalidate();
        }
    }
}