How can I process the .obj File I read? #1703

BaranKanatcomtr · 2024-03-02T10:57:37Z

BaranKanatcomtr
Mar 2, 2024

Sorry for my bad English, English is not my native language.

Hello My Friends,

I am developing a windows form application with C#. I want to show an .obj file that I downloaded from the internet from the application in 3D. I managed to read the OBJ file successfully.

.obj function I read

static private List<Vector3> vertices = new List<Vector3>();
static private List<Vector3> normals = new List<Vector3>();
static private List<Vector2> texCoords = new List<Vector2>();
static private List<int[]> faces = new List<int[]>();

static public void ParseFile(string filePath)
{
    using (StreamReader reader = new StreamReader(filePath))
    {
        string line;
        
        while ((line = reader.ReadLine()) != null)
        {
            string[] tokens = line.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);

            if (tokens.Length == 0)
                continue;

            CultureInfo culture = CultureInfo.InvariantCulture;

            switch (tokens[0])
            {

                case "v":
                    float x = float.Parse(tokens[1], CultureInfo.InvariantCulture.NumberFormat);
                    float y = float.Parse(tokens[2], CultureInfo.InvariantCulture.NumberFormat);
                    float z = float.Parse(tokens[3], CultureInfo.InvariantCulture.NumberFormat);
                    vertices.Add(new Vector3(x, y, z));
                    break;

                case "vn":
                    float nx = float.Parse(tokens[1], CultureInfo.InvariantCulture.NumberFormat);
                    float ny = float.Parse(tokens[2], CultureInfo.InvariantCulture.NumberFormat);
                    float nz = float.Parse(tokens[3], CultureInfo.InvariantCulture.NumberFormat);
                    normals.Add(new Vector3(nx, ny, nz));
                    break;

                case "vt":
                    float u = float.Parse(tokens[1], CultureInfo.InvariantCulture.NumberFormat);
                    float v = float.Parse(tokens[2], CultureInfo.InvariantCulture.NumberFormat);
                    texCoords.Add(new Vector2(u, v));
                    break;

                case "f":
                    int[] face = new int[9];
                    for (int i = 0; i < 3; i++)
                    {
                        string[] vertexTokens = tokens[i + 1].Split(new char[] { '/' }, StringSplitOptions.None);
                        face[i * 3] = int.Parse(vertexTokens[0]) - 1; // vertex index
                        face[i * 3 + 1] = int.Parse(vertexTokens[1]) - 1; // texture coordinate index
                        face[i * 3 + 2] = int.Parse(vertexTokens[2]) - 1; // normal index
                    }
                    faces.Add(face);
                    break;
            }
        }


    }
}

But after this I don't know how to render this .obj file I read. I am sharing my entire code with you below. Can you help with this?

using System.Globalization;
using System.Windows.Forms;
using OpenTK;
using OpenTK.Graphics.OpenGL;

namespace _3dmodel_6_obj_render
{

    public partial class Form1 : Form
    {

        /* 3D Models */
        GLControl glControl1;
        /* 3D Models */

        
        static private List<Vector3> vertices = new List<Vector3>();
        static private List<Vector3> normals = new List<Vector3>();
        static private List<Vector2> texCoords = new List<Vector2>();
        static private List<int[]> faces = new List<int[]>();

        static public void ParseFile(string filePath)
        {
          //I shared this funciton above.
        }

        public Form1()
        {
            InitializeComponent();

            glControl1 = new GLControl();
            this.Controls.Add(glControl1);
            glControl1.Dock = DockStyle.Fill;

            // glControl'ü panelin tamamına yay
            panel1.Controls.Add(glControl1);
            ParseFile("D:\\obj\\Plane.obj");
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            /* 3D Model */
            
            glControl1.MakeCurrent();

            GL.ClearColor(Color.AntiqueWhite);
            GL.Enable(EnableCap.DepthTest);

            glControl1.Paint += GlControl1_Paint;
            Application.Idle += Application_Idle;
            /* 3D Model */
  
        }

        private void Application_Idle(object sender, EventArgs e)
        {
            glControl1.Invalidate();
        }

        private void glControl1_Load(object sender, EventArgs e)
        {
            GL.ClearColor(Color.Pink); 
            GL.Enable(EnableCap.DepthTest);
        }

        private void GlControl1_Paint(object sender, PaintEventArgs e)
        {
            GL.Clear(ClearBufferMask.ColorBufferBit);
            GL.Clear(ClearBufferMask.DepthBufferBit);

            Matrix4 perspective = Matrix4.CreatePerspectiveFieldOfView(1.04f, 4 / 3, 1, 10000);
            Matrix4 lookat = Matrix4.LookAt(25, 0, 0, 0, 0, 0, 0, 1, 0);
            GL.MatrixMode(MatrixMode.Projection);
            GL.LoadIdentity();
            GL.LoadMatrix(ref perspective);
            GL.MatrixMode(MatrixMode.Modelview);
            GL.LoadIdentity();
            GL.LoadMatrix(ref lookat);
            GL.Viewport(0, 0, glControl1.Width, glControl1.Height);
            GL.Enable(EnableCap.DepthTest);
            GL.DepthFunc(DepthFunction.Less);


            
            GL.End();
            glControl1.SwapBuffers();
        }
    }
}