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Arcball Module in C# - Tao.OpenGL

, 11 Jan 2008 CPOL
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Arcball module using Tao.OpenGL in C#.

Introduction

This article is the continuation on my Arcball module for C#. Previously, I had posted a code using CsGL. In this version, I have utilized the Tao.OpenGL wrapper and I have added Rotation/Zoom/Pan functions. I have also made use of Display Lists to speed up plot rendering. The Arcball module written here is general and not limited to OpenGL, and can be used in GDI+ and DirectX as well. Please note that my main focus in this tutorial is on the Arcball module, not on OpenGL application.

Background

Arcball (also know as RollerBall) is probably the most intuitive method to view three dimensional objects. The principle of the Arcball is based on creating a sphere around the object and letting users to click a point on the sphere and drag it to a different location. There is a bit of math involved and you can Google for it. Here are few good links to educate yourself:

The code here is a C# source code implementing an Arcball in OpenGL (Tap.OpenGL).

Screenshot - pic1.png

Here is the same object but zoomed using the mouse middle button:

Screenshot - pic2.png

And, here is when it is panned to the left using the mouse right button:

Screenshot - pic3.png

Using the code

In this version, I am using Display List, Lighting, and Blending functions. I am not going to go into the details of OpenGL programming for the sake of brevity. Create a new form, create an instance of the Arcball class, and make if fill the form rectangle. All plots should go in the public function PlotGL in Form1.cs. I am plotting a torus and a backward torus in this example.

public void PlotGL()
{
    try

    {
        lock (matrixLock)
        {
            ThisTransformation.get_Renamed(matrix);
        }

        Gl.glClear(Gl.GL_COLOR_BUFFER_BIT | Gl.GL_DEPTH_BUFFER_BIT);
        Gl.glLoadIdentity();

        Gl.glPushMatrix();                  // NEW: Prepare Dynamic Transform
        Gl.glMultMatrixf(matrix);           // NEW: Apply Dynamic Transform

        #region plot something
        Gl.glPolygonMode(Gl.GL_FRONT, Gl.GL_FILL);
        Gl.glColor3f(0.8f, 0.3f, 0.1f);
        Gl.glCallList(plot_glList1); // plot using display list 

        //Gl.glPolygonMode(Gl.GL_FRONT, Gl.GL_LINE);
        Gl.glColor3f(0.5f, 0.5f, 0.9f);
        Gl.glCallList(plot_glList2); // plot using display list 

        #endregion plot something

        Gl.glPopMatrix(); // NEW: Unapply Dynamic Transform
        Gl.glFlush();     // Flush the GL Rendering Pipeline

        this.simpleOpenGlControl1.Invalidate();


    }
    catch
    {
        return;
    }
}

I have defined the transformation matrices in here (Arcball.cs):

public class Matrix4f
{

...


    public Quat4f Rotation
    {
        set
        {
            float n, s;
            float xs, ys, zs;
            float wx, wy, wz;
            float xx, xy, xz;
            float yy, yz, zz;

            M = new float[4, 4];

            n = (value.x * value.x) + (value.y * value.y) + 
                (value.z * value.z) + (value.w * value.w);
            s = (n > 0.0f) ? 2.0f / n : 0.0f;

            xs = value.x * s;
            ys = value.y * s;
            zs = value.z * s;
            wx = value.w * xs;
            wy = value.w * ys;
            wz = value.w * zs;
            xx = value.x * xs;
            xy = value.x * ys;
            xz = value.x * zs;
            yy = value.y * ys;
            yz = value.y * zs;
            zz = value.z * zs;

            // rotation
            M[0, 0] = 1.0f - (yy + zz);
            M[0, 1] = xy - wz;
            M[0, 2] = xz + wy;

            M[1, 0] = xy + wz;
            M[1, 1] = 1.0f - (xx + zz);
            M[1, 2] = yz - wx;

            M[2, 0] = xz - wy;
            M[2, 1] = yz + wx;
            M[2, 2] = 1.0f - (xx + yy);

            M[3, 3] = 1.0f;

            // translation (pan)
            M[0, 3] = pan.x;
            M[1, 3] = pan.y;

            // scale (zoom)
            for (int i = 0; i < 3; i++)
                for (int j = 0; j < 3; j++)
                    M[i, j] *= scl;


        }
    }

    public float Scale
    {
        set { scl = value; }

    }

    public Vector3f Pan
    {
        set { pan = value; }

    }

}

You don't need to change anything else and the code should work. I have included comments as much as possible, but feel free to contact me if you have questions.

Note: For almost any code, you do not need to modify the Arcball class at all.

History

  • This is release 1.01. Please let me know if you find any bugs.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

Kam
Engineer
United States United States
No Biography provided

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Comments and Discussions

 
QuestionAsk for help: How can I Rotate Three Dimensional Objects More Faster-based on your Arcball Module in C# Pin
Member 121676871-Dec-15 19:47
memberMember 121676871-Dec-15 19:47 
AnswerRe: Ask for help: How can I Rotate Three Dimensional Objects More Faster-based on your Arcball Module in C# Pin
nightrider1345mins ago
membernightrider1345mins ago 
QuestionAfter translation, rotation and scaling anomaly Pin
Member 1030771720-Nov-13 16:07
memberMember 1030771720-Nov-13 16:07 
QuestionWhy do you use lock? Pin
nightrider138-Feb-13 23:36
membernightrider138-Feb-13 23:36 
QuestionThank you very much , but do you know how to do this kind of graphics Pin
derek091925-Nov-11 21:12
memberderek091925-Nov-11 21:12 
QuestionThank you Pin
Member 819926712-Sep-11 21:18
memberMember 819926712-Sep-11 21:18 
GeneralThanks! Keeping Y axis vertical Pin
norrisMiou27-Feb-11 3:07
membernorrisMiou27-Feb-11 3:07 
GeneralRe: Thanks! Keeping Y axis vertical Pin
Kam3-Mar-11 10:23
memberKam3-Mar-11 10:23 
GeneralRotate camera Pin
sajmon4423-Sep-10 0:30
membersajmon4423-Sep-10 0:30 
GeneralThanks! Pin
LimeMan26-May-10 8:01
memberLimeMan26-May-10 8:01 
GeneralPan is reversed Pin
Rajeev Lochan15-Apr-10 0:06
memberRajeev Lochan15-Apr-10 0:06 
GeneralRe: Pan is reversed Pin
Kam26-Apr-10 20:11
memberKam26-Apr-10 20:11 
GeneralZoom and Viewing directions [modified] Pin
M.Siyamalan19-Mar-10 1:22
memberM.Siyamalan19-Mar-10 1:22 
GeneralRe: Zoom and Viewing directions Pin
Kam30-Mar-10 9:57
memberKam30-Mar-10 9:57 
GeneralInverse Transformation Pin
Member 266410825-Nov-09 19:17
memberMember 266410825-Nov-09 19:17 
GeneralRe: Inverse Transformation Pin
Kam27-Nov-09 19:34
memberKam27-Nov-09 19:34 
Questionhow to implement this in DirectX Pin
Sodrohu1-Oct-09 22:43
memberSodrohu1-Oct-09 22:43 
AnswerRe: how to implement this in DirectX Pin
Kam27-Nov-09 19:35
memberKam27-Nov-09 19:35 
QuestionStandard views Pin
samjoe30-Apr-09 19:32
membersamjoe30-Apr-09 19:32 
AnswerRe: Standard views Pin
Kam11-Jun-09 20:14
memberKam11-Jun-09 20:14 
GeneralExcelent work Pin
TiagoRibeiro23-Apr-09 15:27
memberTiagoRibeiro23-Apr-09 15:27 
GeneralRe: Excelent work Pin
Kam28-Apr-09 18:24
memberKam28-Apr-09 18:24 
GeneralRe: Excelent work Pin
Fransiscus Herry10-Mar-10 20:13
memberFransiscus Herry10-Mar-10 20:13 
QuestionHow can I change the BackColor? Pin
Gerber Samuel27-Mar-09 0:02
memberGerber Samuel27-Mar-09 0:02 
AnswerRe: How can I change the BackColor? Pin
Gerber Samuel27-Mar-09 1:07
memberGerber Samuel27-Mar-09 1:07 
GeneralGood Pin
uaterelelli9-Jan-09 2:52
memberuaterelelli9-Jan-09 2:52 
GeneralRe: Good Pin
Kam21-Jan-09 14:04
memberKam21-Jan-09 14:04 
GeneralRe: Good Pin
Tom Reesbeck8-May-10 10:36
memberTom Reesbeck8-May-10 10:36 
GeneralThank you Pin
bingqilin1-Dec-08 5:42
memberbingqilin1-Dec-08 5:42 
GeneralRe: Thank you Pin
Kam21-Jan-09 14:05
memberKam21-Jan-09 14:05 
GeneralThanks a lot...... Pin
LB Murali Krishna30-Apr-08 8:03
memberLB Murali Krishna30-Apr-08 8:03 
GeneralRe: Thanks a lot...... Pin
Kam30-Apr-08 10:20
memberKam30-Apr-08 10:20 
GeneralMany thanks Pin
SteveAbbott3-Jan-08 6:03
memberSteveAbbott3-Jan-08 6:03 
GeneralRe: Many thanks Pin
Kam3-Jan-08 12:11
memberKam3-Jan-08 12:11 
GeneralCool Pin
Paul Conrad29-Dec-07 10:02
memberPaul Conrad29-Dec-07 10:02 
GeneralNice one Pin
mirano27-Dec-07 8:22
membermirano27-Dec-07 8:22 
GeneralRe: Nice one Pin
Kam28-Dec-07 4:15
memberKam28-Dec-07 4:15 

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