irrKlang tutorial: 3D Sound (C#)

This example will show how how to play sounds in 3D space using irrKlang. An mp3 file file be played in 3D space and moved around the user and a sound will be played at a random 3D position every time the user presses a key.

Let's start

At the beginning, we simply create a class and add the namespace IrrKlang in which all sound engine classes are located.

using System;
using IrrKlang;

namespace CSharp._02._3DSound
{
  class Class1
  {
    [STAThread]
    static void Main(string[] args)
    {

Now lets start with irrKlang 3D sound engine example 02, demonstrating 3D sound. Start up the sound engine by creating an instance of the class ISoundEngine. You can specify several options as parameters when invoking that constructor, but for this example, the default parameters are enough. There is nothing more to do when using 3D sound, it's just the same as with 2D sound.

    // start the sound engine with default parameters
			
    ISoundEngine engine = new ISoundEngine();

Now play some sound stream as music in 3d space, looped. We play it at position (0,0,0) in 3d space.

    ISound music = engine.Play3D("../../media/ophelia.mp3",
                                  0,0,0, true);

The following step isn't necessary, but to adjust the distance where the 3D sound can be heard, we set some nicer minimum distance (the default min distance is 1, for a small object). The minimum distance simply is the distance in which the sound gets played at maximum volume.

    if (music != null)
       music.MinDistance = 5.0f;

Print some help text and start the display loop:

    // Print some help text and start the display loop

    Console.Out.Write("\nPlaying streamed sound in 3D.");
    Console.Out.Write("\nPress ESCAPE to quit, any other key to play sound at random position.\n\n");

    Console.Out.Write("+ = Listener position\n");
    Console.Out.Write("o = Playing sound\n");

    Random rand = new Random(); // we need random 3d positions
    const float radius = 5;
    float posOnCircle = 0;

    while(true) // endless loop until user exits
    {

Each step we calculate the position of the 3D music. For this example, we let the music position rotate on a circle:

      posOnCircle += 0.04f;
      Vector3D pos3d = new Vector3D(radius * 
                (float)Math.Cos(posOnCircle), 0,
                radius * (float)Math.Sin(posOnCircle * 0.5f));

After we know the positions, we need to let irrKlang know about the listener position (always position (0,0,0), facing forward in this example: 0,0,1) and let irrKlang know about our calculated 3D music position

      engine.SetListenerPosition(0,0,0, 0,0,1);

      if (music != null)
          music.Position = pos3d;

Now print the position of the sound in a nice way to the console and also print the play position.

      string stringForDisplay = "          +         ";
      int charpos = (int)((pos3d.X + radius) / radius * 10.0f);
      if (charpos >= 0 && charpos < 20)
      {
        stringForDisplay = stringForDisplay.Remove(charpos, 1);
        stringForDisplay = stringForDisplay.Insert(charpos, "o");					
      }

      uint playPos = 0;
      if (music != null)
        playPos = music.PlayPosition;

      string output = String.Format("\rx:({0})   3dpos: {1:f} {2:f} {3:f}, playpos:{4}:{5:00}    ",
                              stringForDisplay, pos3d.X, pos3d.Y, pos3d.Z,
                              playPos/60000, (playPos%60000)/1000);

      Console.Write(output);

      System.Threading.Thread.Sleep(100);

Handle user input: Every time the user presses a key in the console, play a random sound or exit the application if he pressed ESCAPE.

      if (_kbhit()!=0)
      {
        int key = _getch();

        if (key == 27)
          break; // user pressed ESCAPE key
        else
        {

Play random sound at some random position.

        // Play random sound at some random position.

        Vector3D pos = new Vector3D(((float)rand.NextDouble() % radius*2.0f) - radius, 0, 0);

        string filename;

        if (rand.Next()%2 != 0)
          filename = "../../media/bell.wav";
        else
          filename = "../../media/explosion.wav";

        engine.Play3D(filename, pos.X, pos.Y, pos.Z);

        Console.Write("\nplaying {0} at {1:f} {2:f} {3:f}\n",
                       filename, pos.X, pos.Y, pos.Z);

Basically, that's it. The following code just closes the classes and namespace and adds a method _getch() and _kbhit() to read from the console, but this has nothing to do with irrKlang.

        }
      }
    }
  }

  // simple functions for reading keys from the console
  [System.Runtime.InteropServices.DllImport("msvcrt")]
  static extern int _kbhit();
  [System.Runtime.InteropServices.DllImport("msvcrt")]
  static extern int _getch();
  
  }
}

That's it, have fun playing your own sounds in 3D now.
Download tutorial source and binary (included in the SDK)