Sound emmiters with panning and volume in 2D

Question

How can I create sound emmiters that pan and change volume based on distance from the player in a 2D game?

Answer 1

Use SoundEffect.CreateInstance(); to get a SoundEffectInstance of your chosen sound effect.

You can then Play() that instance while modifying its Volume and Pan properties.

Or, if it's a short, one-shot sound effect, you can simply use SoundEffect.Play(volume, pitch, pan); to play it at your chosen volume and panning.

Here is some code that I have used in the past to set the volume and panning of a SoundEffectInstance based on the emitting object's position and the camera:

public bool SetSoundForCamera(SoundEffectInstance sound, Vector2 position, float baseVolume)
{
    Vector2 screenDistance = (position-cameraCenter) / cameraHalfSize;
    float fade = MathHelper.Clamp(2f - screenDistance.Length(), 0, 1);
    sound.Volume = fade * fade * baseVolume;
    sound.Pan = MathHelper.Clamp(screenDistance.X, -1, 1);
    return fade > 0;
}

For a SoundEffectInstance, simply call that each frame while the sound is playing. You could extract the maths and use it for one-shot sounds as well.

Of course, for a 2D game, how quickly you pan and how quickly you fade out sounds as they go off screen will depend on your game. You should modify the maths to suit your own game's mood.

Answer 2

There is a 3D audio example on XNA's app hub. I'm pretty sure you can take the same concept for 2D.