Re: OpenAL .. Directional Effects .. Need Help

On Thursday, January 20, 2011 12:59:16 am Cherukuri Jyothi Swaroop wrote:
> Hi
> 
> I ported OpenAL to our platform and able to play the wav files.
> I wrote a sample openal application and try to produce some sound effects.
> Play back of audio is working but sound effects are not working.
> 
> I am using jungle.wav which is mono channel sound wave file as input

...

> I am expecting the sound to be played in the right headphone/speaker.
> 
> But the sound is played in both the headphones.

Hi.

I think the cause is here:

    SourcesPos[0] = 200;
    SourcesPos[1] = 200;
    SourcesPos[2] = 25;

This sets the source to the right side, but also high up and a bit behind the 
listener. This causes the sound to pan towards the center since it's not 
strictly on the right side. It shouldn't be perfectly centered (it should be a 
bit less than half way to the right), but it does make OpenAL produce sound on 
the left speaker as well as the right. If you set that to:

    SourcesPos[0] = 200;
    SourcesPos[1] = 0;
    SourcesPos[2] = 0;

Does it play on the right side that way? If so, that's just how the panning 
algorithm works. The farther a source is from a strict right position, the 
more it pans towards the left so it can make a smooth transition as it circles 
around the listener.


Also, on a side note:

    alGenBuffers(NUM, Buffers);
    Buffer[0]= alutCreateBufferFromFile("/Res/jungle.wav");

This is causing a leak. alGenBuffers creates NUM buffer IDs and writes them to 
the Buffers array, but alutCreateBufferFromFile is creating another buffer ID 
and overwriting Buffers[0]. The Buffers[0] that alGenBuffers created is lost, 
replaced by the one alutCreateBufferFromFile created.


Hope that helps. :)
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