问题
So I have been looking around for some time now on a way to produce a variable tone on the iPhone using OpenAL, the issue being the Apple has deprecated the ALUT part of OpenAL that has the alutCreateBufferWaveform that would be perfect for this. I was wondering if anyone had any idea how to make a tone generator using OpenAL on the iPhone SDK. All I need is the ability to produce a certain frequency tone consistantly over and over again.
This is a last resort so sorry if it sounds kind of stupid.
回答1:
This isn't exactly what you are looking for, but it can create a similar effect.
I used this tutorial
http://benbritten.com/2008/11/06/openal-sound-on-the-iphone/
to create an engine that could play a prerecorded sound at different levels. So even though I have to play the sound from an existing *.caf file, I can modulate the pitch and control looping so it produces any frequency, length, or volume I'm looking for.
来源：https://stackoverflow.com/questions/2551764/openal-tone-generation-on-iphone