/*
* Gets the value of system sound voulume.
*
* @return
* The value of system sound voulume.
* range of volume is 0.0 .. 1.0.
* @example
* System::Sound.volume
*/
static VALUE
rb_sys_volume(VALUE obj)
{
AudioDeviceID device;
OSStatus err;
UInt32 size;
UInt32 channels[2];
float volume[2];
float b_vol = 0.0;
// get device
device = get_audio_device_id();
// try set master volume (channel 0)
size = sizeof(b_vol);
err = AudioDeviceGetProperty(device, 0, 0, kAudioDevicePropertyVolumeScalar, &size, &b_vol);
if (err == noErr) {
goto EXIT;
}
// otherwise, try seperate channels
// get channel numbers
size = sizeof(channels);
err = AudioDeviceGetProperty(device, 0, 0,kAudioDevicePropertyPreferredChannelsForStereo, &size, &channels);
if (err != noErr) {
rb_raise(rb_eRuntimeError, "Failed to get channel numbers");
}
size = sizeof(float);
err = AudioDeviceGetProperty(device, channels[0], 0, kAudioDevicePropertyVolumeScalar, &size, &volume[0]);
if (err != noErr) {
rb_raise(rb_eRuntimeError, "Failed to get volume of channel");
}
err = AudioDeviceGetProperty(device, channels[1], 0, kAudioDevicePropertyVolumeScalar, &size, &volume[1]);
if (err != noErr) {
rb_raise(rb_eRuntimeError, "Failed to get volume of channel");
}
b_vol = (volume[0] + volume[1]) / 2.0;
EXIT:
return DOUBLE2NUM(b_vol);
}
PRIMITIVE VALUE
vm_double_to_rval(double d)
{
return DOUBLE2NUM(d);
}
PRIMITIVE VALUE
vm_float_to_rval(float f)
{
return DOUBLE2NUM(f);
}
