Method SoundSetWaveVolume

Source/script2.cpp:8521–8564

ResultType Line::SoundSetWaveVolume(char *aVolume, HWAVEOUT aDeviceID)
{
	double volume = ATOF(aVolume);
	if (volume < -100)
		volume = -100;
	else if (volume > 100)
		volume = 100;

	// Make this an int vs. WORD so that negative values are supported (e.g. adjust volume by -10%).
	int specified_vol_per_channel = (int)(0xFFFF * (volume / 100));
	DWORD vol_new;

	// For v1.0.25, the first char of RAW_ARG is also checked in case this is an expression intended
	// to be a positive offset, such as +(var + 10)
	if (*aVolume == '-' || *aVolume == '+' || *RAW_ARG1 == '+') // User wants to adjust the current level by a certain amount.
	{
		DWORD current_vol;
		if (waveOutGetVolume(aDeviceID, &current_vol) != MMSYSERR_NOERROR)
			return g_ErrorLevel->Assign(ERRORLEVEL_ERROR);
		// Adjust left & right independently so that we at least attempt to retain the user's
		// balance setting (if overflow or underflow occurs, the relative balance might be lost):
		int vol_left = LOWORD(current_vol); // Make them ints so that overflow/underflow can be detected.
		int vol_right = HIWORD(current_vol);
		vol_left += specified_vol_per_channel;
		vol_right += specified_vol_per_channel;
		// Handle underflow or overflow:
		if (vol_left < 0)
			vol_left = 0;
		else if (vol_left > 0xFFFF)
			vol_left = 0xFFFF;
		if (vol_right < 0)
			vol_right = 0;
		else if (vol_right > 0xFFFF)
			vol_right = 0xFFFF;
		vol_new = MAKELONG((WORD)vol_left, (WORD)vol_right);  // Left is low-order, right is high-order.
	}
	else // User wants the volume level set to an absolute level (i.e. ignore its current level).
		vol_new = MAKELONG((WORD)specified_vol_per_channel, (WORD)specified_vol_per_channel);

	if (waveOutSetVolume(aDeviceID, vol_new) == MMSYSERR_NOERROR)
		return g_ErrorLevel->Assign(ERRORLEVEL_NONE);
	else
		return g_ErrorLevel->Assign(ERRORLEVEL_ERROR);
}