/// <summary>
/// Find the single open note which is closest to the frequency.
/// </summary>
/// <param name="twoClosestOpenNotes">The two open notes that the frequency is between them.</param>
/// <param name="frequency">The given frequency.</param>
/// <returns>Retruns the main note that is being tuned to.</returns>
private Note FindClosestOpenNote(UpperAndLowerNotes twoClosestOpenNotes, Hz frequency)
{
if ((twoClosestOpenNotes.Upper.Hertz - frequency) < (frequency - twoClosestOpenNotes.Lower.Hertz))
{
return(twoClosestOpenNotes.Upper);
}
else
{
return(twoClosestOpenNotes.Lower);
}
}
/// <summary>
/// Finds the two closest open chord notes (as shown at NoteFrequencyFilter description)
/// of the played frequency.
/// </summary>
/// <param name="playedFrequency">The frequency the user played.</param>
/// <returns>Returns the two closest open chord notes,
/// unless the playedFrequency is above the highest open string frequency,
/// or below the lowest open string frequency,
/// in that case it will return the same value for both.</returns>
private UpperAndLowerNotes GetTwoClosestOpenNotes(Hz playedFrequency)
{
UpperAndLowerNotes twoClosestOpenNotes = new UpperAndLowerNotes(Notes.LowerLimit, Notes.UpperLimit);
if (playedFrequency <= OpenStringNotes.E2.Hertz)
{
twoClosestOpenNotes.Lower = Notes.LowerLimit;
twoClosestOpenNotes.Upper = OpenStringNotes.E2;
}
else if (playedFrequency > OpenStringNotes.E2.Hertz && playedFrequency <= OpenStringNotes.A2.Hertz)
{
twoClosestOpenNotes.Lower = OpenStringNotes.E2;
twoClosestOpenNotes.Upper = OpenStringNotes.A2;
}
else if (playedFrequency > OpenStringNotes.A2.Hertz && playedFrequency <= OpenStringNotes.D3.Hertz)
{
twoClosestOpenNotes.Lower = OpenStringNotes.A2;
twoClosestOpenNotes.Upper = OpenStringNotes.D3;
}
else if (playedFrequency > OpenStringNotes.D3.Hertz && playedFrequency <= OpenStringNotes.G3.Hertz)
{
twoClosestOpenNotes.Lower = OpenStringNotes.D3;
twoClosestOpenNotes.Upper = OpenStringNotes.G3;
}
else if (playedFrequency > OpenStringNotes.G3.Hertz && playedFrequency <= OpenStringNotes.B3.Hertz)
{
twoClosestOpenNotes.Lower = OpenStringNotes.G3;
twoClosestOpenNotes.Upper = OpenStringNotes.B3;
}
else if (playedFrequency > OpenStringNotes.B3.Hertz && playedFrequency <= OpenStringNotes.E4.Hertz)
{
twoClosestOpenNotes.Lower = OpenStringNotes.B3;
twoClosestOpenNotes.Upper = OpenStringNotes.E4;
}
else if (playedFrequency > OpenStringNotes.E4.Hertz)
{
twoClosestOpenNotes.Lower = OpenStringNotes.E4;
twoClosestOpenNotes.Upper = Notes.UpperLimit;
}
return(twoClosestOpenNotes);
}
public Note FindClosestNote(Hz frequency)
{
float currentDifference, prevDifference = Notes.UpperLimit.Hertz;
Note tempNote = null;
foreach (Note note in _notesArray)
{
currentDifference = Math.Abs(note.Hertz - frequency);
if (currentDifference < prevDifference)
{
tempNote = note;
}
else
{
break;
}
prevDifference = currentDifference;
}
return(tempNote);
}
/// <summary>
/// Open string notes:
/// String Frequency Scientific pitch notation
/// 1 (E) 329.63 Hz E4
/// 82.69? / 2 = 41.345
/// 2 (B) 246.94 Hz B3
/// 50.94? / 2 = 25.470
/// 3 (G) 196.00 Hz G3
/// 49.17? / 2 = 24.585
/// 4 (D) 146.83 Hz D3
/// 36.83? / 2 = 18.415
/// 5 (A) 110.000 Hz A2
/// 27.59? / 2 = 13.795
/// 6 (E) 82.407 Hz E2
///
/// The filter is responsible for routing the note that is being recieved to its place.
/// </summary>
/// <param name="frequency">The note's frequency represented by a number.</param>
/// <returns></returns>
public NoteDifference NoteFrequencyFilter(Hz frequency)
{
//Determine frequency range. (Get 2 closest open notes that the frequency is between them).
UpperAndLowerNotes twoClosestOpenNotes = GetTwoClosestOpenNotes(frequency);
//Assume a closest note.
//Note closestNote = twoClosestOpenNotes.Upper;
//If the two closest notes are actually diffrent ones, then...
//if (twoClosestOpenNotes.Upper != twoClosestOpenNotes.Lower)
//Find which out of the two closest notes the played frequency is closer to.
Note closestNote = FindClosestOpenNote(twoClosestOpenNotes, frequency);
//Find out how close the played frequency is from its closest note by percetage.
//NoteDifference noteDifference =
return(CalculateRatioOfCloseness(twoClosestOpenNotes, closestNote, frequency));
//Get the closest note for presentation.
//string noteNameRepresentation = string.Empty;
//noteDifference.ClosestNote = closestNote.Name; //noteNameRepresentation;
//return noteDifference;
}
/// <summary>
/// Gets the distance between the played frequency to the open note by percentage.
/// </summary>
/// <param name="twoClosestOpenNotes">The two closest open notes to the frequency.</param>
/// <param name="closestNote">The most closest note, out of the two closest notes,
/// which will be used as a reference to calculate the difference between this and the playedFrequency.</param>
/// <param name="playedFrequency">The note that the user hits translated to frequency [Hz].</param>
/// <returns>How close the users' frequency is from the desired note.</returns>
private NoteDifference CalculateRatioOfCloseness(UpperAndLowerNotes twoClosestOpenNotes, Note closestNote, Hz playedFrequency)
{
float closenessToMark; //Closeness to the exact note mark. Number between 0 and 1.
NoteDifference noteDiff = new NoteDifference();
//Represents how close the frequency is from the closestNote.
float difference = Math.Abs(playedFrequency - closestNote.Hertz);
float middleOfTwoOpenNotes = Math.Abs(twoClosestOpenNotes.Upper.Hertz - twoClosestOpenNotes.Lower.Hertz) / 2;
if (middleOfTwoOpenNotes != 0)
{
//Calculate the closness to the closestNote.
closenessToMark = difference / middleOfTwoOpenNotes; //FIX: Why is that?
}
else
{
closenessToMark = difference;
}
//Calculate the alpha (opacity) of the note indicator.
//noteDiff.ClosnessAlpha = NoteDifference.FULL_ALPHA - closenessToMark;
//Calculate the closness by a precentage of base 90.
noteDiff.ClosnessByPercentage_Base90 = closenessToMark * 90; //FIX: This is not a precentage!
noteDiff.ClosestNote = closestNote.Name;
if (playedFrequency < closestNote.Hertz)
{
//from -90 to 0 degrees.
noteDiff.ClosnessByPercentage_Base90 *= (-1);
//if (closestNote.Alias != null)
// noteDiff.ClosestNote = closestNote.Alias;
}
return(noteDiff);
}
