/// <summary>
/// Compares two <see cref="Coordinate" />s for their relative position along a segment
/// lying in the specified <see cref="Octant" />.
/// </summary>
/// <param name="octant"></param>
/// <param name="p0"></param>
/// <param name="p1"></param>
/// <returns>
/// -1 if node0 occurs first, or
/// 0 if the two nodes are equal, or
/// 1 if node1 occurs first.
/// </returns>
public static int Compare(OctantDirection octant, Coordinate p0, Coordinate p1)
{
// nodes can only be equal if their coordinates are equal
if (p0.Equals2D(p1))
return 0;
int xSign = RelativeSign(p0.X, p1.X);
int ySign = RelativeSign(p0.Y, p1.Y);
switch (octant)
{
case OctantDirection.Zero:
return CompareValue(xSign, ySign);
case OctantDirection.One:
return CompareValue(ySign, xSign);
case OctantDirection.Two:
return CompareValue(ySign, -xSign);
case OctantDirection.Three:
return CompareValue(-xSign, ySign);
case OctantDirection.Four:
return CompareValue(-xSign, -ySign);
case OctantDirection.Five:
return CompareValue(-ySign, -xSign);
case OctantDirection.Six:
return CompareValue(-ySign, xSign);
case OctantDirection.Seven:
return CompareValue(xSign, -ySign);
}
throw new InvalidOctantException(octant.ToString());
}
/// <summary>
/// Initializes a new instance of the <see cref="SegmentNode"/> class.
/// </summary>
/// <param name="segString"></param>
/// <param name="coord"></param>
/// <param name="segmentIndex"></param>
/// <param name="segmentOctant"></param>
public SegmentNode(SegmentString segString, Coordinate coord, int segmentIndex, OctantDirection segmentOctant)
{
Coordinate = new Coordinate(coord);
SegmentIndex = segmentIndex;
_segmentOctant = segmentOctant;
_isInterior = !coord.Equals2D(segString.GetCoordinate(segmentIndex));
}
/// <summary>
/// Converts a OctantDirection value to a normalized Vector2.
/// </summary>
/// <param name="direction">OctantDirection value to convert.</param>
/// <returns>A normalized Vector2 instance.</returns>
public static Vector2 DirectionToVector(OctantDirection direction)
{
switch (direction)
{
case OctantDirection.Up:
return(new Vector2(0.0f, -1.0f));
case OctantDirection.UpLeft:
return(new Vector2(-_inverseSqrt2, -_inverseSqrt2));
case OctantDirection.UpRight:
return(new Vector2(_inverseSqrt2, -_inverseSqrt2));
case OctantDirection.Down:
return(new Vector2(0.0f, 1.0f));
case OctantDirection.DownLeft:
return(new Vector2(-_inverseSqrt2, _inverseSqrt2));
case OctantDirection.DownRight:
return(new Vector2(_inverseSqrt2, _inverseSqrt2));
case OctantDirection.Left:
return(new Vector2(-1.0f, 0.0f));
case OctantDirection.Right:
return(new Vector2(1.0f, 0.0f));
default:
return(Vector2.Zero);
}
}
/// <summary>
/// Initializes a new instance of the <see cref="SegmentNode"/> class.
/// </summary>
/// <param name="segString"></param>
/// <param name="coord"></param>
/// <param name="segmentIndex"></param>
/// <param name="segmentOctant"></param>
public SegmentNode(SegmentString segString, Coordinate coord, int segmentIndex, OctantDirection segmentOctant)
{
Coordinate = new Coordinate(coord);
SegmentIndex = segmentIndex;
_segmentOctant = segmentOctant;
_isInterior = !coord.Equals2D(segString.GetCoordinate(segmentIndex));
}
/// <summary>
/// Direction of right thumbstick position on a particular player's gamepad.
/// </summary>
/// <param name="player">Player whose gamepad will be checked.</param>
/// <returns>OctantDirection indicating right thumbstick direction.</returns>
public static OctantDirection GetGamePadRightThumbStickOctantDirection(this InputManager inputManager, PlayerIndex player)
{
OctantDirection direction = OctantDirection.None;
if (_currentGamePadStates[player].IsConnected)
{
direction = _currentGamePadStates[player].ThumbSticks.Right.ToOctantDirection();
}
return(direction);
}
/// <summary>
/// Compares two <see cref="Coordinate" />s for their relative position along a segment
/// lying in the specified <see cref="Octant" />.
/// </summary>
/// <param name="octant"></param>
/// <param name="p0"></param>
/// <param name="p1"></param>
/// <returns>
/// -1 if node0 occurs first, or
/// 0 if the two nodes are equal, or
/// 1 if node1 occurs first.
/// </returns>
public static int Compare(OctantDirection octant, Coordinate p0, Coordinate p1)
{
// nodes can only be equal if their coordinates are equal
if (p0.Equals2D(p1))
{
return(0);
}
int xSign = RelativeSign(p0.X, p1.X);
int ySign = RelativeSign(p0.Y, p1.Y);
switch (octant)
{
case OctantDirection.Zero:
return(CompareValue(xSign, ySign));
case OctantDirection.One:
return(CompareValue(ySign, xSign));
case OctantDirection.Two:
return(CompareValue(ySign, -xSign));
case OctantDirection.Three:
return(CompareValue(-xSign, ySign));
case OctantDirection.Four:
return(CompareValue(-xSign, -ySign));
case OctantDirection.Five:
return(CompareValue(-ySign, -xSign));
case OctantDirection.Six:
return(CompareValue(-ySign, xSign));
case OctantDirection.Seven:
return(CompareValue(xSign, -ySign));
}
throw new InvalidOctantException(octant.ToString());
}
/// <summary>
/// Converts a OctantDirection value to a normalized Vector2.
/// </summary>
/// <param name="direction">OctantDirection value to convert.</param>
/// <returns>A normalized Vector2 instance.</returns>
public static Vector2 DirectionToVector(OctantDirection direction)
{
switch (direction)
{
case OctantDirection.Up:
return new Vector2(0.0f, -1.0f);
case OctantDirection.UpLeft:
return new Vector2(-_inverseSqrt2, -_inverseSqrt2);
case OctantDirection.UpRight:
return new Vector2(_inverseSqrt2, -_inverseSqrt2);
case OctantDirection.Down:
return new Vector2(0.0f, 1.0f);
case OctantDirection.DownLeft:
return new Vector2(-_inverseSqrt2, _inverseSqrt2);
case OctantDirection.DownRight:
return new Vector2(_inverseSqrt2, _inverseSqrt2);
case OctantDirection.Left:
return new Vector2(-1.0f, 0.0f);
case OctantDirection.Right:
return new Vector2(1.0f, 0.0f);
default:
return Vector2.Zero;
}
}
