internal void Update(RtsCameraController camera, GameTime gameTime)
{
var currentTimeFraction = (float)((gameTime.TotalGameTime - _startTime).TotalSeconds / _duration.TotalSeconds);
currentTimeFraction = Math.Min(currentTimeFraction, 1);
var pos = currentTimeFraction * (_points.Count - 1);
var integralPart = (int)Math.Truncate(pos);
var decimalPart = pos - integralPart;
// TODO: Not sure how right this is
// Near the end of the path 2-3 points are the same, so the movement becomes more linear?
var point1 = integralPart;
var point2 = Math.Min(point1 + 1, _points.Count - 1);
var point0 = Math.Max(point1 - 1, 0);
var point3 = Math.Min(point2 + 1, _points.Count - 1);
camera.TerrainPosition = Interpolation.CatmullRom(
_points[point0],
_points[point1],
_points[point2],
_points[point3],
decimalPart);
if (_lookToward != null)
{
var lookDirection = Vector3.Normalize(_lookToward.Value - camera.TerrainPosition);
camera.SetLookDirection(lookDirection);
}
else if (_endDirection != null)
{
var lookDirection = Vector3.Normalize(Vector3Utility.Slerp(_startDirection, _endDirection.Value, currentTimeFraction));
camera.SetLookDirection(lookDirection);
}
if (_endPitch != null)
{
var pitch = MathUtility.Lerp(_startPitch, _endPitch.Value, currentTimeFraction);
camera.Pitch = pitch;
}
if (_endZoom != null)
{
var zoom = MathUtility.Lerp(_startZoom, _endZoom.Value, currentTimeFraction);
camera.Zoom = zoom;
}
if (gameTime.TotalGameTime > _endTime)
{
Finished = true;
}
}