public static SKMatrix44 CreateRotationDegrees(float x, float y, float z, float degrees)
{
var matrix = new SKMatrix44();
matrix.SetRotationAboutDegrees(x, y, z, degrees);
return(matrix);
}
/// <summary>
/// Updates the particle's position and orientation based on the given time
/// </summary>
/// <para>Call this method first and then <see cref="Paint"/></para>
/// <para>This method doesn't need to be called on the UI/Main thread</para>
/// <param name="absoluteElapsedMillis"></param>
public virtual void Update(long absoluteElapsedMillis, SKSize scale)
{
// Determine elapsed time since this particles was created
var elapsedMillis = absoluteElapsedMillis - _absoluteElapsedMillisPrevious;
if (_absoluteElapsedMillisPrevious == 0)
{
_absoluteElapsedMillisPrevious = absoluteElapsedMillis;
return;
}
_internalAbsoluteMillis += elapsedMillis;
_absoluteElapsedMillisPrevious = absoluteElapsedMillis;
// Traversed distance = speed x time
var dist = TranslationSpeed * _internalAbsoluteMillis * 0.001;
// New position
var deg2radFactor = 0.0174533;
var angle = Direction * deg2radFactor;
Position = InitialPosition + new SKPoint
{
X = (float)(dist * Math.Cos(angle)),
Y = (float)(dist * Math.Sin(angle))
};
TransformationMatrix = SKMatrix.CreateTranslation(-Position.X, -Position.Y);
// New Scale
TransformationMatrix = TransformationMatrix.PostConcat(SKMatrix.CreateScale(scale.Width, scale.Height));
// New Orientation
Orientation = InitialOrientation + new SKPoint3
{
X = _internalAbsoluteMillis * 0.001f * RotationSpeed.X,
Y = _internalAbsoluteMillis * 0.001f * RotationSpeed.Y,
Z = _internalAbsoluteMillis * 0.001f * RotationSpeed.Z
};
_totalRotationMatrix.SetIdentity();
_xAxisRotationMatrix.SetRotationAboutDegrees(1, 0, 0, Orientation.X);
_totalRotationMatrix.PostConcat(_xAxisRotationMatrix);
_yAxisRotationMatrix.SetRotationAboutDegrees(0, 1, 0, Orientation.Y);
_totalRotationMatrix.PostConcat(_yAxisRotationMatrix);
_zAxisRotationMatrix.SetRotationAboutDegrees(0, 0, 1, Orientation.Z);
_totalRotationMatrix.PostConcat(_zAxisRotationMatrix);
TransformationMatrix = TransformationMatrix.PostConcat(_totalRotationMatrix.Matrix);
// Translate back
TransformationMatrix = TransformationMatrix.PostConcat(SKMatrix.CreateTranslation(Position.X, Position.Y));
}