// Update the segment's position and compute a smoothed velocity for the circle or the
// endpoints of the segment based on the time it took it to move from the last position
// to the current one. The velocity is in pixels per second.
public void UpdateSegment(Segment s)
{
this.LastSegment = this.Segment;
this.Segment = s;
DateTime cur = DateTime.Now;
double fMs = cur.Subtract(this.TimeLastUpdated).TotalMilliseconds;
if (fMs < 10.0)
{
fMs = 10.0;
}
double fps = 1000.0 / fMs;
this.TimeLastUpdated = cur;
if (this.Segment.IsCircle())
{
this.XVelocity = (this.XVelocity * Smoothing) + ((1.0 - Smoothing) * (this.Segment.X1 - this.LastSegment.X1) * fps);
this.YVelocity = (this.YVelocity * Smoothing) + ((1.0 - Smoothing) * (this.Segment.Y1 - this.LastSegment.Y1) * fps);
}
else
{
this.XVelocity = (this.XVelocity * Smoothing) + ((1.0 - Smoothing) * (this.Segment.X1 - this.LastSegment.X1) * fps);
this.YVelocity = (this.YVelocity * Smoothing) + ((1.0 - Smoothing) * (this.Segment.Y1 - this.LastSegment.Y1) * fps);
this.XVelocity2 = (this.XVelocity2 * Smoothing) + ((1.0 - Smoothing) * (this.Segment.X2 - this.LastSegment.X2) * fps);
this.YVelocity2 = (this.YVelocity2 * Smoothing) + ((1.0 - Smoothing) * (this.Segment.Y2 - this.LastSegment.Y2) * fps);
}
}
// Hit testing between this thing and a single segment. If hit, the center point on
// the segment being hit is returned, along with the spot on the line from 0 to 1 if
// a line segment was hit.
public bool Hit(Segment seg, ref System.Windows.Point hitCenter, ref double lineHitLocation)
{
double minDxSquared = this.Size + seg.Radius;
minDxSquared *= minDxSquared;
// See if falling thing hit this body segment
if (seg.IsCircle())
{
if (SquaredDistance(this.Center.X, this.Center.Y, seg.X1, seg.Y1) <= minDxSquared)
{
hitCenter.X = seg.X1;
hitCenter.Y = seg.Y1;
lineHitLocation = 0;
return true;
}
}
else
{
double sqrLineSize = SquaredDistance(seg.X1, seg.Y1, seg.X2, seg.Y2);
if (sqrLineSize < 0.5)
{
// if less than 1/2 pixel apart, just check dx to an endpoint
return SquaredDistance(this.Center.X, this.Center.Y, seg.X1, seg.Y1) < minDxSquared;
}
// Find dx from center to line
double u = ((this.Center.X - seg.X1) * (seg.X2 - seg.X1)) + (((this.Center.Y - seg.Y1) * (seg.Y2 - seg.Y1)) / sqrLineSize);
if ((u >= 0) && (u <= 1.0))
{ // Tangent within line endpoints, see if we're close enough
double intersectX = seg.X1 + ((seg.X2 - seg.X1) * u);
double intersectY = seg.Y1 + ((seg.Y2 - seg.Y1) * u);
if (SquaredDistance(this.Center.X, this.Center.Y, intersectX, intersectY) < minDxSquared)
{
lineHitLocation = u;
hitCenter.X = intersectX;
hitCenter.Y = intersectY;
return true;
}
}
else
{
// See how close we are to an endpoint
if (u < 0)
{
if (SquaredDistance(this.Center.X, this.Center.Y, seg.X1, seg.Y1) < minDxSquared)
{
lineHitLocation = 0;
hitCenter.X = seg.X1;
hitCenter.Y = seg.Y1;
return true;
}
}
else
{
if (SquaredDistance(this.Center.X, this.Center.Y, seg.X2, seg.Y2) < minDxSquared)
{
lineHitLocation = 1;
hitCenter.X = seg.X2;
hitCenter.Y = seg.Y2;
return true;
}
}
}
return false;
}
return false;
}
public BoneData(Segment s)
{
this.Segment = this.LastSegment = s;
this.XVelocity = this.YVelocity = 0;
this.XVelocity2 = this.YVelocity2 = 0;
this.TimeLastUpdated = DateTime.Now;
}
