// 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; }