// 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) { segLast = seg; seg = s; DateTime cur = DateTime.Now; double fMs = cur.Subtract(timeLastUpdated).TotalMilliseconds; if (fMs < 10.0) fMs = 10.0; double fFPS = 1000.0 / fMs; timeLastUpdated = cur; if (seg.IsCircle()) { xVel = xVel * smoothing + (1.0 - smoothing) * (seg.x1 - segLast.x1) * fFPS; yVel = yVel * smoothing + (1.0 - smoothing) * (seg.y1 - segLast.y1) * fFPS; } else { xVel = xVel * smoothing + (1.0 - smoothing) * (seg.x1 - segLast.x1) * fFPS; yVel = yVel * smoothing + (1.0 - smoothing) * (seg.y1 - segLast.y1) * fFPS; xVel2 = xVel2 * smoothing + (1.0 - smoothing) * (seg.x2 - segLast.x2) * fFPS; yVel2 = yVel2 * smoothing + (1.0 - smoothing) * (seg.y2 - segLast.y2) * fFPS; } }
// 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 Point ptHitCenter, ref double lineHitLocation) { double minDxSquared = size + seg.radius; minDxSquared *= minDxSquared; // See if falling thing hit this body segment if (seg.IsCircle()) { if (SquaredDistance(center.X, center.Y, seg.x1, seg.y1) <= minDxSquared) { ptHitCenter.X = seg.x1; ptHitCenter.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(center.X, center.Y, seg.x1, seg.y1) < minDxSquared) ? true : false; } else { // Find dx from center to line double u = ((center.X - seg.x1) * (seg.x2 - seg.x1) + (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 xIntersect = seg.x1 + (seg.x2 - seg.x1) * u; double yIntersect = seg.y1 + (seg.y2 - seg.y1) * u; if (SquaredDistance(center.X, center.Y, xIntersect, yIntersect) < minDxSquared) { lineHitLocation = u; ptHitCenter.X = xIntersect; ptHitCenter.Y = yIntersect; ; return true; } } else { // See how close we are to an endpoint if (u < 0) { if (SquaredDistance(center.X, center.Y, seg.x1, seg.y1) < minDxSquared) { lineHitLocation = 0; ptHitCenter.X = seg.x1; ptHitCenter.Y = seg.y1; return true; } } else { if (SquaredDistance(center.X, center.Y, seg.x2, seg.y2) < minDxSquared) { lineHitLocation = 1; ptHitCenter.X = seg.x2; ptHitCenter.Y = seg.y2; return true; } } } } return false; } return false; }
public BoneData(Segment s) { seg = segLast = s; xVel = yVel = 0; xVel2 = yVel2 = 0; timeLastUpdated = DateTime.Now; }