/// <summary>
/// 履带平铺计算
/// </summary>
private List <TrackChildInfo> ComputeTrackSpread()
{
//find the curve node that is parallel to the circle's right axis
Vector3 midPos, midTangent, midUp;
float midDistance;
circleCurve.GetBottomMidSample(out midPos, out midTangent, out midUp, out midDistance);
Vector3 midForward = Vector3.Cross(midUp, midTangent);
Quaternion midRotation = Quaternion.LookRotation(midForward, midUp);
Vector3 startPos = midPos - midTangent * 0.5f * circleCurve.Length;
Vector3 scale = Scale * Vector3.one;
float distance = 0;
float totalLength = circleCurve.Length;
int index = 0;
while (distance <= totalLength)
{
TrackChildInfo tInfo = new TrackChildInfo();
tInfo.distOnCurve = distance;
tInfo.position = startPos + midTangent * distance + midForward * Deviation;
tInfo.scale = scale;
tInfo.rotation = midRotation;
transInfos.Add(tInfo);
index++;
distance += Spacing;
}
return(transInfos);
}
public List <TrackChildInfo> ComputeTrack()
{
transInfos.Clear();
if (!circleCurve.IsBuilt)
{
circleCurve.Build(Circles, CurveType);
}
if (IsSpread)
{
return(ComputeTrackSpread());
}
float distance = 0;
float totalLength = circleCurve.Length;
int index = 0;
while (distance <= totalLength)
{
Vector3 pos, tangent, up, forward;
float curveDistance = (StartOffset + distance) - totalLength * Mathf.FloorToInt((StartOffset + distance) / totalLength);
circleCurve.GetSampleAtDistance(curveDistance, out pos, out tangent, out up);
TrackChildInfo tInfo = new TrackChildInfo();
tInfo.distOnCurve = curveDistance;
// scale
tInfo.scale = Scale * Vector3.one;
// rotate, get forward from left and up
forward = Vector3.Cross(up, tangent);
tInfo.rotation = Quaternion.LookRotation(forward, up);
// move along spline, according to spacing
tInfo.position = pos + forward * Deviation;
transInfos.Add(tInfo);
index++;
distance += Spacing;
}
return(transInfos);
}
protected override void Create()
{
if (Spacing <= 0 || Prefab == null || Circles == null || Circles.Length == 0)
{
return;
}
ComputeTrack();
int index = 0;
while (index < transInfos.Count)
{
Transform child = null;
if (index >= transform.childCount)
{
GameObject go = Instantiate(Prefab, transform, false);
child = go.transform;
child.name = Prefab.name + "_" + index;
}
else
{
child = transform.GetChild(index);
}
TrackChildInfo tInfo = transInfos[index];
child.position = tInfo.position;
child.rotation = tInfo.rotation;
child.localScale = tInfo.scale;
index++;
}
//delete unused
int startIndex = transform.childCount - 1;
for (int j = startIndex; j >= index; j--)
{
DestroyImmediate(transform.GetChild(j).gameObject);
}
}
