public Vector3[] CalculateEvenlySpacedPoints(float spacing, float resolution = 1)
{
List <Vector3> evenlySpacedPoints = new List <Vector3>();
evenlySpacedPoints.Add(points[0]);
Vector3 previousPoint = points[0];
float dstSinceLastEvenPoint = 0;
for (int segmentIndex = 0; segmentIndex < SegmentCount; segmentIndex++)
{
Vector3[] p = GetPointsInSegment(segmentIndex);
float controlNetLength = Vector3.Distance(p[0], p[1]) + Vector3.Distance(p[1], p[2])
+ Vector3.Distance(p[2], p[3]);
float estimatedCurveLength = Vector3.Distance(p[0], p[3]) + controlNetLength * 0.5f;
int division = Mathf.CeilToInt(estimatedCurveLength * resolution * 10);
float t = 0;
while (t <= 1f)
{
t += 1f / division;
Vector3 pointOnCurve = Bezier.CalculateCubic(p[0], p[1], p[2], p[3], t);
dstSinceLastEvenPoint += Vector3.Distance(previousPoint, pointOnCurve);
while (dstSinceLastEvenPoint >= spacing)
{
float overShootDistance = dstSinceLastEvenPoint - spacing;
Vector3 newEvenlySpacedPoint = pointOnCurve + (previousPoint - pointOnCurve).normalized * overShootDistance;
evenlySpacedPoints.Add(newEvenlySpacedPoint);
dstSinceLastEvenPoint = overShootDistance;
previousPoint = newEvenlySpacedPoint;
}
previousPoint = pointOnCurve;
}
}
return(evenlySpacedPoints.ToArray());
}
/// <summary>
/// 计算平均放置点的位置
/// </summary>
/// <param name="spacing"></param>
/// <param name="resolution"></param>
/// <returns></returns>
public Vector2[] CalculateEvenlySpacedPoints(float spacing, float resolution = 1)
{
List <Vector2> evenlySpacedPoints = new List <Vector2> {
points[0]
};
//前一个点
Vector2 prePoint = points[0];
//这个点到上个平均放置点的距离
float sinceLastEvenPointDistance = 0;
for (int segmentIndex = 0; segmentIndex < NumSegments; segmentIndex++)
{
Vector2[] segmentPoints = GetPointsInSegment(segmentIndex);
//锚点和控制点构成的三条线段的长度
float controlPointsLineLength = Vector2.Distance(segmentPoints[0], segmentPoints[1]) +
Vector2.Distance(segmentPoints[1], segmentPoints[2]) + Vector2.Distance(segmentPoints[2], segmentPoints[3]);
//估算的贝塞尔曲线长度:锚点间距+锚点和控制点构成的三条线段的一半
float estimatedCurveLength = Vector2.Distance(segmentPoints[0], segmentPoints[3]) + controlPointsLineLength / 2f;
int divisons = Mathf.CeilToInt(estimatedCurveLength * resolution * 10);
float t = 0;
while (t <= 1)
{
t += 1f / divisons;
//采样点
Vector2 pointOnCurve = Bezier.CalculateCubic(segmentPoints[0], segmentPoints[1], segmentPoints[2],
segmentPoints[3], t);
sinceLastEvenPointDistance += Vector2.Distance(prePoint, pointOnCurve);
//如果距离超过了期望的平均点位置
while (sinceLastEvenPointDistance >= spacing)
{
//记录期望平均点位置
float offset = sinceLastEvenPointDistance - spacing;
Vector2 direction = (prePoint - pointOnCurve).normalized;
Vector2 addEvenlyPoint = pointOnCurve + direction * offset;
evenlySpacedPoints.Add(addEvenlyPoint);
sinceLastEvenPointDistance = offset;
prePoint = addEvenlyPoint;
}
prePoint = pointOnCurve;
}
}
return(evenlySpacedPoints.ToArray());
}
public Vector3 GetPoint(float t)
{
int i; // segment index
if (t >= 1f)
{
t = 1f;
i = points.Count - 4;
}
else
{
t = Mathf.Clamp01(t) * SegmentCount;
i = (int)t;
t -= i;
i *= 3;
}
return(Bezier.CalculateCubic(points[i], points[i + 1], points[i + 2], points[i + 3], t));
}
protected override void UpdateTrail(TrailGraphics trail, float deltaTime)
{
if (!trail.activeSelf)
{
return;
}
int trailPointIdx = 0;
for (int i = 0; i < controlPoints.Count; i++)
{
trail.points[trailPointIdx].position = controlPoints[i].position;
trail.points[trailPointIdx].forwardDirection = controlPoints[i].forward;
trailPointIdx++;
if (i < controlPoints.Count - 1)
{
Vector3 cp1, cp2;
float distance = Vector3.Distance(controlPoints[i].position, controlPoints[i + 1].position) / 2;
if (i == 0)
{
cp1 = controlPoints[i].position + (controlPoints[i + 1].position - controlPoints[i].position).normalized * distance;
}
else
{
cp1 = controlPoints[i].position + (controlPoints[i + 1].position - controlPoints[i - 1].position).normalized * distance;
}
int nextIdx = i + 1;
if (nextIdx == controlPoints.Count - 1)
{
cp2 = controlPoints[nextIdx].position + (controlPoints[nextIdx - 1].position - controlPoints[nextIdx].position).normalized * distance;
}
else
{
cp2 = controlPoints[nextIdx].position + (controlPoints[nextIdx - 1].position - controlPoints[nextIdx + 1].position).normalized * distance;
}
TrailPoint current = trail.points[trailPointIdx - 1];
TrailPoint next = trail.points[trailPointIdx + pointsInMiddle];
for (int j = 0; j < pointsInMiddle; j++)
{
float t = (((float)j + 1) / ((float)pointsInMiddle + 1));
trail.points[trailPointIdx].position = Bezier.CalculateCubic(t, controlPoints[i].position, cp1, cp2, controlPoints[i + 1].position);
trail.points[trailPointIdx].timeSoFar = Mathf.Lerp(current.timeSoFar, next.timeSoFar, t);
trail.points[trailPointIdx].forwardDirection = Vector3.Lerp(current.forwardDirection, next.forwardDirection, t);
trailPointIdx++;
}
}
}
int lastCPIdx = (pointsInMiddle + 1) * (controlPoints.Count - 1);
int prevCPIdx = lastCPIdx - pointsInMiddle - 1;
int activeCount = lastCPIdx + 1;
float distance2Src = trail.points[prevCPIdx].distance2Src;
for (int i = prevCPIdx + 1; i < activeCount; i++)
{
distance2Src += Vector3.Distance(trail.points[i - 1].position, trail.points[i].position);
trail.points[i].distance2Src = distance2Src;
}
}
