Files
FlyShotHost/src/Flyshot.ControllerClientCompat/ControllerClientTrajectoryOrchestrator.cs
yunxiao.zhu 74761bb5da feat(flyshot): 引入飞拍执行侧最终发送队列构建与校验机制
* 新增 FlyshotExecutionSendSequenceBuilder,负责在运行时前构建最终 8ms 发送队列,并进行离散限幅校验。
* 引入 FlyshotPreparedExecution 类,封装最终发送结果及相关诊断信息。
* 调整 ControllerClientCompatService 和 FanucControllerRuntime,确保运行时直接使用预生成的发送队列,避免临场重采样。
* 更新 TrajectoryResult 和 PlannedExecutionBundle,支持准备好的执行队列。
* 增加单元测试,验证非 1 倍 speedRatio 下的执行行为与预生成队列的使用。
2026-05-09 19:06:49 +08:00

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using Flyshot.Core.Config;
using Flyshot.Core.Domain;
using Flyshot.Core.Planning;
using Flyshot.Core.Planning.Sampling;
using Flyshot.Core.Triggering;
using Microsoft.Extensions.Logging;
namespace Flyshot.ControllerClientCompat;
/// <summary>
/// 负责把 ControllerClient 兼容层的轨迹输入转换为规划结果和触发时间轴。
/// </summary>
public sealed class ControllerClientTrajectoryOrchestrator
{
/// <summary>
/// 稠密轨迹离散限幅失败后允许统一拉长时间轴的最大次数。
/// </summary>
private const int MaxDenseLimitStretchIterations = 100;
/// <summary>
/// 每次离散限幅失败后统一放大的时间倍率。
/// </summary>
private const double DenseLimitStretchFactor = 1.01;
/// <summary>
/// 平滑起停重定时混合系数0 表示不平滑1 表示完全使用平滑时间律。
/// 当前取值用于“弱平滑”,仅轻微拉伸首尾时间段,避免起停过慢。
/// </summary>
private const double SmoothStartStopBlend = 0.60;
private readonly ICspPlanner _icspPlanner;
private readonly SelfAdaptIcspPlanner _selfAdaptIcspPlanner;
private readonly ShotTimelineBuilder _shotTimelineBuilder = new(new WaypointTimestampResolver());
private readonly Dictionary<string, PlannedExecutionBundle> _flyshotCache = new(StringComparer.Ordinal);
private readonly ILogger<ControllerClientTrajectoryOrchestrator>? _logger;
/// <summary>
/// 初始化轨迹编排器。
/// </summary>
/// <param name="logger">日志记录器;允许 null。</param>
/// <param name="loggerFactory">日志工厂;允许 null。</param>
public ControllerClientTrajectoryOrchestrator(
ILogger<ControllerClientTrajectoryOrchestrator>? logger = null,
ILoggerFactory? loggerFactory = null)
{
_logger = logger;
_icspPlanner = new(logger: loggerFactory?.CreateLogger<ICspPlanner>());
_selfAdaptIcspPlanner = new(logger: loggerFactory?.CreateLogger<SelfAdaptIcspPlanner>());
}
/// <summary>
/// 对普通轨迹执行 ICSP 规划。
/// </summary>
/// <param name="robot">当前机器人配置。</param>
/// <param name="waypoints">普通轨迹关节路点。</param>
/// <param name="options">执行参数。</param>
/// <param name="planningSpeedScale">规划速度倍率。</param>
/// <returns>包含规划轨迹、空触发时间轴和执行结果的结果包。</returns>
public PlannedExecutionBundle PlanOrdinaryTrajectory(
RobotProfile robot,
IReadOnlyList<IReadOnlyList<double>> waypoints,
TrajectoryExecutionOptions? options = null,
double planningSpeedScale = 1.0)
{
ArgumentNullException.ThrowIfNull(robot);
ArgumentNullException.ThrowIfNull(waypoints);
options ??= new TrajectoryExecutionOptions();
var planningRobot = ApplyPlanningSpeedScale(robot, planningSpeedScale);
_logger?.LogInformation(
"PlanOrdinaryTrajectory 开始: 路点数={WaypointCount}, method={Method}, planningSpeedScale={PlanningSpeedScale}",
waypoints.Count, options.Method, planningSpeedScale);
var program = CreateProgram(
name: "ordinary-trajectory",
waypoints: waypoints,
shotFlags: Enumerable.Repeat(false, waypoints.Count),
offsetValues: Enumerable.Repeat(0, waypoints.Count),
addressGroups: Enumerable.Range(0, waypoints.Count).Select(static _ => Array.Empty<int>()));
var method = ParseOrdinaryMethod(options.Method);
var request = new TrajectoryRequest(
robot: planningRobot,
program: program,
method: method,
saveTrajectoryArtifacts: options.SaveTrajectory);
var plannedTrajectory = PlanByMethod(request, method);
var executionTrajectory = plannedTrajectory;
var denseJointTrajectory = CreateLimitCompliantDenseTrajectory(ref executionTrajectory, shapeTrajectoryEdges: false);
var shotTimeline = new ShotTimeline(Array.Empty<ShotEvent>(), Array.Empty<TrajectoryDoEvent>());
var result = CreateResult(
executionTrajectory,
shotTimeline,
denseJointTrajectory,
usedCache: false,
triggerSampleIndexOffsetCycles: 0);
_logger?.LogInformation(
"PlanOrdinaryTrajectory 完成: 时长={Duration}s, 采样点数={SampleCount}",
result.Duration.TotalSeconds,
result.DenseJointTrajectory?.Count ?? 0);
return new PlannedExecutionBundle(plannedTrajectory, shotTimeline, result);
}
/// <summary>
/// 对已经上传的飞拍轨迹执行自适应 ICSP 规划并生成触发时间轴。
/// </summary>
/// <param name="robot">当前机器人配置。</param>
/// <param name="uploaded">兼容层保存的上传轨迹。</param>
/// <param name="options">执行参数。</param>
/// <param name="settings">兼容层机器人设置。</param>
/// <param name="planningSpeedScale">规划速度倍率。</param>
/// <returns>包含规划轨迹、触发时间轴和执行结果的结果包。</returns>
public PlannedExecutionBundle PlanUploadedFlyshot(
RobotProfile robot,
ControllerClientCompatUploadedTrajectory uploaded,
FlyshotExecutionOptions? options = null,
CompatibilityRobotSettings? settings = null,
double? planningSpeedScale = null)
{
ArgumentNullException.ThrowIfNull(robot);
ArgumentNullException.ThrowIfNull(uploaded);
options ??= new FlyshotExecutionOptions();
settings ??= CreateDefaultRobotSettings();
var effectivePlanningSpeedScale = planningSpeedScale ?? settings.PlanningSpeedScale;
var planningRobot = ApplyPlanningSpeedScale(robot, effectivePlanningSpeedScale);
_logger?.LogInformation(
"PlanUploadedFlyshot 开始: name={Name}, waypoints={WaypointCount}, method={Method}, useCache={UseCache}, planningSpeedScale={PlanningSpeedScale}, smoothStartStopTiming={SmoothStartStopTiming}",
uploaded.Name, uploaded.Waypoints.Count, options.Method, options.UseCache, effectivePlanningSpeedScale, settings.SmoothStartStopTiming);
var program = CreateProgram(
name: uploaded.Name,
waypoints: uploaded.Waypoints,
shotFlags: uploaded.ShotFlags,
offsetValues: uploaded.OffsetValues,
addressGroups: uploaded.AddressGroups);
var method = ParseFlyshotMethod(options.Method);
var cacheKey = CreateFlyshotCacheKey(planningRobot, uploaded, options, settings, effectivePlanningSpeedScale);
if (options.UseCache && _flyshotCache.TryGetValue(cacheKey, out var cachedBundle))
{
_logger?.LogInformation("PlanUploadedFlyshot 命中缓存: name={Name}, cacheKey={CacheKey}", uploaded.Name, cacheKey);
// 命中缓存时只替换 TrajectoryResult 的 usedCache 标志,规划轨迹和触发时间轴保持不可变复用。
return cachedBundle;
}
var request = new TrajectoryRequest(
robot: planningRobot,
program: program,
method: method,
moveToStart: options.MoveToStart,
saveTrajectoryArtifacts: options.SaveTrajectory,
useCache: options.UseCache);
var plannedTrajectory = PlanByMethod(request, method, settings);
var smoothedExecutionTrajectory = ApplyExecutionTiming(plannedTrajectory, settings);
var denseJointTrajectory = CreateLimitCompliantDenseTrajectory(ref smoothedExecutionTrajectory, shapeTrajectoryEdges: false);
var shotTimeline = _shotTimelineBuilder.Build(
smoothedExecutionTrajectory,
holdCycles: settings.IoKeepCycles,
samplePeriod: planningRobot.ServoPeriod,
useDo: settings.UseDo);
var result = CreateResult(
smoothedExecutionTrajectory,
shotTimeline,
denseJointTrajectory,
usedCache: false,
triggerSampleIndexOffsetCycles: settings.TriggerSampleIndexOffsetCycles);
var bundle = new PlannedExecutionBundle(plannedTrajectory, shotTimeline, result);
_logger?.LogInformation(
"PlanUploadedFlyshot 完成: name={Name}, 时长={Duration}s, 触发事件数={TriggerCount}, 采样点数={SampleCount}",
uploaded.Name, result.Duration.TotalSeconds, result.TriggerTimeline.Count, result.DenseJointTrajectory?.Count ?? 0);
if (options.UseCache)
{
_flyshotCache[cacheKey] = bundle;
}
return bundle;
}
/// <summary>
/// 按普通轨迹执行接口约束解析 method 参数。
/// </summary>
/// <param name="method">旧 SDK 传入的方法名。</param>
/// <returns>领域层规划方法。</returns>
private static PlanningMethod ParseOrdinaryMethod(string method)
{
var normalized = NormalizeMethod(method);
return normalized switch
{
"icsp" => PlanningMethod.Icsp,
"doubles" => PlanningMethod.Doubles,
_ => throw new ArgumentException($"Unsupported ExecuteTrajectory method: {method}", nameof(method))
};
}
/// <summary>
/// 按飞拍轨迹执行接口约束解析 method 参数。
/// </summary>
/// <param name="method">旧 SDK 传入的方法名。</param>
/// <returns>领域层规划方法。</returns>
private static PlanningMethod ParseFlyshotMethod(string method)
{
var normalized = NormalizeMethod(method);
return normalized switch
{
"icsp" => PlanningMethod.Icsp,
"self-adapt-icsp" => PlanningMethod.SelfAdaptIcsp,
"doubles" => PlanningMethod.Doubles,
_ => throw new ArgumentException($"Unsupported ExecuteFlyShotTraj method: {method}", nameof(method))
};
}
/// <summary>
/// 按领域枚举分派到当前已经落地的规划器。
/// </summary>
/// <param name="request">规划请求。</param>
/// <param name="method">规划方法。</param>
/// <returns>规划轨迹。</returns>
private PlannedTrajectory PlanByMethod(TrajectoryRequest request, PlanningMethod method, CompatibilityRobotSettings? settings = null)
{
return method switch
{
PlanningMethod.Icsp => _icspPlanner.Plan(request),
PlanningMethod.SelfAdaptIcsp => _selfAdaptIcspPlanner.Plan(request, settings?.AdaptIcspTryNum ?? 5),
PlanningMethod.Doubles => throw new NotSupportedException("doubles 轨迹规划尚未落地。"),
_ => throw new ArgumentOutOfRangeException(nameof(method), method, "未知轨迹规划方法。")
};
}
/// <summary>
/// 归一化旧 SDK 的 method 字符串。
/// </summary>
/// <param name="method">原始方法名。</param>
/// <returns>小写短横线方法名。</returns>
private static string NormalizeMethod(string method)
{
if (string.IsNullOrWhiteSpace(method))
{
return "icsp";
}
return method.Trim().ToLowerInvariant();
}
/// <summary>
/// 为已上传飞拍轨迹构造包含参数和轨迹内容的缓存键,避免同名覆盖后误用旧规划结果。
/// </summary>
/// <param name="robot">机器人配置。</param>
/// <param name="uploaded">上传轨迹。</param>
/// <param name="options">执行参数。</param>
/// <returns>缓存键。</returns>
private static string CreateFlyshotCacheKey(
RobotProfile robot,
ControllerClientCompatUploadedTrajectory uploaded,
FlyshotExecutionOptions options,
CompatibilityRobotSettings settings,
double planningSpeedScale)
{
var hash = new HashCode();
hash.Add(robot.Name, StringComparer.Ordinal);
hash.Add(planningSpeedScale);
hash.Add(uploaded.Name, StringComparer.Ordinal);
hash.Add(NormalizeMethod(options.Method), StringComparer.Ordinal);
hash.Add(options.MoveToStart);
hash.Add(options.SaveTrajectory);
hash.Add(settings.UseDo);
hash.Add(settings.IoKeepCycles);
hash.Add(settings.TriggerSampleIndexOffsetCycles);
hash.Add(settings.AdaptIcspTryNum);
hash.Add(settings.SmoothStartStopTiming);
foreach (var limit in robot.JointLimits)
{
hash.Add(limit.JointName, StringComparer.Ordinal);
hash.Add(limit.VelocityLimit);
hash.Add(limit.AccelerationLimit);
hash.Add(limit.JerkLimit);
}
foreach (var waypoint in uploaded.Waypoints)
{
foreach (var value in waypoint)
{
hash.Add(value);
}
}
foreach (var flag in uploaded.ShotFlags)
{
hash.Add(flag);
}
foreach (var offset in uploaded.OffsetValues)
{
hash.Add(offset);
}
foreach (var group in uploaded.AddressGroups)
{
foreach (var address in group)
{
hash.Add(address);
}
}
return hash.ToHashCode().ToString("X8");
}
/// <summary>
/// 构造编排器直接调用时的默认兼容配置,保持既有单元测试中的 DO 生成行为。
/// </summary>
/// <returns>默认机器人兼容配置。</returns>
private static CompatibilityRobotSettings CreateDefaultRobotSettings()
{
return new CompatibilityRobotSettings(
useDo: true,
ioAddresses: Array.Empty<int>(),
ioKeepCycles: 0,
triggerSampleIndexOffsetCycles: 7,
accLimitScale: 1.0,
jerkLimitScale: 1.0,
adaptIcspTryNum: 5);
}
/// <summary>
/// 按运行配置决定是否对规划结果做执行前时间轴重映射。
/// </summary>
/// <param name="plannedTrajectory">规划阶段得到的轨迹。</param>
/// <param name="settings">当前 RobotConfig.json 解析出的兼容设置。</param>
/// <returns>运行时真正用于采样和触发的轨迹。</returns>
private static PlannedTrajectory ApplyExecutionTiming(PlannedTrajectory plannedTrajectory, CompatibilityRobotSettings settings)
{
// legacy-fit 模式需要严格保留 waypoint.txt 反推出的节点时间,不能再二次改写时间轴。
return settings.SmoothStartStopTiming
? ApplySmoothStartStopTiming(plannedTrajectory)
: plannedTrajectory;
}
/// <summary>
/// 按规划全局速度倍率生成规划专用机器人约束。
/// </summary>
/// <param name="robot">原始机器人约束。</param>
/// <param name="planningSpeedScale">规划阶段的全局速度倍率1.0 表示不额外缩放。</param>
/// <returns>已按速度倍率缩放后的规划机器人约束。</returns>
private static RobotProfile ApplyPlanningSpeedScale(RobotProfile robot, double planningSpeedScale)
{
if (double.IsNaN(planningSpeedScale) || double.IsInfinity(planningSpeedScale) || planningSpeedScale <= 0.0)
{
throw new ArgumentOutOfRangeException(nameof(planningSpeedScale), "规划速度倍率必须是有限正数。");
}
if (Math.Abs(planningSpeedScale - 1.0) < 1e-12)
{
return robot;
}
// RVBUST 规划阶段会用独立限速倍率缩放有效限制;运行时 speedRatio 仍只负责 J519 下发重采样。
var scaledLimits = robot.JointLimits
.Select(limit => new JointLimit(
limit.JointName,
limit.VelocityLimit * planningSpeedScale,
limit.AccelerationLimit * planningSpeedScale * planningSpeedScale,
limit.JerkLimit * planningSpeedScale * planningSpeedScale * planningSpeedScale))
.ToArray();
return new RobotProfile(
name: robot.Name,
modelPath: robot.ModelPath,
degreesOfFreedom: robot.DegreesOfFreedom,
jointLimits: scaledLimits,
jointCouplings: robot.JointCouplings,
servoPeriod: robot.ServoPeriod,
triggerPeriod: robot.TriggerPeriod);
}
/// <summary>
/// 把兼容层输入数组转换成领域层 FlyshotProgram。
/// </summary>
/// <param name="name">轨迹名称。</param>
/// <param name="waypoints">关节路点。</param>
/// <param name="shotFlags">拍照标志。</param>
/// <param name="offsetValues">偏移周期。</param>
/// <param name="addressGroups">IO 地址组。</param>
/// <returns>领域层飞拍程序。</returns>
private static FlyshotProgram CreateProgram(
string name,
IEnumerable<IReadOnlyList<double>> waypoints,
IEnumerable<bool> shotFlags,
IEnumerable<int> offsetValues,
IEnumerable<IReadOnlyList<int>> addressGroups)
{
return new FlyshotProgram(
name: name,
waypoints: waypoints.Select(static waypoint => new JointWaypoint(waypoint)).ToArray(),
shotFlags: shotFlags.ToArray(),
offsetValues: offsetValues.ToArray(),
addressGroups: addressGroups.Select(static group => new IoAddressGroup(group)).ToArray());
}
/// <summary>
/// 从规划轨迹和触发时间轴构造运行时可消费的稳定结果对象。
/// </summary>
/// <param name="plannedTrajectory">规划后的轨迹。</param>
/// <param name="shotTimeline">触发时间轴。</param>
/// <returns>运行时执行结果描述。</returns>
private static TrajectoryResult CreateResult(
PlannedTrajectory plannedTrajectory,
ShotTimeline shotTimeline,
IReadOnlyList<IReadOnlyList<double>> denseJointTrajectory,
bool usedCache,
int triggerSampleIndexOffsetCycles)
{
return new TrajectoryResult(
programName: plannedTrajectory.OriginalProgram.Name,
method: plannedTrajectory.Method,
isValid: true,
duration: TimeSpan.FromSeconds(plannedTrajectory.WaypointTimes[^1]),
shotEvents: shotTimeline.ShotEvents,
triggerTimeline: shotTimeline.TriggerTimeline,
artifacts: Array.Empty<TrajectoryArtifact>(),
failureReason: null,
usedCache: usedCache,
originalWaypointCount: plannedTrajectory.OriginalWaypointCount,
plannedWaypointCount: plannedTrajectory.PlannedWaypointCount,
triggerSampleIndexOffsetCycles: triggerSampleIndexOffsetCycles,
denseJointTrajectory: denseJointTrajectory);
}
/// <summary>
/// 生成满足离散速度、加速度和 Jerk 限制的稠密执行轨迹。
/// </summary>
private IReadOnlyList<IReadOnlyList<double>> CreateLimitCompliantDenseTrajectory(
ref PlannedTrajectory executionTrajectory,
bool shapeTrajectoryEdges)
{
for (var iteration = 0; iteration <= MaxDenseLimitStretchIterations; iteration++)
{
var denseJointTrajectory = TrajectorySampler.SampleJointTrajectory(
executionTrajectory,
samplePeriod: executionTrajectory.Robot.ServoPeriod.TotalSeconds,
smoothStartStop: shapeTrajectoryEdges);
try
{
TrajectoryLimitValidator.ValidateDenseJointTrajectory(
executionTrajectory.Robot,
denseJointTrajectory,
trajectoryName: executionTrajectory.OriginalProgram.Name);
return denseJointTrajectory;
}
catch (InvalidOperationException ex) when (iteration < MaxDenseLimitStretchIterations)
{
_logger?.LogWarning(ex, "稠密轨迹离散限幅校验失败,准备拉长时间轴重试");
// 离散差分超限时统一拉长时间轴,保持路点几何不变并降低速度、加速度和 Jerk。
executionTrajectory = StretchTrajectoryTiming(executionTrajectory, DenseLimitStretchFactor);
_logger?.LogInformation(
"离散差分超限拉长时间轴iteration={Iteration}, factor={StretchFactor}",
iteration,
DenseLimitStretchFactor);
_logger?.LogInformation("拉长之后的总时间={TotalTime}", executionTrajectory.WaypointTimes[^1]);
}
}
throw new InvalidOperationException("稠密轨迹离散限幅校验未能产生有效结果。");
}
/// <summary>
/// 按统一倍率拉长轨迹时间轴,保留原始路点和触发元数据。
/// </summary>
private PlannedTrajectory StretchTrajectoryTiming(PlannedTrajectory trajectory, double stretchFactor)
{
var waypointTimes = trajectory.WaypointTimes.Select(time => time * stretchFactor).ToArray();
var segmentDurations = trajectory.SegmentDurations.Select(duration => duration * stretchFactor).ToArray();
var segmentScales = trajectory.SegmentScales.Select(scale => scale / stretchFactor).ToArray();
return new PlannedTrajectory(
robot: trajectory.Robot,
originalProgram: trajectory.OriginalProgram,
plannedWaypoints: trajectory.PlannedWaypoints,
waypointTimes: waypointTimes,
segmentDurations: segmentDurations,
segmentScales: segmentScales,
method: trajectory.Method,
iterations: trajectory.Iterations,
threshold: trajectory.Threshold);
}
/// <summary>
/// 为飞拍执行生成平滑起停时间轴(仅重定时,不改几何路点)。
/// 该方法保持 <see cref="PlannedTrajectory.PlannedWaypoints"/> 不变,只重映射 <see cref="PlannedTrajectory.WaypointTimes"/>
/// 让轨迹在起点和终点附近具有更柔和的速度变化,从而降低“突然起步/突然收尾”带来的离散差分尖峰。
/// </summary>
/// <param name="plannedTrajectory">规划器输出的原始轨迹(通常是线性时间轴)。</param>
/// <returns>
/// 若满足平滑条件,则返回新的重定时轨迹;若路点数量不足或总时长无效,则直接返回输入轨迹。
/// </returns>
private static PlannedTrajectory ApplySmoothStartStopTiming(PlannedTrajectory plannedTrajectory)
{
var originalTimes = plannedTrajectory.WaypointTimes;
// 至少需要“起点-中间点-终点”三类点,才有可平滑的中间区间。
if (originalTimes.Count < 3)
{
return plannedTrajectory;
}
var totalDuration = originalTimes[^1];
// 轨迹总时长必须为正,避免后续归一化进度出现除零或无意义映射。
if (totalDuration <= 0.0)
{
return plannedTrajectory;
}
var smoothedTimes = new double[originalTimes.Count];
// 强制固定边界:起点仍在 0终点仍在总时长保证任务总耗时不变。
smoothedTimes[0] = 0.0;
smoothedTimes[^1] = totalDuration;
for (var index = 1; index < originalTimes.Count - 1; index++)
{
// 把原始时刻归一化到 [0, 1],用于统一时间律变换。
var normalizedProgress = originalTimes[index] / totalDuration;
// 先求完整平滑时间律对应的时刻,再与原线性时刻按比例混合。
// 这里采用弱平滑blend=0.35):保留大部分原节奏,仅轻微降低首尾突变。
var smoothedProgress = InvertSmoothStartStopProgress(normalizedProgress);
var blendedProgress = ((1.0 - SmoothStartStopBlend) * normalizedProgress)
+ (SmoothStartStopBlend * smoothedProgress);
smoothedTimes[index] = totalDuration * blendedProgress;
}
var segmentDurations = new double[smoothedTimes.Length - 1];
for (var index = 0; index < segmentDurations.Length; index++)
{
// 重建每段持续时间,供后续稠密采样和限幅检查使用。
segmentDurations[index] = smoothedTimes[index + 1] - smoothedTimes[index];
}
return new PlannedTrajectory(
robot: plannedTrajectory.Robot,
originalProgram: plannedTrajectory.OriginalProgram,
plannedWaypoints: plannedTrajectory.PlannedWaypoints,
waypointTimes: smoothedTimes,
segmentDurations: segmentDurations,
segmentScales: plannedTrajectory.SegmentScales,
method: plannedTrajectory.Method,
iterations: plannedTrajectory.Iterations,
threshold: plannedTrajectory.Threshold);
}
/// <summary>
/// 反解平滑时间律进度:给定目标进度 p求满足 f(t)=p 的 t。
/// 其中 f(t) 由 <see cref="EvaluateSmoothStartStopProgress"/> 给出,是单调递增的 7 次 smootherstep 曲线,
/// 通过二分法可稳定得到对应的归一化时间,避免显式求高次方程根带来的复杂性和数值不稳定。
/// </summary>
/// <param name="normalizedProgress">目标归一化进度,理论范围 [0, 1]。</param>
/// <returns>与目标进度对应的归一化时间,范围 [0, 1]。</returns>
private static double InvertSmoothStartStopProgress(double normalizedProgress)
{
// 防御式裁剪,避免上游浮点误差将进度推到区间外。
var target = Math.Clamp(normalizedProgress, 0.0, 1.0);
var low = 0.0;
var high = 1.0;
// 固定迭代次数确保耗时可预测40 次足以把区间收敛到工程可用精度。
for (var iteration = 0; iteration < 40; iteration++)
{
var middle = (low + high) / 2.0;
var progress = EvaluateSmoothStartStopProgress(middle);
// f(middle) 小于目标,说明根在右半区间;否则在左半区间。
if (progress < target)
{
low = middle;
}
else
{
high = middle;
}
}
return (low + high) / 2.0;
}
/// <summary>
/// 计算 7 次 smootherstep 的进度函数值 f(u)。
/// 该函数在 u=0 和 u=1 处具有更高阶导数连续性,可让起停段速度变化更平滑,
/// 适合用于飞拍轨迹的时间重参数化,减少离散导数在边界处的突变。
/// </summary>
/// <param name="normalizedTime">归一化时间 u理论范围 [0, 1]。</param>
/// <returns>归一化进度 f(u),范围 [0, 1]。</returns>
private static double EvaluateSmoothStartStopProgress(double normalizedTime)
{
// 先裁剪再计算多项式,确保数值稳定且不受外部越界输入影响。
var u = Math.Clamp(normalizedTime, 0.0, 1.0);
var u2 = u * u;
var u3 = u2 * u;
var u4 = u3 * u;
var u5 = u4 * u;
var u6 = u5 * u;
var u7 = u6 * u;
return (35.0 * u4) - (84.0 * u5) + (70.0 * u6) - (20.0 * u7);
}
}