61 lines
2.5 KiB
C#
61 lines
2.5 KiB
C#
using UnityEngine.Scripting.APIUpdating;
|
|
|
|
namespace UnityEngine.U2D.IK
|
|
{
|
|
/// <summary>
|
|
/// Utility for 2D based Cyclic Coordinate Descent (CCD) IK Solver.
|
|
/// </summary>
|
|
[MovedFrom("UnityEngine.Experimental.U2D.IK")]
|
|
public static class CCD2D
|
|
{
|
|
/// <summary>
|
|
/// Solve IK Chain based on CCD.
|
|
/// </summary>
|
|
/// <param name="targetPosition">Target position.</param>
|
|
/// <param name="forward">Forward vector for solver.</param>
|
|
/// <param name="solverLimit">Solver iteration count.</param>
|
|
/// <param name="tolerance">Target position's tolerance.</param>
|
|
/// <param name="velocity">Velocity towards target position.</param>
|
|
/// <param name="positions">Chain positions.</param>
|
|
/// <returns>Returns true if solver successfully completes within iteration limit. False otherwise.</returns>
|
|
public static bool Solve(Vector3 targetPosition, Vector3 forward, int solverLimit, float tolerance, float velocity, ref Vector3[] positions)
|
|
{
|
|
var last = positions.Length - 1;
|
|
var iterations = 0;
|
|
var sqrTolerance = tolerance * tolerance;
|
|
var sqrDistanceToTarget = (targetPosition - positions[last]).sqrMagnitude;
|
|
while (sqrDistanceToTarget > sqrTolerance)
|
|
{
|
|
DoIteration(targetPosition, forward, last, velocity, ref positions);
|
|
sqrDistanceToTarget = (targetPosition - positions[last]).sqrMagnitude;
|
|
if (++iterations >= solverLimit)
|
|
break;
|
|
}
|
|
|
|
return iterations != 0;
|
|
}
|
|
|
|
static void DoIteration(Vector3 targetPosition, Vector3 forward, int last, float velocity, ref Vector3[] positions)
|
|
{
|
|
for (var i = last - 1; i >= 0; --i)
|
|
{
|
|
var toTarget = targetPosition - positions[i];
|
|
var toLast = positions[last] - positions[i];
|
|
|
|
var angle = Vector3.SignedAngle(toLast, toTarget, forward);
|
|
angle = Mathf.Lerp(0f, angle, velocity);
|
|
|
|
var deltaRotation = Quaternion.AngleAxis(angle, forward);
|
|
for (var j = last; j > i; --j)
|
|
positions[j] = RotatePositionFrom(positions[j], positions[i], deltaRotation);
|
|
}
|
|
}
|
|
|
|
static Vector3 RotatePositionFrom(Vector3 position, Vector3 pivot, Quaternion rotation)
|
|
{
|
|
var v = position - pivot;
|
|
v = rotation * v;
|
|
return pivot + v;
|
|
}
|
|
}
|
|
} |