private void SetOnSteeringWheel(Matrix steerMatrix, float swRadius)
{
// point on the wheel, matrix
var l = Matrix.Translation(swRadius * _side, 0, 0) * steerMatrix;
var lPos = l.GetTranslationVector();
// vertical offset of point on the wheel after rotation
var armUp = Vector3.TransformNormal(Vector3.UnitX, steerMatrix);
// approximate direction
var approxDirection = lPos - _approxPoint;
// move hand
var handUp = Vector3.Normalize(Vector3.TransformNormal(Vector3.UnitX * 6f + Vector3.UnitY * _side, l));
var handXFix = Vector3.Normalize(new Vector3(approxDirection.X, Math.Min(approxDirection.Y, 0f) * 5f, approxDirection.Z.Abs() + 0.2f)).X;
handXFix = ((handXFix.Abs() - 0.1f) * 6f).Saturate() * handXFix.Sign() * 5f;
var handLookAt = Vector3.TransformCoordinate(Vector3.UnitZ * 5f, steerMatrix) + // really far into the wheel
Vector3.UnitY * (4f + armUp.Y * 2f) * (armUp.X * 2f).Saturate() + // sort of upwards depending on how high it’s on the wheel
Vector3.UnitX * handXFix; // on the side to avoid breaking
_hand.LookAt(handLookAt, handUp);
var downK = (_side * -armUp.Y / 0.5f - 0.5f).Saturate();
_indexf.Set(0.8f - downK * 0.3f);
_middle.Set(0.9f - downK * 0.8f);
_ring.Set(1f - downK);
_pinkie.Set(1f - downK);
if (_side > 0f)
{
_ds = $"v: {armUp}\r\nn: {handUp}\r\nx fix: {handXFix}\r\na.p.: {_approxPoint}\r\nl.p.: {lPos}\r\na.d.: {approxDirection}";
}
// after moved, update target point
var targetPoint = _hand.Matrix.GetTranslationVector() + GetThumbsOffset(steerMatrix, swRadius);
MoveHand(targetPoint, armUp, handUp);
// move hand, again
_hand.LookAt(handLookAt, handUp);
}
private void MoveHand(Vector3 targetPoint, Vector3 up, Vector3 handUp)
{
_targetPoint = targetPoint;
_up = up;
_handUp = handUp;
// static stuff
var handLength = _armLength + _forearmLength + _forearmEndLength;
// approximate direction
var approxDirection = targetPoint - _approxPoint;
// move shoulder
var approxDistance = approxDirection.Length();
var shoulderFix = Smooth(Math.Max(approxDistance - handLength + 0.1f, 0f) / 0.2f);
_clave.LocalMatrix =
Matrix.RotationYawPitchRoll(_side * 17f.ToRadians(), (-12f - 40f * shoulderFix).ToRadians(), (_side > 0 ? -95f : 95f).ToRadians()) *
Matrix.Translation(0.02f * _side, 0.11f + 0.08f * shoulderFix, 0.05f + 0.05f * shoulderFix);
var armPoint = _arm.Matrix.GetTranslationVector();
var armDelta = targetPoint - armPoint;
// comparing distance to point with hand length
var distance = armDelta.Length();
var relative = distance / handLength;
if (relative > _smoothFrom)
{
var leftMax = 1f - _smoothFrom;
var left = relative - _smoothFrom;
var smooth = left / leftMax;
var smoother = -0.5f + MathF.Sqrt(1f + 3f * smooth) / 2f;
distance = handLength * (_smoothFrom + smoother * leftMax);
}
/*if (distance > handLength * _smoothFrom && distance < handLength * _smoothStretch) {
* var left = handLength - distance;
* var leftK = (left / (1f - _smoothFrom)).Saturate();
*
* // leftK = 0 → handLength * _smoothFrom
* // leftK + very small x → handLength * _smoothFrom + very small x
* // leftK = _smoothFrom - 1 → handLength * _smoothStretch
*
* // var stretchTo = _smoothStretch;
* distance = handLength * _smoothFrom + leftK * (_smoothStretch - _smoothFrom) * handLength;
* }*/
var overOffset = MathF.Sqrt(Math.Max(MathF.Pow(handLength, 2f) - MathF.Pow(distance, 2f), 0f));
// normals: direction, bottom normal for elbow offset
var direction = Vector3.Normalize(armDelta);
var verticalOffsetFixed = up;
verticalOffsetFixed.Y = _side * verticalOffsetFixed.Y.Abs();
verticalOffsetFixed.Z += _side;
var armBottom = Vector3.Normalize(Vector3.Cross(direction, -Vector3.Normalize(verticalOffsetFixed)));
// moving shoulder
var armUp = (-armBottom + Vector3.UnitY * 2f) / 3f * _side;
var armLookAt = armPoint + Vector3.Normalize(targetPoint - armPoint) * _armLength +
armBottom * overOffset * _armLength / handLength;
_arm.LookAt(armLookAt, armUp);
_forearm.LookAt(targetPoint, Vector3.UnitY * _side);
_forearmEnd.LookAt(targetPoint, handUp);
}