SA.FullBodyIK._LimitFingerNotThumb C# (CSharp) Method

		public static bool _LimitFingerNotThumb(
			bool isRight,
			ref Vector3 dir, // dirX
			ref FastAngle limitYPlus,
			ref FastAngle limitYMinus,
			ref FastAngle limitZ )
		{
			bool isLimited = false;

			// Yaw
			if( limitZ.cos > IKEpsilon ) {
				// Memo: Unstable when dir.z near 1.
				if( dir.z < -limitZ.sin || dir.z > limitZ.sin ) {
					isLimited = true;
					bool isPlus = (dir.z >= 0.0f);
					float lenXY = SAFBIKSqrt( dir.x * dir.x + dir.y * dir.y );
					if( limitZ.sin <= IKEpsilon ) { // Optimized.
						if( lenXY > IKEpsilon ) {
							dir.z = 0.0f;
							dir = dir * (1.0f / lenXY);
						} else { // Failsafe.
							dir.Set( isRight ? limitZ.cos : -limitZ.cos, 0.0f, isPlus ? limitZ.sin : -limitZ.sin );
						}
					} else {
						float lenZ = limitZ.sin * lenXY / limitZ.cos;
						dir.z = isPlus ? lenZ : -lenZ;

						float len = dir.magnitude;
						if( len > IKEpsilon ) {
							dir *= (1.0f / len);
						} else { // Failsafe.
							dir.Set( isRight ? limitZ.cos : -limitZ.cos, 0.0f, isPlus ? limitZ.sin : -limitZ.sin );
						}
					}
				}
			}

			// Pitch
			{
				// Memo: Not use z.( For yaw limit. )
				bool isPlus = (dir.y >= 0.0f);
				float cosPitchLimit = isPlus ? limitYPlus.cos : limitYMinus.cos;
				if( (isRight && dir.x < cosPitchLimit) || (!isRight && dir.x > -cosPitchLimit) ) {
					float lenY = SAFBIKSqrt( 1.0f - (cosPitchLimit * cosPitchLimit + dir.z * dir.z) );
					dir.x = (isRight ? cosPitchLimit : -cosPitchLimit);
					dir.y = (isPlus ? lenY : -lenY);
				}
			}

			return isLimited;
		}
	}