GFBANM.cs

            public STKeyFrame GetFVGFL(STAnimationTrack t, float frame, float startFrame = 0)
            {
                if (t.KeyFrames.Count == 0) return new STKeyFrame(frame, 0);
                if (t.KeyFrames.Count == 1) return t.KeyFrames[0];

                STKeyFrame LK = t.KeyFrames.First();

                float Frame = frame - startFrame;

                foreach (STKeyFrame keyFrame in t.KeyFrames)
                {
                    if (keyFrame.Frame <= Frame) LK = keyFrame;
                }

                return LK;
            }

            public STKeyFrame GetFVGFR(STAnimationTrack t, float frame, float startFrame = 0)
            {
                if (t.KeyFrames.Count == 0) return new STKeyFrame(frame, 0);
                if (t.KeyFrames.Count == 1) return t.KeyFrames[0];

                STKeyFrame RK = t.KeyFrames.Last();

                float Frame = frame - startFrame;

                foreach (STKeyFrame keyFrame in t.KeyFrames)
                {
                    if (keyFrame.Frame >= Frame && keyFrame.Frame < RK.Frame) RK = keyFrame;
                }

                return RK;
            }

            // private static readonly ushort _flagsMask = 0b11000011_11111111;

            private static short UnpackS15(short u15)
            {
                int sign = (u15 >> 14) & 1;
                u15 &= 0x3FFF;
                if (sign == 0) u15 -= 0x4000;
                return u15;
            }

            static int[][] QUATERNION_SWIZZLES =  {
                  new int[] { 0, 3, 2, 1 }, new int[] { 3, 0, 2, 1 },
                  new int[] { 3, 2, 0, 1 }, new int[] { 3, 2, 1, 0 }
            };

            private static Quaternion PackedToQuat(short z, short y, short x)
            {

                const int count = 15;
                const int BASE = (1 << count) - 1;
                float maxval = 1 / (0x399E * (float)Math.Sqrt(2.0)); // such obvious, so constant, wow

                long cq = x & 0xFFFF;
                cq <<= 16;
                cq |= ((uint)y) & 0xFFFF;
                cq <<= 16;
                cq |= ((uint)z) & 0xFFFF;


                short extra = (short)(cq & 0x7);

                long num = cq >> 3;

                x = UnpackS15((short)((num >> (count * 2)) & BASE));
                y = UnpackS15((short)((num >> (count * 1)) & BASE));
                z = UnpackS15((short)((num >> (count * 0)) & BASE));

                float fx = x * maxval;
                float fy = y * maxval;
                float fz = z * maxval;

                float[] quat = {
                    (float)Math.Sqrt(1 - fx * fx - fy * fy - fz * fz),
                    fx,
                    fy,
                    fz };

                int[] qmap = QUATERNION_SWIZZLES[(extra & 3)];
                Quaternion q = new Quaternion(quat[qmap[0]], quat[qmap[1]], quat[qmap[2]], quat[qmap[3]]);
                if ((extra >> 2) != 0) q *= -1;

                return q;

            }

            public static Quaternion EulerToQuat(float z, float y, float x)
            {
                Quaternion xRotation = Quaternion.FromAxisAngle(Vector3.UnitX, x);
                Quaternion yRotation = Quaternion.FromAxisAngle(Vector3.UnitY, y);
                Quaternion zRotation = Quaternion.FromAxisAngle(Vector3.UnitZ, z);
                return (zRotation * yRotation * xRotation);
            }