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diff --git a/extern/draco/draco/src/draco/compression/attributes/prediction_schemes/prediction_scheme_normal_octahedron_encoding_transform.h b/extern/draco/draco/src/draco/compression/attributes/prediction_schemes/prediction_scheme_normal_octahedron_encoding_transform.h
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+++ b/extern/draco/draco/src/draco/compression/attributes/prediction_schemes/prediction_scheme_normal_octahedron_encoding_transform.h
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+// Copyright 2016 The Draco Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#ifndef DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_PREDICTION_SCHEME_NORMAL_OCTAHEDRON_ENCODING_TRANSFORM_H_
+#define DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_PREDICTION_SCHEME_NORMAL_OCTAHEDRON_ENCODING_TRANSFORM_H_
+
+#include <cmath>
+
+#include "draco/compression/attributes/normal_compression_utils.h"
+#include "draco/compression/attributes/prediction_schemes/prediction_scheme_normal_octahedron_transform_base.h"
+#include "draco/core/encoder_buffer.h"
+#include "draco/core/macros.h"
+#include "draco/core/vector_d.h"
+
+namespace draco {
+
+// The transform works on octahedral coordinates for normals. The square is
+// subdivided into four inner triangles (diamond) and four outer triangles. The
+// inner triangles are associated with the upper part of the octahedron and the
+// outer triangles are associated with the lower part.
+// Given a prediction value P and the actual value Q that should be encoded,
+// this transform first checks if P is outside the diamond. If so, the outer
+// triangles are flipped towards the inside and vice versa. The actual
+// correction value is then based on the mapped P and Q values. This tends to
+// result in shorter correction vectors.
+// This is possible since the P value is also known by the decoder, see also
+// ComputeCorrection and ComputeOriginalValue functions.
+// Note that the tile is not periodic, which implies that the outer edges can
+// not be identified, which requires us to use an odd number of values on each
+// axis.
+// DataTypeT is expected to be some integral type.
+//
+template <typename DataTypeT>
+class PredictionSchemeNormalOctahedronEncodingTransform
+    : public PredictionSchemeNormalOctahedronTransformBase<DataTypeT> {
+ public:
+  typedef PredictionSchemeNormalOctahedronTransformBase<DataTypeT> Base;
+  typedef VectorD<DataTypeT, 2> Point2;
+  typedef DataTypeT CorrType;
+  typedef DataTypeT DataType;
+
+  // We expect the mod value to be of the form 2^b-1.
+  explicit PredictionSchemeNormalOctahedronEncodingTransform(
+      DataType max_quantized_value)
+      : Base(max_quantized_value) {}
+
+  void Init(const DataTypeT *orig_data, int size, int num_components) {}
+
+  bool EncodeTransformData(EncoderBuffer *buffer) {
+    buffer->Encode(this->max_quantized_value());
+    return true;
+  }
+
+  inline void ComputeCorrection(const DataType *orig_vals,
+                                const DataType *pred_vals,
+                                CorrType *out_corr_vals) const {
+    DRACO_DCHECK_LE(pred_vals[0], this->center_value() * 2);
+    DRACO_DCHECK_LE(pred_vals[1], this->center_value() * 2);
+    DRACO_DCHECK_LE(orig_vals[0], this->center_value() * 2);
+    DRACO_DCHECK_LE(orig_vals[1], this->center_value() * 2);
+    DRACO_DCHECK_LE(0, pred_vals[0]);
+    DRACO_DCHECK_LE(0, pred_vals[1]);
+    DRACO_DCHECK_LE(0, orig_vals[0]);
+    DRACO_DCHECK_LE(0, orig_vals[1]);
+
+    const Point2 orig = Point2(orig_vals[0], orig_vals[1]);
+    const Point2 pred = Point2(pred_vals[0], pred_vals[1]);
+    const Point2 corr = ComputeCorrection(orig, pred);
+
+    out_corr_vals[0] = corr[0];
+    out_corr_vals[1] = corr[1];
+  }
+
+ private:
+  Point2 ComputeCorrection(Point2 orig, Point2 pred) const {
+    const Point2 t(this->center_value(), this->center_value());
+    orig = orig - t;
+    pred = pred - t;
+
+    if (!this->IsInDiamond(pred[0], pred[1])) {
+      this->InvertDiamond(&orig[0], &orig[1]);
+      this->InvertDiamond(&pred[0], &pred[1]);
+    }
+
+    Point2 corr = orig - pred;
+    corr[0] = this->MakePositive(corr[0]);
+    corr[1] = this->MakePositive(corr[1]);
+    return corr;
+  }
+};
+
+}  // namespace draco
+
+#endif  // DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_PREDICTION_SCHEME_NORMAL_OCTAHEDRON_ENCODING_TRANSFORM_H_