1 files changed, 94 insertions, 0 deletions
diff --git a/src/3rdparty/resonance-audio/resonance_audio/base/misc_math.cc b/src/3rdparty/resonance-audio/resonance_audio/base/misc_math.cc
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index 000000000..4de96ba41
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+++ b/src/3rdparty/resonance-audio/resonance_audio/base/misc_math.cc
@@ -0,0 +1,94 @@
+/*
+Copyright 2018 Google Inc. All Rights Reserved.
+
+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.
+*/
+
+#include "base/misc_math.h"
+
+namespace vraudio {
+
+WorldPosition::WorldPosition() { setZero(); }
+
+WorldRotation::WorldRotation() { setIdentity(); }
+
+bool LinearLeastSquareFitting(const std::vector<float>& x_array,
+                              const std::vector<float>& y_array, float* slope,
+                              float* intercept, float* r_squared) {
+  // The array sizes must agree.
+  if (x_array.size() != y_array.size()) {
+    return false;
+  }
+
+  // At least two points are needed to fit a line.
+  if (x_array.size() < 2) {
+    return false;
+  }
+
+  float x_sum = 0.0f;
+  float y_sum = 0.0f;
+  float x_square_sum = 0.0f;
+  float xy_sum = 0.0f;
+
+  for (size_t i = 0; i < x_array.size(); ++i) {
+    const float x = x_array[i];
+    const float y = y_array[i];
+    x_sum += x;
+    y_sum += y;
+    x_square_sum += x * x;
+    xy_sum += x * y;
+  }
+
+  const float n_inverse = 1.0f / static_cast<float>(x_array.size());
+  const float x_mean = x_sum * n_inverse;
+  const float y_mean = y_sum * n_inverse;
+  const float x_square_mean = x_square_sum * n_inverse;
+  const float xy_mean = xy_sum * n_inverse;
+  const float x_mean_square = x_mean * x_mean;
+
+  // Prevent division by zero, which means a vertical line and the slope is
+  // infinite.
+  if (x_square_mean == x_mean_square) {
+    return false;
+  }
+
+  *slope = (xy_mean - x_mean * y_mean) / (x_square_mean - x_mean_square);
+  *intercept = y_mean - *slope * x_mean;
+
+  // Compute the coefficient of determination.
+  float total_sum_of_squares = 0.0f;
+  float residual_sum_of_squares = 0.0f;
+  for (size_t i = 0; i < x_array.size(); ++i) {
+    const float y_i = y_array[i];
+    total_sum_of_squares += (y_i - y_mean) * (y_i - y_mean);
+    const float y_fit = *slope * x_array[i] + *intercept;
+    residual_sum_of_squares += (y_fit - y_i) * (y_fit - y_i);
+  }
+
+  if (total_sum_of_squares == 0.0f) {
+    if (residual_sum_of_squares == 0.0f) {
+      // A special case where all y's are equal, where the |r_squared| should
+      // be 1.0, and the line is a perfectly horizontal line.
+      *r_squared = 1.0f;
+      return true;
+    } else {
+      // Division by zero.
+      return false;
+    }
+  }
+
+  *r_squared = 1.0f - residual_sum_of_squares / total_sum_of_squares;
+  return true;
+}
+
+}  // namespace vraudio