Head-tracking library for Immersive Audio
See README.md for details.
Bug: 188502620
Test: atest --host libheadtracking-test
Change-Id: I34201c4780e5e581cc96449bd89863bcbc250783
diff --git a/media/libheadtracking/PoseDriftCompensator.cpp b/media/libheadtracking/PoseDriftCompensator.cpp
new file mode 100644
index 0000000..9dfe172
--- /dev/null
+++ b/media/libheadtracking/PoseDriftCompensator.cpp
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * 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 "PoseDriftCompensator.h"
+
+#include <cmath>
+
+#include "QuaternionUtil.h"
+
+namespace android {
+namespace media {
+
+using Eigen::Quaternionf;
+using Eigen::Vector3f;
+
+PoseDriftCompensator::PoseDriftCompensator(const Options& options) : mOptions(options) {}
+
+void PoseDriftCompensator::setInput(int64_t timestamp, const Pose3f& input) {
+ if (!mTimestamp.has_value()) {
+ // First input sample sets the output directly.
+ mOutput = input;
+ } else {
+ Pose3f prevInputToInput = mPrevInput.inverse() * input;
+ mOutput = scale(mOutput, timestamp - mTimestamp.value()) * prevInputToInput;
+ }
+ mPrevInput = input;
+ mTimestamp = timestamp;
+}
+
+void PoseDriftCompensator::recenter() {
+ mOutput = Pose3f();
+}
+
+Pose3f PoseDriftCompensator::getOutput() const {
+ return mOutput;
+}
+
+Pose3f PoseDriftCompensator::scale(const Pose3f& pose, int64_t dt) {
+ // Translation.
+ Vector3f translation = pose.translation();
+ translation *= std::expf(-static_cast<float>(dt) / mOptions.translationalDriftTimeConstant);
+
+ // Rotation.
+ Vector3f rotationVec = quaternionToRotationVector(pose.rotation());
+ rotationVec *= std::expf(-static_cast<float>(dt) / mOptions.rotationalDriftTimeConstant);
+
+ return Pose3f(translation, rotationVectorToQuaternion(rotationVec));
+}
+
+} // namespace media
+} // namespace android