diff --git a/media/libheadtracking/ScreenHeadFusion.cpp b/media/libheadtracking/ScreenHeadFusion.cpp
new file mode 100644
index 0000000..f023570
--- /dev/null
+++ b/media/libheadtracking/ScreenHeadFusion.cpp
@@ -0,0 +1,41 @@
+/*
+ * 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 "ScreenHeadFusion.h"
+
+namespace android {
+namespace media {
+
+void ScreenHeadFusion::setWorldToHeadPose(int64_t timestamp, const Pose3f& worldToHead) {
+    mWorldToHead = TimestampedPose{.timestamp = timestamp, .pose = worldToHead};
+}
+
+void ScreenHeadFusion::setWorldToScreenPose(int64_t timestamp, const Pose3f& worldToScreen) {
+    mWorldToScreen = TimestampedPose{.timestamp = timestamp, .pose = worldToScreen};
+}
+
+std::optional<ScreenHeadFusion::TimestampedPose> ScreenHeadFusion::calculate() {
+    // TODO: this is temporary, simplistic logic.
+    if (!mWorldToHead.has_value() || !mWorldToScreen.has_value()) {
+        return std::nullopt;
+    }
+    return TimestampedPose{
+            .timestamp = std::min(mWorldToHead->timestamp, mWorldToScreen->timestamp),
+            .pose = mWorldToScreen->pose.inverse() * mWorldToHead->pose};
+}
+
+}  // namespace media
+}  // namespace android