1 /*
2  * Copyright (C) 2022 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 #pragma once
17 
18 #include "media/Pose.h"
19 
20 namespace android {
21 namespace media {
22 
23 /**
24  * Biasing for a stream of poses.
25  *
26  * This filter takes a stream of poses and at any time during the stream, can change the frame of
27  * reference for the stream to be that of the last pose received, via the recenter() operation.
28  *
29  * Typical usage:
30  * PoseBias bias;
31  *
32  * bias.setInput(...);
33  * output = bias.getOutput();
34  * bias.setInput(...);
35  * output = bias.getOutput();
36  * bias.setInput(...);
37  * output = bias.getOutput();
38  * bias.recenter();  // Reference frame is now equal to the last input.
39  * output = bias.getOutput();  // This is now the identity pose.
40  *
41  * There doesn't need to be a 1:1 correspondence between setInput() and getOutput() calls.
42  * The initial bias point is identity.
43  *
44  * This implementation is thread-compatible, but not thread-safe.
45  */
46 class PoseBias {
47   public:
48     void setInput(const Pose3f& input);
49 
50     void recenter();
51 
52     Pose3f getOutput() const;
53 
54   private:
55     Pose3f mLastWorldToInput;
56     Pose3f mBiasToWorld;
57 };
58 
59 }  // namespace media
60 }  // namespace android
61