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1 /*
2  * Copyright (C) 2021 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 <chrono>
19 #include <condition_variable>
20 #include <limits>
21 #include <memory>
22 #include <mutex>
23 #include <thread>
24 
25 #include <media/HeadTrackingProcessor.h>
26 #include <media/SensorPoseProvider.h>
27 #include <media/VectorRecorder.h>
28 
29 namespace android {
30 
31 /**
32  * This class encapsulates the logic for pose processing, intended for driving a spatializer effect.
33  * This includes integration with the Sensor sub-system for retrieving sensor data, doing all the
34  * necessary processing, etc.
35  *
36  * Calculations happen on a dedicated thread and published to the client via the Listener interface.
37  * A calculation may be triggered in one of two ways:
38  * - By calling calculateAsync() - calculation will be kicked off in the background.
39  * - By setting a timeout in the ctor, a calculation will be triggered after the timeout elapsed
40  *   from the last calculateAsync() call.
41  *
42  * This class is thread-safe.
43  */
44 class SpatializerPoseController : private media::SensorPoseProvider::Listener {
45   public:
46     static constexpr int32_t INVALID_SENSOR = media::SensorPoseProvider::INVALID_HANDLE;
47 
48     /**
49      * Listener interface for getting pose and mode updates.
50      * Methods will always be invoked from a designated thread.
51      */
52     class Listener {
53       public:
54         virtual ~Listener() = default;
55 
56         virtual void onHeadToStagePose(const media::Pose3f&) = 0;
57         virtual void onActualModeChange(media::HeadTrackingMode) = 0;
58     };
59 
60     /**
61      * Ctor.
62      * sensorPeriod determines how often to receive updates from the sensors (input rate).
63      * maxUpdatePeriod determines how often to produce an output when calculateAsync() isn't
64      * invoked; passing nullopt means an output is never produced.
65      */
66     SpatializerPoseController(Listener* listener, std::chrono::microseconds sensorPeriod,
67                                std::optional<std::chrono::microseconds> maxUpdatePeriod);
68 
69     /** Dtor. */
70     ~SpatializerPoseController();
71 
72     /**
73      * Set the sensor that is to be used for head-tracking.
74      * INVALID_SENSOR can be used to disable head-tracking.
75      */
76     void setHeadSensor(int32_t sensor);
77 
78     /**
79      * Set the sensor that is to be used for screen-tracking.
80      * INVALID_SENSOR can be used to disable screen-tracking.
81      */
82     void setScreenSensor(int32_t sensor);
83 
84     /** Sets the desired head-tracking mode. */
85     void setDesiredMode(media::HeadTrackingMode mode);
86 
87     /**
88      * Set the screen-to-stage pose, used in all modes.
89      */
90     void setScreenToStagePose(const media::Pose3f& screenToStage);
91 
92     /**
93      * Sets the display orientation.
94      * Orientation is expressed in the angle of rotation from the physical "up" side of the screen
95      * to the logical "up" side of the content displayed the screen. Counterclockwise angles, as
96      * viewed while facing the screen are positive.
97      */
98     void setDisplayOrientation(float physicalToLogicalAngle);
99 
100     /**
101      * This causes the current poses for both the head and screen to be considered "center".
102      */
103     void recenter();
104 
105     /**
106      * This call triggers the recalculation of the output and the invocation of the relevant
107      * callbacks. This call is async and the callbacks will be triggered shortly after.
108      */
109     void calculateAsync();
110 
111     /**
112      * Blocks until calculation and invocation of the respective callbacks has happened at least
113      * once. Do not call from within callbacks.
114      */
115     void waitUntilCalculated();
116 
117     // convert fields to a printable string
118     std::string toString(unsigned level) const;
119 
120   private:
121     mutable std::timed_mutex mMutex;
122     Listener* const mListener;
123     const std::chrono::microseconds mSensorPeriod;
124     std::unique_ptr<media::HeadTrackingProcessor> mProcessor;
125     int32_t mHeadSensor = media::SensorPoseProvider::INVALID_HANDLE;
126     int32_t mScreenSensor = media::SensorPoseProvider::INVALID_HANDLE;
127     std::optional<media::HeadTrackingMode> mActualMode;
128     std::condition_variable_any mCondVar;
129     bool mShouldCalculate = true;
130     bool mShouldExit = false;
131     bool mCalculated = false;
132 
133     media::VectorRecorder mHeadSensorRecorder{
134         8 /* vectorSize */, std::chrono::seconds(1), 10 /* maxLogLine */,
135         { 3, 6, 7 } /* delimiterIdx */};
136     media::VectorRecorder mHeadSensorDurableRecorder{
137         8 /* vectorSize */, std::chrono::minutes(1), 10 /* maxLogLine */,
138         { 3, 6, 7 } /* delimiterIdx */};
139 
140     media::VectorRecorder mScreenSensorRecorder{
141         4 /* vectorSize */, std::chrono::seconds(1), 10 /* maxLogLine */,
142         { 3 } /* delimiterIdx */};
143     media::VectorRecorder mScreenSensorDurableRecorder{
144         4 /* vectorSize */, std::chrono::minutes(1), 10 /* maxLogLine */,
145         { 3 } /* delimiterIdx */};
146 
147     // Next to last variable as releasing this stops the callbacks
148     std::unique_ptr<media::SensorPoseProvider> mPoseProvider;
149 
150     // It's important that mThread is the last variable in this class
151     // since we starts mThread in initializer list
152     std::thread mThread;
153 
154     void onPose(int64_t timestamp, int32_t sensor, const media::Pose3f& pose,
155                 const std::optional<media::Twist3f>& twist, bool isNewReference) override;
156 
157     /**
158      * Calculates the new outputs and updates internal state. Must be called with the lock held.
159      * Returns values that should be passed to the respective callbacks.
160      */
161     std::tuple<media::Pose3f, std::optional<media::HeadTrackingMode>> calculate_l();
162 };
163 
164 }  // namespace android
165