Overlay.h revision 778dccf9a7aa05e0c8df1481ea1d6048bb659667 
1/*
2 * Copyright 2013 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
17#ifndef SCREENRECORD_OVERLAY_H
18#define SCREENRECORD_OVERLAY_H
19
20#include "Program.h"
21#include "TextRenderer.h"
22#include "EglWindow.h"
23
24#include <gui/BufferQueue.h>
25#include <gui/GLConsumer.h>
26#include <utils/Thread.h>
27
28#include <EGL/egl.h>
29
30namespace android {
31
32/*
33 * Overlay "filter".  This sits between the virtual display and the video
34 * encoder.
35 *
36 * Most functions run on a thread created by start().
37 */
38class Overlay : public GLConsumer::FrameAvailableListener, Thread {
39public:
40    Overlay() : Thread(false),
41        mThreadResult(UNKNOWN_ERROR),
42        mState(UNINITIALIZED),
43        mFrameAvailable(false),
44        mExtTextureName(0),
45        mStartMonotonicNsecs(0),
46        mStartRealtimeNsecs(0),
47        mLastFrameNumber(-1),
48        mTotalDroppedFrames(0)
49        {}
50
51    // Creates a thread that performs the overlay.  Pass in the surface that
52    // output will be sent to.
53    //
54    // This creates a dedicated thread for processing frames.
55    //
56    // Returns a reference to the producer side of a new BufferQueue that will
57    // be used by the virtual display.
58    status_t start(const sp<IGraphicBufferProducer>& outputSurface,
59            sp<IGraphicBufferProducer>* pBufferProducer);
60
61    // Stops the thread and releases resources.  It's okay to call this even
62    // if start() was never called.
63    status_t stop();
64
65    // This creates an EGL context and window surface, draws some informative
66    // text on it, swaps the buffer, and then tears the whole thing down.
67    static status_t drawInfoPage(const sp<IGraphicBufferProducer>& outputSurface);
68
69private:
70    Overlay(const Overlay&);
71    Overlay& operator=(const Overlay&);
72
73    // Destruction via RefBase.
74    virtual ~Overlay() { assert(mState == UNINITIALIZED || mState == STOPPED); }
75
76    // Draw the initial info screen.
77    static void doDrawInfoPage(const EglWindow& window,
78            const Program& texRender, TextRenderer& textRenderer);
79
80    // (overrides GLConsumer::FrameAvailableListener method)
81    virtual void onFrameAvailable();
82
83    // (overrides Thread method)
84    virtual bool threadLoop();
85
86    // One-time setup (essentially object construction on the overlay thread).
87    status_t setup_l();
88
89    // Release all resources held.
90    void release_l();
91
92    // Release EGL display, context, surface.
93    void eglRelease_l();
94
95    // Process a frame received from the virtual display.
96    void processFrame_l();
97
98    // Convert a monotonic time stamp into a string with the current time.
99    void getTimeString_l(nsecs_t monotonicNsec, char* buf, size_t bufLen);
100
101    // Guards all fields below.
102    Mutex mMutex;
103
104    // Initialization gate.
105    Condition mStartCond;
106
107    // Thread status, mostly useful during startup.
108    status_t mThreadResult;
109
110    // Overlay thread state.  States advance from left to right; object may
111    // not be restarted.
112    enum { UNINITIALIZED, INIT, RUNNING, STOPPING, STOPPED } mState;
113
114    // Event notification.  Overlay thread sleeps on this until a frame
115    // arrives or it's time to shut down.
116    Condition mEventCond;
117
118    // Set by the FrameAvailableListener callback.
119    bool mFrameAvailable;
120
121    // The surface we send our output to, i.e. the video encoder's input
122    // surface.
123    sp<IGraphicBufferProducer> mOutputSurface;
124
125    // Our queue.  The producer side is passed to the virtual display, the
126    // consumer side feeds into our GLConsumer.
127    sp<BufferQueue> mBufferQueue;
128
129    // This receives frames from the virtual display and makes them available
130    // as an external texture.
131    sp<GLConsumer> mGlConsumer;
132
133    // EGL display / context / surface.
134    EglWindow mEglWindow;
135
136    // GL rendering support.
137    Program mExtTexProgram;
138    Program mTexProgram;
139
140    // Text rendering.
141    TextRenderer mTextRenderer;
142
143    // External texture, updated by GLConsumer.
144    GLuint mExtTextureName;
145
146    // Start time, used to map monotonic to wall-clock time.
147    nsecs_t mStartMonotonicNsecs;
148    nsecs_t mStartRealtimeNsecs;
149
150    // Used for tracking dropped frames.
151    nsecs_t mLastFrameNumber;
152    size_t mTotalDroppedFrames;
153
154    static const char* kPropertyNames[];
155};
156
157}; // namespace android
158
159#endif /*SCREENRECORD_OVERLAY_H*/
160