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1 /*
2  * Copyright 2010, The Android Open Source Project
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *  * Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  *  * Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #ifndef SharedTexture_h
27 #define SharedTexture_h
28 
29 #include "TextureInfo.h"
30 #include <EGL/egl.h>
31 #include <EGL/eglext.h>
32 #include <GLES2/gl2.h>
33 #include <GLES2/gl2ext.h>
34 #include <utils/threads.h>
35 
36 namespace WebCore {
37 
38 /**
39  * SharedTexture is a class that encapsulates all the necessary variables
40  * needed to share a single texture across threads. In the case that threads
41  * communicate using EGL's sharedContext mechanism or do not support the proper
42  * EGLImage extensions the targetTexture, eglImage, and isNewImage variables are
43  * not used.
44  */
45 class SharedTexture {
46 public:
47     // consumer thread functions
48     SharedTexture(SharedTextureMode mode);
49     ~SharedTexture();
50 
51     TextureInfo* lockSource();
52     void releaseSource();
53 
54     TextureInfo* lockTarget();
55     void releaseTarget();
56 
57     // these locks are only used for the methods below
lock()58     void lock() { m_lock.lock(); }
unlock()59     void unlock() { m_lock.unlock(); }
60 
61     void initSourceTexture(); // producer thread only
62     void deleteSourceTexture(); // producer thread only
63     void deleteTargetTexture(); // consumer thread only
getSourceTextureId()64     GLuint getSourceTextureId() { return m_sourceTexture->m_textureId; }
getTargetTextureId()65     GLuint getTargetTextureId() { return m_targetTexture->m_textureId; }
getEGLImage()66     EGLImageKHR getEGLImage() { return m_eglImage; }
67 
68 private:
69     /**
70      * The mutex is used to ensure that the contents of the struct are current across
71      * threads and that only one thread is manipulating the texture at a given time.
72      */
73     android::Mutex m_lock;
74     /**
75      * The texture and its associated metadata that is used by the producer. The
76      * texture is created in the producer's thread and can only be read by the
77      * consumer when the consumer shares the same context as the producer. The
78      * metadata is used to track changes to the texture that would orphan the
79      * target texture and require a new EGLImage to be constructed.
80      */
81     TextureInfo* m_sourceTexture;
82     /**
83      * The target texture stores the id and metadata of the texture that is to be
84      * used by the consumer. In the case where EGLImages are supported this hold
85      * the current eglImage target.
86      */
87     TextureInfo* m_targetTexture;
88     /**
89      * The EGLImage is used to share the texture between EGLContexts on two
90      * different threads. This serves as an alternative to sharing the contexts
91      * but is only used if GL and EGL support the required extensions.
92      */
93     EGLImageKHR m_eglImage;
94     /**
95      * This flag is used to determine if the eglImage has been updated. This
96      * signals the consumer thread to rebind the targetTexture to the new image.
97      */
98     bool m_isNewImage;
99     /**
100      * The sync allows the consumer to release the lock prior to the commands
101      * executing on the GPU. Prior to releasing the lock the consumer creates
102      * a sync object and stores it here. After locking the texture the client
103      * must check that the sync has completed prior to manipulating the texture.
104      * This value is only used if the proper EGL extensions are supported.
105      */
106     EGLSyncKHR m_syncObject;
107 
108     EGLDisplay m_display;
109 
110     bool m_supportsEGLImage;
111     bool m_supportsEGLFenceSyncKHR;
112 
113     SharedTextureMode m_sharedTextureMode;
114 };
115 
116 } // namespace WebCore
117 
118 #endif // SharedTexture_h
119