SurfaceTexture.h revision 67eedd74ab78c2bfed9fcdc74947b97289254ca4 
1/*
2 * Copyright (C) 2010 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 ANDROID_GUI_SURFACETEXTURE_H
18#define ANDROID_GUI_SURFACETEXTURE_H
19
20#include <EGL/egl.h>
21#include <EGL/eglext.h>
22#include <GLES2/gl2.h>
23
24#include <gui/ISurfaceTexture.h>
25
26#include <ui/GraphicBuffer.h>
27
28#include <utils/threads.h>
29
30#define ANDROID_GRAPHICS_SURFACETEXTURE_JNI_ID "mSurfaceTexture"
31
32namespace android {
33// ----------------------------------------------------------------------------
34
35class SurfaceTexture : public BnSurfaceTexture {
36public:
37    enum { MIN_BUFFER_SLOTS = 3 };
38    enum { NUM_BUFFER_SLOTS = 32 };
39
40    // tex indicates the name OpenGL texture to which images are to be streamed.
41    // This texture name cannot be changed once the SurfaceTexture is created.
42    SurfaceTexture(GLuint tex);
43
44    virtual ~SurfaceTexture();
45
46    // setBufferCount updates the number of available buffer slots.  After
47    // calling this all buffer slots are both unallocated and owned by the
48    // SurfaceTexture object (i.e. they are not owned by the client).
49    virtual status_t setBufferCount(int bufferCount);
50
51    virtual sp<GraphicBuffer> requestBuffer(int buf, uint32_t w, uint32_t h,
52            uint32_t format, uint32_t usage);
53
54    // dequeueBuffer gets the next buffer slot index for the client to use. If a
55    // buffer slot is available then that slot index is written to the location
56    // pointed to by the buf argument and a status of OK is returned.  If no
57    // slot is available then a status of -EBUSY is returned and buf is
58    // unmodified.
59    virtual status_t dequeueBuffer(int *buf);
60
61    virtual status_t queueBuffer(int buf);
62    virtual void cancelBuffer(int buf);
63    virtual status_t setCrop(const Rect& reg);
64    virtual status_t setTransform(uint32_t transform);
65
66    // updateTexImage sets the image contents of the target texture to that of
67    // the most recently queued buffer.
68    //
69    // This call may only be made while the OpenGL ES context to which the
70    // target texture belongs is bound to the calling thread.
71    status_t updateTexImage();
72
73private:
74
75    // freeAllBuffers frees the resources (both GraphicBuffer and EGLImage) for
76    // all slots.
77    void freeAllBuffers();
78
79    // createImage creates a new EGLImage from a GraphicBuffer.
80    EGLImageKHR createImage(EGLDisplay dpy,
81            const sp<GraphicBuffer>& graphicBuffer);
82
83    enum { INVALID_BUFFER_SLOT = -1 };
84
85    struct BufferSlot {
86        // mGraphicBuffer points to the buffer allocated for this slot or is NULL
87        // if no buffer has been allocated.
88        sp<GraphicBuffer> mGraphicBuffer;
89
90        // mEglImage is the EGLImage created from mGraphicBuffer.
91        EGLImageKHR mEglImage;
92
93        // mEglDisplay is the EGLDisplay used to create mEglImage.
94        EGLDisplay mEglDisplay;
95
96        // mOwnedByClient indicates whether the slot is currently accessible to a
97        // client and should not be used by the SurfaceTexture object. It gets
98        // set to true when dequeueBuffer returns the slot and is reset to false
99        // when the client calls either queueBuffer or cancelBuffer on the slot.
100        bool mOwnedByClient;
101    };
102
103    // mSlots is the array of buffer slots that must be mirrored on the client
104    // side. This allows buffer ownership to be transferred between the client
105    // and server without sending a GraphicBuffer over binder. The entire array
106    // is initialized to NULL at construction time, and buffers are allocated
107    // for a slot when requestBuffer is called with that slot's index.
108    BufferSlot mSlots[NUM_BUFFER_SLOTS];
109
110    // mBufferCount is the number of buffer slots that the client and server
111    // must maintain. It defaults to MIN_BUFFER_SLOTS and can be changed by
112    // calling setBufferCount.
113    int mBufferCount;
114
115    // mCurrentTexture is the buffer slot index of the buffer that is currently
116    // bound to the OpenGL texture. It is initialized to INVALID_BUFFER_SLOT,
117    // indicating that no buffer slot is currently bound to the texture. Note,
118    // however, that a value of INVALID_BUFFER_SLOT does not necessarily mean
119    // that no buffer is bound to the texture. A call to setBufferCount will
120    // reset mCurrentTexture to INVALID_BUFFER_SLOT.
121    int mCurrentTexture;
122
123    // mLastQueued is the buffer slot index of the most recently enqueued buffer.
124    // At construction time it is initialized to INVALID_BUFFER_SLOT, and is
125    // updated each time queueBuffer is called.
126    int mLastQueued;
127
128    // mTexName is the name of the OpenGL texture to which streamed images will
129    // be bound when updateTexImage is called. It is set at construction time
130    // changed with a call to setTexName.
131    const GLuint mTexName;
132
133    // mMutex is the mutex used to prevent concurrent access to the member
134    // variables of SurfaceTexture objects. It must be locked whenever the
135    // member variables are accessed.
136    Mutex mMutex;
137};
138
139// ----------------------------------------------------------------------------
140}; // namespace android
141
142#endif // ANDROID_GUI_SURFACETEXTURE_H
143