SurfaceTexture.h revision ef19414bd8b77a26f5751f3845be79025a8263fe
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#include <GLES2/gl2ext.h>
24
25#include <gui/ISurfaceTexture.h>
26#include <gui/BufferQueue.h>
27
28#include <ui/GraphicBuffer.h>
29
30#include <utils/String8.h>
31#include <utils/Vector.h>
32#include <utils/threads.h>
33
34#define ANDROID_GRAPHICS_SURFACETEXTURE_JNI_ID "mSurfaceTexture"
35
36namespace android {
37// ----------------------------------------------------------------------------
38
39
40class String8;
41
42class SurfaceTexture : public virtual RefBase,
43        protected BufferQueue::ConsumerListener {
44public:
45    struct FrameAvailableListener : public virtual RefBase {
46        // onFrameAvailable() is called each time an additional frame becomes
47        // available for consumption. This means that frames that are queued
48        // while in asynchronous mode only trigger the callback if no previous
49        // frames are pending. Frames queued while in synchronous mode always
50        // trigger the callback.
51        //
52        // This is called without any lock held and can be called concurrently
53        // by multiple threads.
54        virtual void onFrameAvailable() = 0;
55    };
56
57    // SurfaceTexture constructs a new SurfaceTexture object. tex indicates the
58    // name of the OpenGL ES texture to which images are to be streamed.
59    // allowSynchronousMode specifies whether or not synchronous mode can be
60    // enabled. texTarget specifies the OpenGL ES texture target to which the
61    // texture will be bound in updateTexImage. useFenceSync specifies whether
62    // fences should be used to synchronize access to buffers if that behavior
63    // is enabled at compile-time. A custom bufferQueue can be specified
64    // if behavior for queue/dequeue/connect etc needs to be customized.
65    // Otherwise a default BufferQueue will be created and used.
66    //
67    // For legacy reasons, the SurfaceTexture is created in a state where it is
68    // considered attached to an OpenGL ES context for the purposes of the
69    // attachToContext and detachFromContext methods. However, despite being
70    // considered "attached" to a context, the specific OpenGL ES context
71    // doesn't get latched until the first call to updateTexImage. After that
72    // point, all calls to updateTexImage must be made with the same OpenGL ES
73    // context current.
74    //
75    // A SurfaceTexture may be detached from one OpenGL ES context and then
76    // attached to a different context using the detachFromContext and
77    // attachToContext methods, respectively. The intention of these methods is
78    // purely to allow a SurfaceTexture to be transferred from one consumer
79    // context to another. If such a transfer is not needed there is no
80    // requirement that either of these methods be called.
81    SurfaceTexture(GLuint tex, bool allowSynchronousMode = true,
82            GLenum texTarget = GL_TEXTURE_EXTERNAL_OES, bool useFenceSync = true,
83            const sp<BufferQueue> &bufferQueue = 0);
84
85    virtual ~SurfaceTexture();
86
87    // updateTexImage sets the image contents of the target texture to that of
88    // the most recently queued buffer.
89    //
90    // This call may only be made while the OpenGL ES context to which the
91    // target texture belongs is bound to the calling thread.
92    status_t updateTexImage();
93
94    // setReleaseFence stores a fence file descriptor that will signal when the
95    // current buffer is no longer being read. This fence will be returned to
96    // the producer when the current buffer is released by updateTexImage().
97    // Multiple fences can be set for a given buffer; they will be merged into
98    // a single union fence. The SurfaceTexture will close the file descriptor
99    // when finished with it.
100    void setReleaseFence(int fenceFd);
101
102    // setBufferCountServer set the buffer count. If the client has requested
103    // a buffer count using setBufferCount, the server-buffer count will
104    // take effect once the client sets the count back to zero.
105    status_t setBufferCountServer(int bufferCount);
106
107    // getTransformMatrix retrieves the 4x4 texture coordinate transform matrix
108    // associated with the texture image set by the most recent call to
109    // updateTexImage.
110    //
111    // This transform matrix maps 2D homogeneous texture coordinates of the form
112    // (s, t, 0, 1) with s and t in the inclusive range [0, 1] to the texture
113    // coordinate that should be used to sample that location from the texture.
114    // Sampling the texture outside of the range of this transform is undefined.
115    //
116    // This transform is necessary to compensate for transforms that the stream
117    // content producer may implicitly apply to the content. By forcing users of
118    // a SurfaceTexture to apply this transform we avoid performing an extra
119    // copy of the data that would be needed to hide the transform from the
120    // user.
121    //
122    // The matrix is stored in column-major order so that it may be passed
123    // directly to OpenGL ES via the glLoadMatrixf or glUniformMatrix4fv
124    // functions.
125    void getTransformMatrix(float mtx[16]);
126
127    // getTimestamp retrieves the timestamp associated with the texture image
128    // set by the most recent call to updateTexImage.
129    //
130    // The timestamp is in nanoseconds, and is monotonically increasing. Its
131    // other semantics (zero point, etc) are source-dependent and should be
132    // documented by the source.
133    int64_t getTimestamp();
134
135    // setFrameAvailableListener sets the listener object that will be notified
136    // when a new frame becomes available.
137    void setFrameAvailableListener(const sp<FrameAvailableListener>& listener);
138
139    // getAllocator retrieves the binder object that must be referenced as long
140    // as the GraphicBuffers dequeued from this SurfaceTexture are referenced.
141    // Holding this binder reference prevents SurfaceFlinger from freeing the
142    // buffers before the client is done with them.
143    sp<IBinder> getAllocator();
144
145    // setDefaultBufferSize is used to set the size of buffers returned by
146    // requestBuffers when a with and height of zero is requested.
147    // A call to setDefaultBufferSize() may trigger requestBuffers() to
148    // be called from the client.
149    // The width and height parameters must be no greater than the minimum of
150    // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
151    // An error due to invalid dimensions might not be reported until
152    // updateTexImage() is called.
153    status_t setDefaultBufferSize(uint32_t width, uint32_t height);
154
155    // setFilteringEnabled sets whether the transform matrix should be computed
156    // for use with bilinear filtering.
157    void setFilteringEnabled(bool enabled);
158
159    // getCurrentBuffer returns the buffer associated with the current image.
160    sp<GraphicBuffer> getCurrentBuffer() const;
161
162    // getCurrentTextureTarget returns the texture target of the current
163    // texture as returned by updateTexImage().
164    GLenum getCurrentTextureTarget() const;
165
166    // getCurrentCrop returns the cropping rectangle of the current buffer.
167    Rect getCurrentCrop() const;
168
169    // getCurrentTransform returns the transform of the current buffer.
170    uint32_t getCurrentTransform() const;
171
172    // getCurrentScalingMode returns the scaling mode of the current buffer.
173    uint32_t getCurrentScalingMode() const;
174
175    // isSynchronousMode returns whether the SurfaceTexture is currently in
176    // synchronous mode.
177    bool isSynchronousMode() const;
178
179    // abandon frees all the buffers and puts the SurfaceTexture into the
180    // 'abandoned' state.  Once put in this state the SurfaceTexture can never
181    // leave it.  When in the 'abandoned' state, all methods of the
182    // ISurfaceTexture interface will fail with the NO_INIT error.
183    //
184    // Note that while calling this method causes all the buffers to be freed
185    // from the perspective of the the SurfaceTexture, if there are additional
186    // references on the buffers (e.g. if a buffer is referenced by a client or
187    // by OpenGL ES as a texture) then those buffer will remain allocated.
188    void abandon();
189
190    // set the name of the SurfaceTexture that will be used to identify it in
191    // log messages.
192    void setName(const String8& name);
193
194    // These functions call the corresponding BufferQueue implementation
195    // so the refactoring can proceed smoothly
196    status_t setDefaultBufferFormat(uint32_t defaultFormat);
197    status_t setConsumerUsageBits(uint32_t usage);
198    status_t setTransformHint(uint32_t hint);
199    virtual status_t setSynchronousMode(bool enabled);
200
201    // getBufferQueue returns the BufferQueue object to which this
202    // SurfaceTexture is connected.
203    sp<BufferQueue> getBufferQueue() const;
204
205    // detachFromContext detaches the SurfaceTexture from the calling thread's
206    // current OpenGL ES context.  This context must be the same as the context
207    // that was current for previous calls to updateTexImage.
208    //
209    // Detaching a SurfaceTexture from an OpenGL ES context will result in the
210    // deletion of the OpenGL ES texture object into which the images were being
211    // streamed.  After a SurfaceTexture has been detached from the OpenGL ES
212    // context calls to updateTexImage will fail returning INVALID_OPERATION
213    // until the SurfaceTexture is attached to a new OpenGL ES context using the
214    // attachToContext method.
215    status_t detachFromContext();
216
217    // attachToContext attaches a SurfaceTexture that is currently in the
218    // 'detached' state to the current OpenGL ES context.  A SurfaceTexture is
219    // in the 'detached' state iff detachFromContext has successfully been
220    // called and no calls to attachToContext have succeeded since the last
221    // detachFromContext call.  Calls to attachToContext made on a
222    // SurfaceTexture that is not in the 'detached' state will result in an
223    // INVALID_OPERATION error.
224    //
225    // The tex argument specifies the OpenGL ES texture object name in the
226    // new context into which the image contents will be streamed.  A successful
227    // call to attachToContext will result in this texture object being bound to
228    // the texture target and populated with the image contents that were
229    // current at the time of the last call to detachFromContext.
230    status_t attachToContext(GLuint tex);
231
232    // dump our state in a String
233    virtual void dump(String8& result) const;
234    virtual void dump(String8& result, const char* prefix, char* buffer, size_t SIZE) const;
235
236protected:
237
238    // Implementation of the BufferQueue::ConsumerListener interface.  These
239    // calls are used to notify the SurfaceTexture of asynchronous events in the
240    // BufferQueue.
241    virtual void onFrameAvailable();
242    virtual void onBuffersReleased();
243
244    static bool isExternalFormat(uint32_t format);
245
246private:
247    // this version of updateTexImage() takes a functor used to reject or not
248    // the newly acquired buffer.
249    // this API is TEMPORARY and intended to be used by SurfaceFlinger only,
250    // which is why class Layer is made a friend of SurfaceTexture below.
251    class BufferRejecter {
252        friend class SurfaceTexture;
253        virtual bool reject(const sp<GraphicBuffer>& buf,
254                const BufferQueue::BufferItem& item) = 0;
255    protected:
256        virtual ~BufferRejecter() { }
257    };
258    friend class Layer;
259    status_t updateTexImage(BufferRejecter* rejecter);
260
261    // createImage creates a new EGLImage from a GraphicBuffer.
262    EGLImageKHR createImage(EGLDisplay dpy,
263            const sp<GraphicBuffer>& graphicBuffer);
264
265    // freeBufferLocked frees up the given buffer slot.  If the slot has been
266    // initialized this will release the reference to the GraphicBuffer in that
267    // slot and destroy the EGLImage in that slot.  Otherwise it has no effect.
268    //
269    // This method must be called with mMutex locked.
270    void freeBufferLocked(int slotIndex);
271
272    // computeCurrentTransformMatrix computes the transform matrix for the
273    // current texture.  It uses mCurrentTransform and the current GraphicBuffer
274    // to compute this matrix and stores it in mCurrentTransformMatrix.
275    void computeCurrentTransformMatrix();
276
277    // syncForReleaseLocked performs the synchronization needed to release the
278    // current slot from an OpenGL ES context.  If needed it will set the
279    // current slot's fence to guard against a producer accessing the buffer
280    // before the outstanding accesses have completed.
281    status_t syncForReleaseLocked(EGLDisplay dpy);
282
283    // The default consumer usage flags that SurfaceTexture always sets on its
284    // BufferQueue instance; these will be OR:d with any additional flags passed
285    // from the SurfaceTexture user. In particular, SurfaceTexture will always
286    // consume buffers as hardware textures.
287    static const uint32_t DEFAULT_USAGE_FLAGS = GraphicBuffer::USAGE_HW_TEXTURE;
288
289    // mCurrentTextureBuf is the graphic buffer of the current texture. It's
290    // possible that this buffer is not associated with any buffer slot, so we
291    // must track it separately in order to support the getCurrentBuffer method.
292    sp<GraphicBuffer> mCurrentTextureBuf;
293
294    // mCurrentCrop is the crop rectangle that applies to the current texture.
295    // It gets set each time updateTexImage is called.
296    Rect mCurrentCrop;
297
298    // mCurrentTransform is the transform identifier for the current texture. It
299    // gets set each time updateTexImage is called.
300    uint32_t mCurrentTransform;
301
302    // mCurrentScalingMode is the scaling mode for the current texture. It gets
303    // set to each time updateTexImage is called.
304    uint32_t mCurrentScalingMode;
305
306    // mCurrentTransformMatrix is the transform matrix for the current texture.
307    // It gets computed by computeTransformMatrix each time updateTexImage is
308    // called.
309    float mCurrentTransformMatrix[16];
310
311    // mCurrentTimestamp is the timestamp for the current texture. It
312    // gets set each time updateTexImage is called.
313    int64_t mCurrentTimestamp;
314
315    uint32_t mDefaultWidth, mDefaultHeight;
316
317    // mFilteringEnabled indicates whether the transform matrix is computed for
318    // use with bilinear filtering. It defaults to true and is changed by
319    // setFilteringEnabled().
320    bool mFilteringEnabled;
321
322    // mTexName is the name of the OpenGL texture to which streamed images will
323    // be bound when updateTexImage is called. It is set at construction time
324    // and can be changed with a call to attachToContext.
325    GLuint mTexName;
326
327    // mUseFenceSync indicates whether creation of the EGL_KHR_fence_sync
328    // extension should be used to prevent buffers from being dequeued before
329    // it's safe for them to be written. It gets set at construction time and
330    // never changes.
331    const bool mUseFenceSync;
332
333    // mTexTarget is the GL texture target with which the GL texture object is
334    // associated.  It is set in the constructor and never changed.  It is
335    // almost always GL_TEXTURE_EXTERNAL_OES except for one use case in Android
336    // Browser.  In that case it is set to GL_TEXTURE_2D to allow
337    // glCopyTexSubImage to read from the texture.  This is a hack to work
338    // around a GL driver limitation on the number of FBO attachments, which the
339    // browser's tile cache exceeds.
340    const GLenum mTexTarget;
341
342    // EGLSlot contains the information and object references that
343    // SurfaceTexture maintains about a BufferQueue buffer slot.
344    struct EGLSlot {
345        EGLSlot()
346        : mEglImage(EGL_NO_IMAGE_KHR),
347          mFence(EGL_NO_SYNC_KHR) {
348        }
349
350        sp<GraphicBuffer> mGraphicBuffer;
351
352        // mEglImage is the EGLImage created from mGraphicBuffer.
353        EGLImageKHR mEglImage;
354
355        // mFence is the EGL sync object that must signal before the buffer
356        // associated with this buffer slot may be dequeued. It is initialized
357        // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based
358        // on a compile-time option) set to a new sync object in updateTexImage.
359        EGLSyncKHR mFence;
360
361        // mReleaseFence is a fence which will signal when the buffer
362        // associated with this buffer slot is no longer being used by the
363        // consumer and can be overwritten. The buffer can be dequeued before
364        // the fence signals; the producer is responsible for delaying writes
365        // until it signals.
366        sp<Fence> mReleaseFence;
367    };
368
369    // mEglDisplay is the EGLDisplay with which this SurfaceTexture is currently
370    // associated.  It is intialized to EGL_NO_DISPLAY and gets set to the
371    // current display when updateTexImage is called for the first time and when
372    // attachToContext is called.
373    EGLDisplay mEglDisplay;
374
375    // mEglContext is the OpenGL ES context with which this SurfaceTexture is
376    // currently associated.  It is initialized to EGL_NO_CONTEXT and gets set
377    // to the current GL context when updateTexImage is called for the first
378    // time and when attachToContext is called.
379    EGLContext mEglContext;
380
381    // mEGLSlots stores the buffers that have been allocated by the BufferQueue
382    // for each buffer slot.  It is initialized to null pointers, and gets
383    // filled in with the result of BufferQueue::acquire when the
384    // client dequeues a buffer from a
385    // slot that has not yet been used. The buffer allocated to a slot will also
386    // be replaced if the requested buffer usage or geometry differs from that
387    // of the buffer allocated to a slot.
388    EGLSlot mEGLSlots[BufferQueue::NUM_BUFFER_SLOTS];
389
390    // mAbandoned indicates that the BufferQueue will no longer be used to
391    // consume images buffers pushed to it using the ISurfaceTexture interface.
392    // It is initialized to false, and set to true in the abandon method.  A
393    // BufferQueue that has been abandoned will return the NO_INIT error from
394    // all ISurfaceTexture methods capable of returning an error.
395    bool mAbandoned;
396
397    // mName is a string used to identify the SurfaceTexture in log messages.
398    // It can be set by the setName method.
399    String8 mName;
400
401    // mFrameAvailableListener is the listener object that will be called when a
402    // new frame becomes available. If it is not NULL it will be called from
403    // queueBuffer.
404    sp<FrameAvailableListener> mFrameAvailableListener;
405
406    // mCurrentTexture is the buffer slot index of the buffer that is currently
407    // bound to the OpenGL texture. It is initialized to INVALID_BUFFER_SLOT,
408    // indicating that no buffer slot is currently bound to the texture. Note,
409    // however, that a value of INVALID_BUFFER_SLOT does not necessarily mean
410    // that no buffer is bound to the texture. A call to setBufferCount will
411    // reset mCurrentTexture to INVALID_BUFFER_SLOT.
412    int mCurrentTexture;
413
414    // The SurfaceTexture has-a BufferQueue and is responsible for creating this object
415    // if none is supplied
416    sp<BufferQueue> mBufferQueue;
417
418    // mAttached indicates whether the SurfaceTexture is currently attached to
419    // an OpenGL ES context.  For legacy reasons, this is initialized to true,
420    // indicating that the SurfaceTexture is considered to be attached to
421    // whatever context is current at the time of the first updateTexImage call.
422    // It is set to false by detachFromContext, and then set to true again by
423    // attachToContext.
424    bool mAttached;
425
426    // mMutex is the mutex used to prevent concurrent access to the member
427    // variables of SurfaceTexture objects. It must be locked whenever the
428    // member variables are accessed.
429    mutable Mutex mMutex;
430};
431
432// ----------------------------------------------------------------------------
433}; // namespace android
434
435#endif // ANDROID_GUI_SURFACETEXTURE_H
436