GLConsumer.h revision d171da973de3c6b30263011334fdcd916739144f
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_CONSUMER_H
18#define ANDROID_GUI_CONSUMER_H
19
20#include <EGL/egl.h>
21#include <EGL/eglext.h>
22
23#include <gui/IGraphicBufferProducer.h>
24#include <gui/BufferQueue.h>
25#include <gui/ConsumerBase.h>
26
27#include <ui/GraphicBuffer.h>
28
29#include <utils/String8.h>
30#include <utils/Vector.h>
31#include <utils/threads.h>
32
33namespace android {
34// ----------------------------------------------------------------------------
35
36
37class String8;
38
39/*
40 * GLConsumer consumes buffers of graphics data from a BufferQueue,
41 * and makes them available to OpenGL as a texture.
42 *
43 * A typical usage pattern is to set up the GLConsumer with the
44 * desired options, and call updateTexImage() when a new frame is desired.
45 * If a new frame is available, the texture will be updated.  If not,
46 * the previous contents are retained.
47 *
48 * By default, the texture is attached to the GL_TEXTURE_EXTERNAL_OES
49 * texture target, in the EGL context of the first thread that calls
50 * updateTexImage().
51 *
52 * This class was previously called SurfaceTexture.
53 */
54class GLConsumer : public ConsumerBase {
55protected:
56    enum { TEXTURE_EXTERNAL = 0x8D65 }; // GL_TEXTURE_EXTERNAL_OES
57public:
58    typedef ConsumerBase::FrameAvailableListener FrameAvailableListener;
59
60    // GLConsumer constructs a new GLConsumer object. tex indicates the
61    // name of the OpenGL ES texture to which images are to be streamed.
62    // allowSynchronousMode specifies whether or not synchronous mode can be
63    // enabled. texTarget specifies the OpenGL ES texture target to which the
64    // texture will be bound in updateTexImage. useFenceSync specifies whether
65    // fences should be used to synchronize access to buffers if that behavior
66    // is enabled at compile-time. A custom bufferQueue can be specified
67    // if behavior for queue/dequeue/connect etc needs to be customized.
68    // Otherwise a default BufferQueue will be created and used.
69    //
70    // For legacy reasons, the GLConsumer is created in a state where it is
71    // considered attached to an OpenGL ES context for the purposes of the
72    // attachToContext and detachFromContext methods. However, despite being
73    // considered "attached" to a context, the specific OpenGL ES context
74    // doesn't get latched until the first call to updateTexImage. After that
75    // point, all calls to updateTexImage must be made with the same OpenGL ES
76    // context current.
77    //
78    // A GLConsumer may be detached from one OpenGL ES context and then
79    // attached to a different context using the detachFromContext and
80    // attachToContext methods, respectively. The intention of these methods is
81    // purely to allow a GLConsumer to be transferred from one consumer
82    // context to another. If such a transfer is not needed there is no
83    // requirement that either of these methods be called.
84    GLConsumer(const sp<IGraphicBufferConsumer>& bq,
85            uint32_t tex, uint32_t texureTarget = TEXTURE_EXTERNAL,
86            bool useFenceSync = true, bool isControlledByApp = false);
87
88    // updateTexImage acquires the most recently queued buffer, and sets the
89    // image contents of the target texture to it.
90    //
91    // This call may only be made while the OpenGL ES context to which the
92    // target texture belongs is bound to the calling thread.
93    //
94    // This calls doGLFenceWait to ensure proper synchronization.
95    status_t updateTexImage();
96
97    // releaseTexImage releases the texture acquired in updateTexImage().
98    // This is intended to be used in single buffer mode.
99    //
100    // This call may only be made while the OpenGL ES context to which the
101    // target texture belongs is bound to the calling thread.
102    status_t releaseTexImage();
103
104    // setReleaseFence stores a fence that will signal when the current buffer
105    // is no longer being read. This fence will be returned to the producer
106    // when the current buffer is released by updateTexImage(). Multiple
107    // fences can be set for a given buffer; they will be merged into a single
108    // union fence.
109    void setReleaseFence(const sp<Fence>& fence);
110
111    // setDefaultMaxBufferCount sets the default limit on the maximum number
112    // of buffers that will be allocated at one time. The image producer may
113    // override the limit.
114    status_t setDefaultMaxBufferCount(int bufferCount);
115
116    // getTransformMatrix retrieves the 4x4 texture coordinate transform matrix
117    // associated with the texture image set by the most recent call to
118    // updateTexImage.
119    //
120    // This transform matrix maps 2D homogeneous texture coordinates of the form
121    // (s, t, 0, 1) with s and t in the inclusive range [0, 1] to the texture
122    // coordinate that should be used to sample that location from the texture.
123    // Sampling the texture outside of the range of this transform is undefined.
124    //
125    // This transform is necessary to compensate for transforms that the stream
126    // content producer may implicitly apply to the content. By forcing users of
127    // a GLConsumer to apply this transform we avoid performing an extra
128    // copy of the data that would be needed to hide the transform from the
129    // user.
130    //
131    // The matrix is stored in column-major order so that it may be passed
132    // directly to OpenGL ES via the glLoadMatrixf or glUniformMatrix4fv
133    // functions.
134    void getTransformMatrix(float mtx[16]);
135
136    // getTimestamp retrieves the timestamp associated with the texture image
137    // set by the most recent call to updateTexImage.
138    //
139    // The timestamp is in nanoseconds, and is monotonically increasing. Its
140    // other semantics (zero point, etc) are source-dependent and should be
141    // documented by the source.
142    int64_t getTimestamp();
143
144    // getFrameNumber retrieves the frame number associated with the texture
145    // image set by the most recent call to updateTexImage.
146    //
147    // The frame number is an incrementing counter set to 0 at the creation of
148    // the BufferQueue associated with this consumer.
149    int64_t getFrameNumber();
150
151    // setDefaultBufferSize is used to set the size of buffers returned by
152    // requestBuffers when a with and height of zero is requested.
153    // A call to setDefaultBufferSize() may trigger requestBuffers() to
154    // be called from the client.
155    // The width and height parameters must be no greater than the minimum of
156    // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
157    // An error due to invalid dimensions might not be reported until
158    // updateTexImage() is called.
159    status_t setDefaultBufferSize(uint32_t width, uint32_t height);
160
161    // setFilteringEnabled sets whether the transform matrix should be computed
162    // for use with bilinear filtering.
163    void setFilteringEnabled(bool enabled);
164
165    // getCurrentBuffer returns the buffer associated with the current image.
166    sp<GraphicBuffer> getCurrentBuffer() const;
167
168    // getCurrentTextureTarget returns the texture target of the current
169    // texture as returned by updateTexImage().
170    uint32_t getCurrentTextureTarget() const;
171
172    // getCurrentCrop returns the cropping rectangle of the current buffer.
173    Rect getCurrentCrop() const;
174
175    // getCurrentTransform returns the transform of the current buffer.
176    uint32_t getCurrentTransform() const;
177
178    // getCurrentScalingMode returns the scaling mode of the current buffer.
179    uint32_t getCurrentScalingMode() const;
180
181    // getCurrentFence returns the fence indicating when the current buffer is
182    // ready to be read from.
183    sp<Fence> getCurrentFence() const;
184
185    // doGLFenceWait inserts a wait command into the OpenGL ES command stream
186    // to ensure that it is safe for future OpenGL ES commands to access the
187    // current texture buffer.
188    status_t doGLFenceWait() const;
189
190    // set the name of the GLConsumer 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
200    // detachFromContext detaches the GLConsumer from the calling thread's
201    // current OpenGL ES context.  This context must be the same as the context
202    // that was current for previous calls to updateTexImage.
203    //
204    // Detaching a GLConsumer from an OpenGL ES context will result in the
205    // deletion of the OpenGL ES texture object into which the images were being
206    // streamed.  After a GLConsumer has been detached from the OpenGL ES
207    // context calls to updateTexImage will fail returning INVALID_OPERATION
208    // until the GLConsumer is attached to a new OpenGL ES context using the
209    // attachToContext method.
210    status_t detachFromContext();
211
212    // attachToContext attaches a GLConsumer that is currently in the
213    // 'detached' state to the current OpenGL ES context.  A GLConsumer is
214    // in the 'detached' state iff detachFromContext has successfully been
215    // called and no calls to attachToContext have succeeded since the last
216    // detachFromContext call.  Calls to attachToContext made on a
217    // GLConsumer that is not in the 'detached' state will result in an
218    // INVALID_OPERATION error.
219    //
220    // The tex argument specifies the OpenGL ES texture object name in the
221    // new context into which the image contents will be streamed.  A successful
222    // call to attachToContext will result in this texture object being bound to
223    // the texture target and populated with the image contents that were
224    // current at the time of the last call to detachFromContext.
225    status_t attachToContext(uint32_t tex);
226
227protected:
228
229    // abandonLocked overrides the ConsumerBase method to clear
230    // mCurrentTextureBuf in addition to the ConsumerBase behavior.
231    virtual void abandonLocked();
232
233    // dumpLocked overrides the ConsumerBase method to dump GLConsumer-
234    // specific info in addition to the ConsumerBase behavior.
235    virtual void dumpLocked(String8& result, const char* prefix) const;
236
237    // acquireBufferLocked overrides the ConsumerBase method to update the
238    // mEglSlots array in addition to the ConsumerBase behavior.
239    virtual status_t acquireBufferLocked(BufferQueue::BufferItem *item,
240        nsecs_t presentWhen);
241
242    // releaseBufferLocked overrides the ConsumerBase method to update the
243    // mEglSlots array in addition to the ConsumerBase.
244    virtual status_t releaseBufferLocked(int slot,
245            const sp<GraphicBuffer> graphicBuffer,
246            EGLDisplay display, EGLSyncKHR eglFence);
247
248    status_t releaseBufferLocked(int slot,
249            const sp<GraphicBuffer> graphicBuffer, EGLSyncKHR eglFence) {
250        return releaseBufferLocked(slot, graphicBuffer, mEglDisplay, eglFence);
251    }
252
253    static bool isExternalFormat(uint32_t format);
254
255    // This releases the buffer in the slot referenced by mCurrentTexture,
256    // then updates state to refer to the BufferItem, which must be a
257    // newly-acquired buffer.
258    status_t updateAndReleaseLocked(const BufferQueue::BufferItem& item);
259
260    // Binds mTexName and the current buffer to mTexTarget.  Uses
261    // mCurrentTexture if it's set, mCurrentTextureBuf if not.  If the
262    // bind succeeds, this calls doGLFenceWait.
263    status_t bindTextureImageLocked();
264
265    // Gets the current EGLDisplay and EGLContext values, and compares them
266    // to mEglDisplay and mEglContext.  If the fields have been previously
267    // set, the values must match; if not, the fields are set to the current
268    // values.
269    // The contextCheck argument is used to ensure that a GL context is
270    // properly set; when set to false, the check is not performed.
271    status_t checkAndUpdateEglStateLocked(bool contextCheck = false);
272
273private:
274    // createImage creates a new EGLImage from a GraphicBuffer.
275    EGLImageKHR createImage(EGLDisplay dpy,
276            const sp<GraphicBuffer>& graphicBuffer);
277
278    // freeBufferLocked frees up the given buffer slot.  If the slot has been
279    // initialized this will release the reference to the GraphicBuffer in that
280    // slot and destroy the EGLImage in that slot.  Otherwise it has no effect.
281    //
282    // This method must be called with mMutex locked.
283    virtual void freeBufferLocked(int slotIndex);
284
285    // computeCurrentTransformMatrixLocked computes the transform matrix for the
286    // current texture.  It uses mCurrentTransform and the current GraphicBuffer
287    // to compute this matrix and stores it in mCurrentTransformMatrix.
288    // mCurrentTextureBuf must not be NULL.
289    void computeCurrentTransformMatrixLocked();
290
291    // doGLFenceWaitLocked inserts a wait command into the OpenGL ES command
292    // stream to ensure that it is safe for future OpenGL ES commands to
293    // access the current texture buffer.
294    status_t doGLFenceWaitLocked() const;
295
296    // syncForReleaseLocked performs the synchronization needed to release the
297    // current slot from an OpenGL ES context.  If needed it will set the
298    // current slot's fence to guard against a producer accessing the buffer
299    // before the outstanding accesses have completed.
300    status_t syncForReleaseLocked(EGLDisplay dpy);
301
302    // Normally, when we bind a buffer to a texture target, we bind a buffer
303    // that is referenced by an entry in mEglSlots.  In some situations we
304    // have a buffer in mCurrentTextureBuf, but no corresponding entry for
305    // it in our slot array.  bindUnslottedBuffer handles that situation by
306    // binding the buffer without touching the EglSlots.
307    status_t bindUnslottedBufferLocked(EGLDisplay dpy);
308
309    // returns a graphic buffer used when the texture image has been released
310    static sp<GraphicBuffer> getDebugTexImageBuffer();
311
312    // The default consumer usage flags that GLConsumer always sets on its
313    // BufferQueue instance; these will be OR:d with any additional flags passed
314    // from the GLConsumer user. In particular, GLConsumer will always
315    // consume buffers as hardware textures.
316    static const uint32_t DEFAULT_USAGE_FLAGS = GraphicBuffer::USAGE_HW_TEXTURE;
317
318    // mCurrentTextureBuf is the graphic buffer of the current texture. It's
319    // possible that this buffer is not associated with any buffer slot, so we
320    // must track it separately in order to support the getCurrentBuffer method.
321    sp<GraphicBuffer> mCurrentTextureBuf;
322
323    // mCurrentCrop is the crop rectangle that applies to the current texture.
324    // It gets set each time updateTexImage is called.
325    Rect mCurrentCrop;
326
327    // mCurrentTransform is the transform identifier for the current texture. It
328    // gets set each time updateTexImage is called.
329    uint32_t mCurrentTransform;
330
331    // mCurrentScalingMode is the scaling mode for the current texture. It gets
332    // set each time updateTexImage is called.
333    uint32_t mCurrentScalingMode;
334
335    // mCurrentFence is the fence received from BufferQueue in updateTexImage.
336    sp<Fence> mCurrentFence;
337
338    // mCurrentTransformMatrix is the transform matrix for the current texture.
339    // It gets computed by computeTransformMatrix each time updateTexImage is
340    // called.
341    float mCurrentTransformMatrix[16];
342
343    // mCurrentTimestamp is the timestamp for the current texture. It
344    // gets set each time updateTexImage is called.
345    int64_t mCurrentTimestamp;
346
347    // mCurrentFrameNumber is the frame counter for the current texture.
348    // It gets set each time updateTexImage is called.
349    int64_t mCurrentFrameNumber;
350
351    uint32_t mDefaultWidth, mDefaultHeight;
352
353    // mFilteringEnabled indicates whether the transform matrix is computed for
354    // use with bilinear filtering. It defaults to true and is changed by
355    // setFilteringEnabled().
356    bool mFilteringEnabled;
357
358    // mTexName is the name of the OpenGL texture to which streamed images will
359    // be bound when updateTexImage is called. It is set at construction time
360    // and can be changed with a call to attachToContext.
361    uint32_t mTexName;
362
363    // mUseFenceSync indicates whether creation of the EGL_KHR_fence_sync
364    // extension should be used to prevent buffers from being dequeued before
365    // it's safe for them to be written. It gets set at construction time and
366    // never changes.
367    const bool mUseFenceSync;
368
369    // mTexTarget is the GL texture target with which the GL texture object is
370    // associated.  It is set in the constructor and never changed.  It is
371    // almost always GL_TEXTURE_EXTERNAL_OES except for one use case in Android
372    // Browser.  In that case it is set to GL_TEXTURE_2D to allow
373    // glCopyTexSubImage to read from the texture.  This is a hack to work
374    // around a GL driver limitation on the number of FBO attachments, which the
375    // browser's tile cache exceeds.
376    const uint32_t mTexTarget;
377
378    // EGLSlot contains the information and object references that
379    // GLConsumer maintains about a BufferQueue buffer slot.
380    struct EglSlot {
381        EglSlot()
382        : mEglImage(EGL_NO_IMAGE_KHR),
383          mEglFence(EGL_NO_SYNC_KHR) {
384        }
385
386        // mEglImage is the EGLImage created from mGraphicBuffer.
387        EGLImageKHR mEglImage;
388
389        // mFence is the EGL sync object that must signal before the buffer
390        // associated with this buffer slot may be dequeued. It is initialized
391        // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based
392        // on a compile-time option) set to a new sync object in updateTexImage.
393        EGLSyncKHR mEglFence;
394    };
395
396    // mEglDisplay is the EGLDisplay with which this GLConsumer is currently
397    // associated.  It is intialized to EGL_NO_DISPLAY and gets set to the
398    // current display when updateTexImage is called for the first time and when
399    // attachToContext is called.
400    EGLDisplay mEglDisplay;
401
402    // mEglContext is the OpenGL ES context with which this GLConsumer is
403    // currently associated.  It is initialized to EGL_NO_CONTEXT and gets set
404    // to the current GL context when updateTexImage is called for the first
405    // time and when attachToContext is called.
406    EGLContext mEglContext;
407
408    // mEGLSlots stores the buffers that have been allocated by the BufferQueue
409    // for each buffer slot.  It is initialized to null pointers, and gets
410    // filled in with the result of BufferQueue::acquire when the
411    // client dequeues a buffer from a
412    // slot that has not yet been used. The buffer allocated to a slot will also
413    // be replaced if the requested buffer usage or geometry differs from that
414    // of the buffer allocated to a slot.
415    EglSlot mEglSlots[BufferQueue::NUM_BUFFER_SLOTS];
416
417    // mCurrentTexture is the buffer slot index of the buffer that is currently
418    // bound to the OpenGL texture. It is initialized to INVALID_BUFFER_SLOT,
419    // indicating that no buffer slot is currently bound to the texture. Note,
420    // however, that a value of INVALID_BUFFER_SLOT does not necessarily mean
421    // that no buffer is bound to the texture. A call to setBufferCount will
422    // reset mCurrentTexture to INVALID_BUFFER_SLOT.
423    int mCurrentTexture;
424
425    // mAttached indicates whether the ConsumerBase is currently attached to
426    // an OpenGL ES context.  For legacy reasons, this is initialized to true,
427    // indicating that the ConsumerBase is considered to be attached to
428    // whatever context is current at the time of the first updateTexImage call.
429    // It is set to false by detachFromContext, and then set to true again by
430    // attachToContext.
431    bool mAttached;
432
433    // protects static initialization
434    static Mutex sStaticInitLock;
435
436    // mReleasedTexImageBuffer is a dummy buffer used when in single buffer
437    // mode and releaseTexImage() has been called
438    static sp<GraphicBuffer> sReleasedTexImageBuffer;
439};
440
441// ----------------------------------------------------------------------------
442}; // namespace android
443
444#endif // ANDROID_GUI_CONSUMER_H
445