GLConsumer.h revision 2d14a0ed4f5861bfa67e9db138ffdc70d2d5e6e4
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 {
55public:
56    enum { TEXTURE_EXTERNAL = 0x8D65 }; // GL_TEXTURE_EXTERNAL_OES
57    typedef ConsumerBase::FrameAvailableListener FrameAvailableListener;
58
59    // GLConsumer constructs a new GLConsumer object. If the constructor with
60    // the tex parameter is used, tex indicates the name of the OpenGL ES
61    // texture to which images are to be streamed. texTarget specifies the
62    // OpenGL ES texture target to which the texture will be bound in
63    // updateTexImage. useFenceSync specifies whether fences should be used to
64    // synchronize access to buffers if that behavior is enabled at
65    // compile-time.
66    //
67    // A GLConsumer may be detached from one OpenGL ES context and then
68    // attached to a different context using the detachFromContext and
69    // attachToContext methods, respectively. The intention of these methods is
70    // purely to allow a GLConsumer to be transferred from one consumer
71    // context to another. If such a transfer is not needed there is no
72    // requirement that either of these methods be called.
73    //
74    // If the constructor with the tex parameter is used, the GLConsumer is
75    // created in a state where it is considered attached to an OpenGL ES
76    // context for the purposes of the attachToContext and detachFromContext
77    // methods. However, despite being considered "attached" to a context, the
78    // specific OpenGL ES context doesn't get latched until the first call to
79    // updateTexImage. After that point, all calls to updateTexImage must be
80    // made with the same OpenGL ES context current.
81    //
82    // If the constructor without the tex parameter is used, the GLConsumer is
83    // created in a detached state, and attachToContext must be called before
84    // calls to updateTexImage.
85    GLConsumer(const sp<IGraphicBufferConsumer>& bq,
86            uint32_t tex, uint32_t texureTarget, bool useFenceSync,
87            bool isControlledByApp);
88
89    GLConsumer(const sp<IGraphicBufferConsumer>& bq, uint32_t texureTarget,
90            bool useFenceSync, bool isControlledByApp);
91
92    // updateTexImage acquires the most recently queued buffer, and sets the
93    // image contents of the target texture to it.
94    //
95    // This call may only be made while the OpenGL ES context to which the
96    // target texture belongs is bound to the calling thread.
97    //
98    // This calls doGLFenceWait to ensure proper synchronization.
99    status_t updateTexImage();
100
101    // releaseTexImage releases the texture acquired in updateTexImage().
102    // This is intended to be used in single buffer mode.
103    //
104    // This call may only be made while the OpenGL ES context to which the
105    // target texture belongs is bound to the calling thread.
106    status_t releaseTexImage();
107
108    // setReleaseFence stores a fence that will signal when the current buffer
109    // is no longer being read. This fence will be returned to the producer
110    // when the current buffer is released by updateTexImage(). Multiple
111    // fences can be set for a given buffer; they will be merged into a single
112    // union fence.
113    void setReleaseFence(const sp<Fence>& fence);
114
115    // setDefaultMaxBufferCount sets the default limit on the maximum number
116    // of buffers that will be allocated at one time. The image producer may
117    // override the limit.
118    status_t setDefaultMaxBufferCount(int bufferCount);
119
120    // getTransformMatrix retrieves the 4x4 texture coordinate transform matrix
121    // associated with the texture image set by the most recent call to
122    // updateTexImage.
123    //
124    // This transform matrix maps 2D homogeneous texture coordinates of the form
125    // (s, t, 0, 1) with s and t in the inclusive range [0, 1] to the texture
126    // coordinate that should be used to sample that location from the texture.
127    // Sampling the texture outside of the range of this transform is undefined.
128    //
129    // This transform is necessary to compensate for transforms that the stream
130    // content producer may implicitly apply to the content. By forcing users of
131    // a GLConsumer to apply this transform we avoid performing an extra
132    // copy of the data that would be needed to hide the transform from the
133    // user.
134    //
135    // The matrix is stored in column-major order so that it may be passed
136    // directly to OpenGL ES via the glLoadMatrixf or glUniformMatrix4fv
137    // functions.
138    void getTransformMatrix(float mtx[16]);
139
140    // getTimestamp retrieves the timestamp associated with the texture image
141    // set by the most recent call to updateTexImage.
142    //
143    // The timestamp is in nanoseconds, and is monotonically increasing. Its
144    // other semantics (zero point, etc) are source-dependent and should be
145    // documented by the source.
146    int64_t getTimestamp();
147
148    // getFrameNumber retrieves the frame number associated with the texture
149    // image set by the most recent call to updateTexImage.
150    //
151    // The frame number is an incrementing counter set to 0 at the creation of
152    // the BufferQueue associated with this consumer.
153    int64_t getFrameNumber();
154
155    // setDefaultBufferSize is used to set the size of buffers returned by
156    // requestBuffers when a with and height of zero is requested.
157    // A call to setDefaultBufferSize() may trigger requestBuffers() to
158    // be called from the client.
159    // The width and height parameters must be no greater than the minimum of
160    // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
161    // An error due to invalid dimensions might not be reported until
162    // updateTexImage() is called.
163    status_t setDefaultBufferSize(uint32_t width, uint32_t height);
164
165    // setFilteringEnabled sets whether the transform matrix should be computed
166    // for use with bilinear filtering.
167    void setFilteringEnabled(bool enabled);
168
169    // getCurrentBuffer returns the buffer associated with the current image.
170    sp<GraphicBuffer> getCurrentBuffer() const;
171
172    // getCurrentTextureTarget returns the texture target of the current
173    // texture as returned by updateTexImage().
174    uint32_t getCurrentTextureTarget() const;
175
176    // getCurrentCrop returns the cropping rectangle of the current buffer.
177    Rect getCurrentCrop() const;
178
179    // getCurrentTransform returns the transform of the current buffer.
180    uint32_t getCurrentTransform() const;
181
182    // getCurrentScalingMode returns the scaling mode of the current buffer.
183    uint32_t getCurrentScalingMode() const;
184
185    // getCurrentFence returns the fence indicating when the current buffer is
186    // ready to be read from.
187    sp<Fence> getCurrentFence() const;
188
189    // doGLFenceWait inserts a wait command into the OpenGL ES command stream
190    // to ensure that it is safe for future OpenGL ES commands to access the
191    // current texture buffer.
192    status_t doGLFenceWait() const;
193
194    // set the name of the GLConsumer that will be used to identify it in
195    // log messages.
196    void setName(const String8& name);
197
198    // These functions call the corresponding BufferQueue implementation
199    // so the refactoring can proceed smoothly
200    status_t setDefaultBufferFormat(uint32_t defaultFormat);
201    status_t setConsumerUsageBits(uint32_t usage);
202    status_t setTransformHint(uint32_t hint);
203
204    // detachFromContext detaches the GLConsumer from the calling thread's
205    // current OpenGL ES context.  This context must be the same as the context
206    // that was current for previous calls to updateTexImage.
207    //
208    // Detaching a GLConsumer from an OpenGL ES context will result in the
209    // deletion of the OpenGL ES texture object into which the images were being
210    // streamed.  After a GLConsumer has been detached from the OpenGL ES
211    // context calls to updateTexImage will fail returning INVALID_OPERATION
212    // until the GLConsumer is attached to a new OpenGL ES context using the
213    // attachToContext method.
214    status_t detachFromContext();
215
216    // attachToContext attaches a GLConsumer that is currently in the
217    // 'detached' state to the current OpenGL ES context.  A GLConsumer is
218    // in the 'detached' state iff detachFromContext has successfully been
219    // called and no calls to attachToContext have succeeded since the last
220    // detachFromContext call.  Calls to attachToContext made on a
221    // GLConsumer that is not in the 'detached' state will result in an
222    // INVALID_OPERATION error.
223    //
224    // The tex argument specifies the OpenGL ES texture object name in the
225    // new context into which the image contents will be streamed.  A successful
226    // call to attachToContext will result in this texture object being bound to
227    // the texture target and populated with the image contents that were
228    // current at the time of the last call to detachFromContext.
229    status_t attachToContext(uint32_t tex);
230
231protected:
232
233    // abandonLocked overrides the ConsumerBase method to clear
234    // mCurrentTextureImage in addition to the ConsumerBase behavior.
235    virtual void abandonLocked();
236
237    // dumpLocked overrides the ConsumerBase method to dump GLConsumer-
238    // specific info in addition to the ConsumerBase behavior.
239    virtual void dumpLocked(String8& result, const char* prefix) const;
240
241    // acquireBufferLocked overrides the ConsumerBase method to update the
242    // mEglSlots array in addition to the ConsumerBase behavior.
243    virtual status_t acquireBufferLocked(BufferQueue::BufferItem *item,
244        nsecs_t presentWhen);
245
246    // releaseBufferLocked overrides the ConsumerBase method to update the
247    // mEglSlots array in addition to the ConsumerBase.
248    virtual status_t releaseBufferLocked(int slot,
249            const sp<GraphicBuffer> graphicBuffer,
250            EGLDisplay display, EGLSyncKHR eglFence);
251
252    status_t releaseBufferLocked(int slot,
253            const sp<GraphicBuffer> graphicBuffer, EGLSyncKHR eglFence) {
254        return releaseBufferLocked(slot, graphicBuffer, mEglDisplay, eglFence);
255    }
256
257    static bool isExternalFormat(uint32_t format);
258
259    // This releases the buffer in the slot referenced by mCurrentTexture,
260    // then updates state to refer to the BufferItem, which must be a
261    // newly-acquired buffer.
262    status_t updateAndReleaseLocked(const BufferQueue::BufferItem& item);
263
264    // Binds mTexName and the current buffer to mTexTarget.  Uses
265    // mCurrentTexture if it's set, mCurrentTextureImage if not.  If the
266    // bind succeeds, this calls doGLFenceWait.
267    status_t bindTextureImageLocked();
268
269    // Gets the current EGLDisplay and EGLContext values, and compares them
270    // to mEglDisplay and mEglContext.  If the fields have been previously
271    // set, the values must match; if not, the fields are set to the current
272    // values.
273    // The contextCheck argument is used to ensure that a GL context is
274    // properly set; when set to false, the check is not performed.
275    status_t checkAndUpdateEglStateLocked(bool contextCheck = false);
276
277private:
278    // EglImage is a utility class for tracking and creating EGLImageKHRs. There
279    // is primarily just one image per slot, but there is also special cases:
280    //  - For releaseTexImage, we use a debug image (mReleasedTexImage)
281    //  - After freeBuffer, we must still keep the current image/buffer
282    // Reference counting EGLImages lets us handle all these cases easily while
283    // also only creating new EGLImages from buffers when required.
284    class EglImage : public LightRefBase<EglImage>  {
285    public:
286        EglImage(sp<GraphicBuffer> graphicBuffer);
287
288        // createIfNeeded creates an EGLImage if required (we haven't created
289        // one yet, or the EGLDisplay or crop-rect has changed).
290        status_t createIfNeeded(EGLDisplay display,
291                                const Rect& cropRect,
292                                bool forceCreate = false);
293
294        // This calls glEGLImageTargetTexture2DOES to bind the image to the
295        // texture in the specified texture target.
296        void bindToTextureTarget(uint32_t texTarget);
297
298        const sp<GraphicBuffer>& graphicBuffer() { return mGraphicBuffer; }
299        const native_handle* graphicBufferHandle() {
300            return mGraphicBuffer == NULL ? NULL : mGraphicBuffer->handle;
301        }
302
303    private:
304        // Only allow instantiation using ref counting.
305        friend class LightRefBase<EglImage>;
306        virtual ~EglImage();
307
308        // createImage creates a new EGLImage from a GraphicBuffer.
309        EGLImageKHR createImage(EGLDisplay dpy,
310                const sp<GraphicBuffer>& graphicBuffer, const Rect& crop);
311
312        // Disallow copying
313        EglImage(const EglImage& rhs);
314        void operator = (const EglImage& rhs);
315
316        // mGraphicBuffer is the buffer that was used to create this image.
317        sp<GraphicBuffer> mGraphicBuffer;
318
319        // mEglImage is the EGLImage created from mGraphicBuffer.
320        EGLImageKHR mEglImage;
321
322        // mEGLDisplay is the EGLDisplay that was used to create mEglImage.
323        EGLDisplay mEglDisplay;
324
325        // mCropRect is the crop rectangle passed to EGL when mEglImage
326        // was created.
327        Rect mCropRect;
328    };
329
330    // freeBufferLocked frees up the given buffer slot. If the slot has been
331    // initialized this will release the reference to the GraphicBuffer in that
332    // slot and destroy the EGLImage in that slot.  Otherwise it has no effect.
333    //
334    // This method must be called with mMutex locked.
335    virtual void freeBufferLocked(int slotIndex);
336
337    // computeCurrentTransformMatrixLocked computes the transform matrix for the
338    // current texture.  It uses mCurrentTransform and the current GraphicBuffer
339    // to compute this matrix and stores it in mCurrentTransformMatrix.
340    // mCurrentTextureImage must not be NULL.
341    void computeCurrentTransformMatrixLocked();
342
343    // doGLFenceWaitLocked inserts a wait command into the OpenGL ES command
344    // stream to ensure that it is safe for future OpenGL ES commands to
345    // access the current texture buffer.
346    status_t doGLFenceWaitLocked() const;
347
348    // syncForReleaseLocked performs the synchronization needed to release the
349    // current slot from an OpenGL ES context.  If needed it will set the
350    // current slot's fence to guard against a producer accessing the buffer
351    // before the outstanding accesses have completed.
352    status_t syncForReleaseLocked(EGLDisplay dpy);
353
354    // returns a graphic buffer used when the texture image has been released
355    static sp<GraphicBuffer> getDebugTexImageBuffer();
356
357    // The default consumer usage flags that GLConsumer always sets on its
358    // BufferQueue instance; these will be OR:d with any additional flags passed
359    // from the GLConsumer user. In particular, GLConsumer will always
360    // consume buffers as hardware textures.
361    static const uint32_t DEFAULT_USAGE_FLAGS = GraphicBuffer::USAGE_HW_TEXTURE;
362
363    // mCurrentTextureImage is the EglImage/buffer of the current texture. It's
364    // possible that this buffer is not associated with any buffer slot, so we
365    // must track it separately in order to support the getCurrentBuffer method.
366    sp<EglImage> mCurrentTextureImage;
367
368    // mCurrentCrop is the crop rectangle that applies to the current texture.
369    // It gets set each time updateTexImage is called.
370    Rect mCurrentCrop;
371
372    // mCurrentTransform is the transform identifier for the current texture. It
373    // gets set each time updateTexImage is called.
374    uint32_t mCurrentTransform;
375
376    // mCurrentScalingMode is the scaling mode for the current texture. It gets
377    // set each time updateTexImage is called.
378    uint32_t mCurrentScalingMode;
379
380    // mCurrentFence is the fence received from BufferQueue in updateTexImage.
381    sp<Fence> mCurrentFence;
382
383    // mCurrentTransformMatrix is the transform matrix for the current texture.
384    // It gets computed by computeTransformMatrix each time updateTexImage is
385    // called.
386    float mCurrentTransformMatrix[16];
387
388    // mCurrentTimestamp is the timestamp for the current texture. It
389    // gets set each time updateTexImage is called.
390    int64_t mCurrentTimestamp;
391
392    // mCurrentFrameNumber is the frame counter for the current texture.
393    // It gets set each time updateTexImage is called.
394    int64_t mCurrentFrameNumber;
395
396    uint32_t mDefaultWidth, mDefaultHeight;
397
398    // mFilteringEnabled indicates whether the transform matrix is computed for
399    // use with bilinear filtering. It defaults to true and is changed by
400    // setFilteringEnabled().
401    bool mFilteringEnabled;
402
403    // mTexName is the name of the OpenGL texture to which streamed images will
404    // be bound when updateTexImage is called. It is set at construction time
405    // and can be changed with a call to attachToContext.
406    uint32_t mTexName;
407
408    // mUseFenceSync indicates whether creation of the EGL_KHR_fence_sync
409    // extension should be used to prevent buffers from being dequeued before
410    // it's safe for them to be written. It gets set at construction time and
411    // never changes.
412    const bool mUseFenceSync;
413
414    // mTexTarget is the GL texture target with which the GL texture object is
415    // associated.  It is set in the constructor and never changed.  It is
416    // almost always GL_TEXTURE_EXTERNAL_OES except for one use case in Android
417    // Browser.  In that case it is set to GL_TEXTURE_2D to allow
418    // glCopyTexSubImage to read from the texture.  This is a hack to work
419    // around a GL driver limitation on the number of FBO attachments, which the
420    // browser's tile cache exceeds.
421    const uint32_t mTexTarget;
422
423    // EGLSlot contains the information and object references that
424    // GLConsumer maintains about a BufferQueue buffer slot.
425    struct EglSlot {
426        EglSlot() : mEglFence(EGL_NO_SYNC_KHR) {}
427
428        // mEglImage is the EGLImage created from mGraphicBuffer.
429        sp<EglImage> mEglImage;
430
431        // mFence is the EGL sync object that must signal before the buffer
432        // associated with this buffer slot may be dequeued. It is initialized
433        // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based
434        // on a compile-time option) set to a new sync object in updateTexImage.
435        EGLSyncKHR mEglFence;
436    };
437
438    // mEglDisplay is the EGLDisplay with which this GLConsumer is currently
439    // associated.  It is intialized to EGL_NO_DISPLAY and gets set to the
440    // current display when updateTexImage is called for the first time and when
441    // attachToContext is called.
442    EGLDisplay mEglDisplay;
443
444    // mEglContext is the OpenGL ES context with which this GLConsumer is
445    // currently associated.  It is initialized to EGL_NO_CONTEXT and gets set
446    // to the current GL context when updateTexImage is called for the first
447    // time and when attachToContext is called.
448    EGLContext mEglContext;
449
450    // mEGLSlots stores the buffers that have been allocated by the BufferQueue
451    // for each buffer slot.  It is initialized to null pointers, and gets
452    // filled in with the result of BufferQueue::acquire when the
453    // client dequeues a buffer from a
454    // slot that has not yet been used. The buffer allocated to a slot will also
455    // be replaced if the requested buffer usage or geometry differs from that
456    // of the buffer allocated to a slot.
457    EglSlot mEglSlots[BufferQueue::NUM_BUFFER_SLOTS];
458
459    // mCurrentTexture is the buffer slot index of the buffer that is currently
460    // bound to the OpenGL texture. It is initialized to INVALID_BUFFER_SLOT,
461    // indicating that no buffer slot is currently bound to the texture. Note,
462    // however, that a value of INVALID_BUFFER_SLOT does not necessarily mean
463    // that no buffer is bound to the texture. A call to setBufferCount will
464    // reset mCurrentTexture to INVALID_BUFFER_SLOT.
465    int mCurrentTexture;
466
467    // mAttached indicates whether the ConsumerBase is currently attached to
468    // an OpenGL ES context.  For legacy reasons, this is initialized to true,
469    // indicating that the ConsumerBase is considered to be attached to
470    // whatever context is current at the time of the first updateTexImage call.
471    // It is set to false by detachFromContext, and then set to true again by
472    // attachToContext.
473    bool mAttached;
474
475    // protects static initialization
476    static Mutex sStaticInitLock;
477
478    // mReleasedTexImageBuffer is a dummy buffer used when in single buffer
479    // mode and releaseTexImage() has been called
480    static sp<GraphicBuffer> sReleasedTexImageBuffer;
481    sp<EglImage> mReleasedTexImage;
482};
483
484// ----------------------------------------------------------------------------
485}; // namespace android
486
487#endif // ANDROID_GUI_CONSUMER_H
488