GLConsumer.h revision 2adaf04fab35cf47c824d74d901b54094e01ccd3
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#include <GLES2/gl2.h>
23#include <GLES2/gl2ext.h>
24
25#include <gui/IGraphicBufferProducer.h>
26#include <gui/BufferQueue.h>
27#include <gui/ConsumerBase.h>
28
29#include <ui/GraphicBuffer.h>
30
31#include <utils/String8.h>
32#include <utils/Vector.h>
33#include <utils/threads.h>
34
35#define ANDROID_GRAPHICS_SURFACETEXTURE_JNI_ID "mSurfaceTexture"
36#define ANDROID_GRAPHICS_FRAMEAVAILABLELISTENER_JNI_ID \
37                                         "mFrameAvailableListener"
38
39namespace android {
40// ----------------------------------------------------------------------------
41
42
43class String8;
44
45/*
46 * GLConsumer consumes buffers of graphics data from a BufferQueue,
47 * and makes them available to OpenGL as a texture.
48 *
49 * A typical usage pattern is to set up the GLConsumer with the
50 * desired options, and call updateTexImage() when a new frame is desired.
51 * If a new frame is available, the texture will be updated.  If not,
52 * the previous contents are retained.
53 *
54 * By default, the texture is attached to the GL_TEXTURE_EXTERNAL_OES
55 * texture target, in the EGL context of the first thread that calls
56 * updateTexImage().
57 *
58 * This class was previously called SurfaceTexture.
59 */
60class GLConsumer : public ConsumerBase {
61public:
62    typedef ConsumerBase::FrameAvailableListener FrameAvailableListener;
63
64    // GLConsumer constructs a new GLConsumer object. tex indicates the
65    // name of the OpenGL ES texture to which images are to be streamed.
66    // allowSynchronousMode specifies whether or not synchronous mode can be
67    // enabled. texTarget specifies the OpenGL ES texture target to which the
68    // texture will be bound in updateTexImage. useFenceSync specifies whether
69    // fences should be used to synchronize access to buffers if that behavior
70    // is enabled at compile-time. A custom bufferQueue can be specified
71    // if behavior for queue/dequeue/connect etc needs to be customized.
72    // Otherwise a default BufferQueue will be created and used.
73    //
74    // For legacy reasons, the GLConsumer is created in a state where it is
75    // considered attached to an OpenGL ES context for the purposes of the
76    // attachToContext and detachFromContext methods. However, despite being
77    // considered "attached" to a context, the specific OpenGL ES context
78    // doesn't get latched until the first call to updateTexImage. After that
79    // point, all calls to updateTexImage must be made with the same OpenGL ES
80    // context current.
81    //
82    // A GLConsumer may be detached from one OpenGL ES context and then
83    // attached to a different context using the detachFromContext and
84    // attachToContext methods, respectively. The intention of these methods is
85    // purely to allow a GLConsumer to be transferred from one consumer
86    // context to another. If such a transfer is not needed there is no
87    // requirement that either of these methods be called.
88    GLConsumer(GLuint tex, bool allowSynchronousMode = true,
89            GLenum texTarget = GL_TEXTURE_EXTERNAL_OES, bool useFenceSync = true,
90            const sp<BufferQueue> &bufferQueue = 0);
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    // setReleaseFence stores a fence file descriptor that will signal when the
102    // current buffer is no longer being read. This fence will be returned to
103    // the producer when the current buffer is released by updateTexImage().
104    // Multiple fences can be set for a given buffer; they will be merged into
105    // a single union fence. The GLConsumer will close the file descriptor
106    // when finished with it.
107    void setReleaseFence(int fenceFd);
108
109    // setDefaultMaxBufferCount sets the default limit on the maximum number
110    // of buffers that will be allocated at one time. The image producer may
111    // override the limit.
112    status_t setDefaultMaxBufferCount(int bufferCount);
113
114    // getTransformMatrix retrieves the 4x4 texture coordinate transform matrix
115    // associated with the texture image set by the most recent call to
116    // updateTexImage.
117    //
118    // This transform matrix maps 2D homogeneous texture coordinates of the form
119    // (s, t, 0, 1) with s and t in the inclusive range [0, 1] to the texture
120    // coordinate that should be used to sample that location from the texture.
121    // Sampling the texture outside of the range of this transform is undefined.
122    //
123    // This transform is necessary to compensate for transforms that the stream
124    // content producer may implicitly apply to the content. By forcing users of
125    // a GLConsumer to apply this transform we avoid performing an extra
126    // copy of the data that would be needed to hide the transform from the
127    // user.
128    //
129    // The matrix is stored in column-major order so that it may be passed
130    // directly to OpenGL ES via the glLoadMatrixf or glUniformMatrix4fv
131    // functions.
132    void getTransformMatrix(float mtx[16]);
133
134    // getTimestamp retrieves the timestamp associated with the texture image
135    // set by the most recent call to updateTexImage.
136    //
137    // The timestamp is in nanoseconds, and is monotonically increasing. Its
138    // other semantics (zero point, etc) are source-dependent and should be
139    // documented by the source.
140    int64_t getTimestamp();
141
142    // setDefaultBufferSize is used to set the size of buffers returned by
143    // requestBuffers when a with and height of zero is requested.
144    // A call to setDefaultBufferSize() may trigger requestBuffers() to
145    // be called from the client.
146    // The width and height parameters must be no greater than the minimum of
147    // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
148    // An error due to invalid dimensions might not be reported until
149    // updateTexImage() is called.
150    status_t setDefaultBufferSize(uint32_t width, uint32_t height);
151
152    // setFilteringEnabled sets whether the transform matrix should be computed
153    // for use with bilinear filtering.
154    void setFilteringEnabled(bool enabled);
155
156    // getCurrentBuffer returns the buffer associated with the current image.
157    sp<GraphicBuffer> getCurrentBuffer() const;
158
159    // getCurrentTextureTarget returns the texture target of the current
160    // texture as returned by updateTexImage().
161    GLenum getCurrentTextureTarget() const;
162
163    // getCurrentCrop returns the cropping rectangle of the current buffer.
164    Rect getCurrentCrop() const;
165
166    // getCurrentTransform returns the transform of the current buffer.
167    uint32_t getCurrentTransform() const;
168
169    // getCurrentScalingMode returns the scaling mode of the current buffer.
170    uint32_t getCurrentScalingMode() const;
171
172    // getCurrentFence returns the fence indicating when the current buffer is
173    // ready to be read from.
174    sp<Fence> getCurrentFence() const;
175
176    // doGLFenceWait inserts a wait command into the OpenGL ES command stream
177    // to ensure that it is safe for future OpenGL ES commands to access the
178    // current texture buffer.
179    status_t doGLFenceWait() const;
180
181    // isSynchronousMode returns whether the GLConsumer is currently in
182    // synchronous mode.
183    bool isSynchronousMode() const;
184
185    // set the name of the GLConsumer that will be used to identify it in
186    // log messages.
187    void setName(const String8& name);
188
189    // These functions call the corresponding BufferQueue implementation
190    // so the refactoring can proceed smoothly
191    status_t setDefaultBufferFormat(uint32_t defaultFormat);
192    status_t setConsumerUsageBits(uint32_t usage);
193    status_t setTransformHint(uint32_t hint);
194    virtual status_t setSynchronousMode(bool enabled);
195
196    // getBufferQueue returns the BufferQueue object to which this
197    // GLConsumer is connected.
198    sp<BufferQueue> getBufferQueue() const {
199        return mBufferQueue;
200    }
201
202    // detachFromContext detaches the GLConsumer from the calling thread's
203    // current OpenGL ES context.  This context must be the same as the context
204    // that was current for previous calls to updateTexImage.
205    //
206    // Detaching a GLConsumer from an OpenGL ES context will result in the
207    // deletion of the OpenGL ES texture object into which the images were being
208    // streamed.  After a GLConsumer has been detached from the OpenGL ES
209    // context calls to updateTexImage will fail returning INVALID_OPERATION
210    // until the GLConsumer is attached to a new OpenGL ES context using the
211    // attachToContext method.
212    status_t detachFromContext();
213
214    // attachToContext attaches a GLConsumer that is currently in the
215    // 'detached' state to the current OpenGL ES context.  A GLConsumer is
216    // in the 'detached' state iff detachFromContext has successfully been
217    // called and no calls to attachToContext have succeeded since the last
218    // detachFromContext call.  Calls to attachToContext made on a
219    // GLConsumer that is not in the 'detached' state will result in an
220    // INVALID_OPERATION error.
221    //
222    // The tex argument specifies the OpenGL ES texture object name in the
223    // new context into which the image contents will be streamed.  A successful
224    // call to attachToContext will result in this texture object being bound to
225    // the texture target and populated with the image contents that were
226    // current at the time of the last call to detachFromContext.
227    status_t attachToContext(GLuint tex);
228
229protected:
230
231    // abandonLocked overrides the ConsumerBase method to clear
232    // mCurrentTextureBuf in addition to the ConsumerBase behavior.
233    virtual void abandonLocked();
234
235    // dumpLocked overrides the ConsumerBase method to dump GLConsumer-
236    // specific info in addition to the ConsumerBase behavior.
237    virtual void dumpLocked(String8& result, const char* prefix, char* buffer,
238           size_t size) const;
239
240    // acquireBufferLocked overrides the ConsumerBase method to update the
241    // mEglSlots array in addition to the ConsumerBase behavior.
242    virtual status_t acquireBufferLocked(BufferQueue::BufferItem *item);
243
244    // releaseBufferLocked overrides the ConsumerBase method to update the
245    // mEglSlots array in addition to the ConsumerBase.
246    virtual status_t releaseBufferLocked(int buf, EGLDisplay display,
247           EGLSyncKHR eglFence);
248
249    status_t releaseBufferLocked(int buf, EGLSyncKHR eglFence) {
250        return releaseBufferLocked(buf, 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 releaseAndUpdateLocked(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    status_t checkAndUpdateEglStateLocked();
270
271    // If set, GLConsumer will use the EGL_ANDROID_native_fence_sync
272    // extension to create Android native fences for GLES activity.
273    static const bool sUseNativeFenceSync;
274
275private:
276    // createImage creates a new EGLImage from a GraphicBuffer.
277    EGLImageKHR createImage(EGLDisplay dpy,
278            const sp<GraphicBuffer>& graphicBuffer);
279
280    // freeBufferLocked frees up the given buffer slot.  If the slot has been
281    // initialized this will release the reference to the GraphicBuffer in that
282    // slot and destroy the EGLImage in that slot.  Otherwise it has no effect.
283    //
284    // This method must be called with mMutex locked.
285    virtual void freeBufferLocked(int slotIndex);
286
287    // computeCurrentTransformMatrixLocked computes the transform matrix for the
288    // current texture.  It uses mCurrentTransform and the current GraphicBuffer
289    // to compute this matrix and stores it in mCurrentTransformMatrix.
290    // mCurrentTextureBuf must not be NULL.
291    void computeCurrentTransformMatrixLocked();
292
293    // doGLFenceWaitLocked inserts a wait command into the OpenGL ES command
294    // stream to ensure that it is safe for future OpenGL ES commands to
295    // access the current texture buffer.
296    status_t doGLFenceWaitLocked() const;
297
298    // syncForReleaseLocked performs the synchronization needed to release the
299    // current slot from an OpenGL ES context.  If needed it will set the
300    // current slot's fence to guard against a producer accessing the buffer
301    // before the outstanding accesses have completed.
302    status_t syncForReleaseLocked(EGLDisplay dpy);
303
304    // Normally, when we bind a buffer to a texture target, we bind a buffer
305    // that is referenced by an entry in mEglSlots.  In some situations we
306    // have a buffer in mCurrentTextureBuf, but no corresponding entry for
307    // it in our slot array.  bindUnslottedBuffer handles that situation by
308    // binding the buffer without touching the EglSlots.
309    status_t bindUnslottedBufferLocked(EGLDisplay dpy);
310
311    // The default consumer usage flags that GLConsumer always sets on its
312    // BufferQueue instance; these will be OR:d with any additional flags passed
313    // from the GLConsumer user. In particular, GLConsumer will always
314    // consume buffers as hardware textures.
315    static const uint32_t DEFAULT_USAGE_FLAGS = GraphicBuffer::USAGE_HW_TEXTURE;
316
317    // mCurrentTextureBuf is the graphic buffer of the current texture. It's
318    // possible that this buffer is not associated with any buffer slot, so we
319    // must track it separately in order to support the getCurrentBuffer method.
320    sp<GraphicBuffer> mCurrentTextureBuf;
321
322    // mCurrentCrop is the crop rectangle that applies to the current texture.
323    // It gets set each time updateTexImage is called.
324    Rect mCurrentCrop;
325
326    // mCurrentTransform is the transform identifier for the current texture. It
327    // gets set each time updateTexImage is called.
328    uint32_t mCurrentTransform;
329
330    // mCurrentScalingMode is the scaling mode for the current texture. It gets
331    // set to each time updateTexImage is called.
332    uint32_t mCurrentScalingMode;
333
334    // mCurrentFence is the fence received from BufferQueue in updateTexImage.
335    sp<Fence> mCurrentFence;
336
337    // mCurrentTransformMatrix is the transform matrix for the current texture.
338    // It gets computed by computeTransformMatrix each time updateTexImage is
339    // called.
340    float mCurrentTransformMatrix[16];
341
342    // mCurrentTimestamp is the timestamp for the current texture. It
343    // gets set each time updateTexImage is called.
344    int64_t mCurrentTimestamp;
345
346    uint32_t mDefaultWidth, mDefaultHeight;
347
348    // mFilteringEnabled indicates whether the transform matrix is computed for
349    // use with bilinear filtering. It defaults to true and is changed by
350    // setFilteringEnabled().
351    bool mFilteringEnabled;
352
353    // mTexName is the name of the OpenGL texture to which streamed images will
354    // be bound when updateTexImage is called. It is set at construction time
355    // and can be changed with a call to attachToContext.
356    GLuint mTexName;
357
358    // mUseFenceSync indicates whether creation of the EGL_KHR_fence_sync
359    // extension should be used to prevent buffers from being dequeued before
360    // it's safe for them to be written. It gets set at construction time and
361    // never changes.
362    const bool mUseFenceSync;
363
364    // mTexTarget is the GL texture target with which the GL texture object is
365    // associated.  It is set in the constructor and never changed.  It is
366    // almost always GL_TEXTURE_EXTERNAL_OES except for one use case in Android
367    // Browser.  In that case it is set to GL_TEXTURE_2D to allow
368    // glCopyTexSubImage to read from the texture.  This is a hack to work
369    // around a GL driver limitation on the number of FBO attachments, which the
370    // browser's tile cache exceeds.
371    const GLenum mTexTarget;
372
373    // EGLSlot contains the information and object references that
374    // GLConsumer maintains about a BufferQueue buffer slot.
375    struct EglSlot {
376        EglSlot()
377        : mEglImage(EGL_NO_IMAGE_KHR),
378          mEglFence(EGL_NO_SYNC_KHR) {
379        }
380
381        // mEglImage is the EGLImage created from mGraphicBuffer.
382        EGLImageKHR mEglImage;
383
384        // mFence is the EGL sync object that must signal before the buffer
385        // associated with this buffer slot may be dequeued. It is initialized
386        // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based
387        // on a compile-time option) set to a new sync object in updateTexImage.
388        EGLSyncKHR mEglFence;
389    };
390
391    // mEglDisplay is the EGLDisplay with which this GLConsumer is currently
392    // associated.  It is intialized to EGL_NO_DISPLAY and gets set to the
393    // current display when updateTexImage is called for the first time and when
394    // attachToContext is called.
395    EGLDisplay mEglDisplay;
396
397    // mEglContext is the OpenGL ES context with which this GLConsumer is
398    // currently associated.  It is initialized to EGL_NO_CONTEXT and gets set
399    // to the current GL context when updateTexImage is called for the first
400    // time and when attachToContext is called.
401    EGLContext mEglContext;
402
403    // mEGLSlots stores the buffers that have been allocated by the BufferQueue
404    // for each buffer slot.  It is initialized to null pointers, and gets
405    // filled in with the result of BufferQueue::acquire when the
406    // client dequeues a buffer from a
407    // slot that has not yet been used. The buffer allocated to a slot will also
408    // be replaced if the requested buffer usage or geometry differs from that
409    // of the buffer allocated to a slot.
410    EglSlot mEglSlots[BufferQueue::NUM_BUFFER_SLOTS];
411
412    // mCurrentTexture is the buffer slot index of the buffer that is currently
413    // bound to the OpenGL texture. It is initialized to INVALID_BUFFER_SLOT,
414    // indicating that no buffer slot is currently bound to the texture. Note,
415    // however, that a value of INVALID_BUFFER_SLOT does not necessarily mean
416    // that no buffer is bound to the texture. A call to setBufferCount will
417    // reset mCurrentTexture to INVALID_BUFFER_SLOT.
418    int mCurrentTexture;
419
420    // mAttached indicates whether the ConsumerBase is currently attached to
421    // an OpenGL ES context.  For legacy reasons, this is initialized to true,
422    // indicating that the ConsumerBase is considered to be attached to
423    // whatever context is current at the time of the first updateTexImage call.
424    // It is set to false by detachFromContext, and then set to true again by
425    // attachToContext.
426    bool mAttached;
427};
428
429// ----------------------------------------------------------------------------
430}; // namespace android
431
432#endif // ANDROID_GUI_CONSUMER_H
433