GLConsumer.h revision e692ab9a6be63193c5b52a6562d85d06c40463b8
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 that will signal when the current buffer
102    // is no longer being read. This fence will be returned to the producer
103    // when the current buffer is released by updateTexImage(). Multiple
104    // fences can be set for a given buffer; they will be merged into a single
105    // union fence.
106    void setReleaseFence(const sp<Fence>& fence);
107
108    // setDefaultMaxBufferCount sets the default limit on the maximum number
109    // of buffers that will be allocated at one time. The image producer may
110    // override the limit.
111    status_t setDefaultMaxBufferCount(int bufferCount);
112
113    // getTransformMatrix retrieves the 4x4 texture coordinate transform matrix
114    // associated with the texture image set by the most recent call to
115    // updateTexImage.
116    //
117    // This transform matrix maps 2D homogeneous texture coordinates of the form
118    // (s, t, 0, 1) with s and t in the inclusive range [0, 1] to the texture
119    // coordinate that should be used to sample that location from the texture.
120    // Sampling the texture outside of the range of this transform is undefined.
121    //
122    // This transform is necessary to compensate for transforms that the stream
123    // content producer may implicitly apply to the content. By forcing users of
124    // a GLConsumer to apply this transform we avoid performing an extra
125    // copy of the data that would be needed to hide the transform from the
126    // user.
127    //
128    // The matrix is stored in column-major order so that it may be passed
129    // directly to OpenGL ES via the glLoadMatrixf or glUniformMatrix4fv
130    // functions.
131    void getTransformMatrix(float mtx[16]);
132
133    // getTimestamp retrieves the timestamp associated with the texture image
134    // set by the most recent call to updateTexImage.
135    //
136    // The timestamp is in nanoseconds, and is monotonically increasing. Its
137    // other semantics (zero point, etc) are source-dependent and should be
138    // documented by the source.
139    int64_t getTimestamp();
140
141    // setDefaultBufferSize is used to set the size of buffers returned by
142    // requestBuffers when a with and height of zero is requested.
143    // A call to setDefaultBufferSize() may trigger requestBuffers() to
144    // be called from the client.
145    // The width and height parameters must be no greater than the minimum of
146    // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
147    // An error due to invalid dimensions might not be reported until
148    // updateTexImage() is called.
149    status_t setDefaultBufferSize(uint32_t width, uint32_t height);
150
151    // setFilteringEnabled sets whether the transform matrix should be computed
152    // for use with bilinear filtering.
153    void setFilteringEnabled(bool enabled);
154
155    // getCurrentBuffer returns the buffer associated with the current image.
156    sp<GraphicBuffer> getCurrentBuffer() const;
157
158    // getCurrentTextureTarget returns the texture target of the current
159    // texture as returned by updateTexImage().
160    GLenum getCurrentTextureTarget() const;
161
162    // getCurrentCrop returns the cropping rectangle of the current buffer.
163    Rect getCurrentCrop() const;
164
165    // getCurrentTransform returns the transform of the current buffer.
166    uint32_t getCurrentTransform() const;
167
168    // getCurrentScalingMode returns the scaling mode of the current buffer.
169    uint32_t getCurrentScalingMode() const;
170
171    // getCurrentFence returns the fence indicating when the current buffer is
172    // ready to be read from.
173    sp<Fence> getCurrentFence() const;
174
175    // doGLFenceWait inserts a wait command into the OpenGL ES command stream
176    // to ensure that it is safe for future OpenGL ES commands to access the
177    // current texture buffer.
178    status_t doGLFenceWait() const;
179
180    // isSynchronousMode returns whether the GLConsumer is currently in
181    // synchronous mode.
182    bool isSynchronousMode() const;
183
184    // set the name of the GLConsumer that will be used to identify it in
185    // log messages.
186    void setName(const String8& name);
187
188    // These functions call the corresponding BufferQueue implementation
189    // so the refactoring can proceed smoothly
190    status_t setDefaultBufferFormat(uint32_t defaultFormat);
191    status_t setConsumerUsageBits(uint32_t usage);
192    status_t setTransformHint(uint32_t hint);
193    virtual status_t setSynchronousMode(bool enabled);
194
195    // getBufferQueue returns the BufferQueue object to which this
196    // GLConsumer is connected.
197    sp<BufferQueue> getBufferQueue() const {
198        return mBufferQueue;
199    }
200
201    // detachFromContext detaches the GLConsumer from the calling thread's
202    // current OpenGL ES context.  This context must be the same as the context
203    // that was current for previous calls to updateTexImage.
204    //
205    // Detaching a GLConsumer from an OpenGL ES context will result in the
206    // deletion of the OpenGL ES texture object into which the images were being
207    // streamed.  After a GLConsumer has been detached from the OpenGL ES
208    // context calls to updateTexImage will fail returning INVALID_OPERATION
209    // until the GLConsumer is attached to a new OpenGL ES context using the
210    // attachToContext method.
211    status_t detachFromContext();
212
213    // attachToContext attaches a GLConsumer that is currently in the
214    // 'detached' state to the current OpenGL ES context.  A GLConsumer is
215    // in the 'detached' state iff detachFromContext has successfully been
216    // called and no calls to attachToContext have succeeded since the last
217    // detachFromContext call.  Calls to attachToContext made on a
218    // GLConsumer that is not in the 'detached' state will result in an
219    // INVALID_OPERATION error.
220    //
221    // The tex argument specifies the OpenGL ES texture object name in the
222    // new context into which the image contents will be streamed.  A successful
223    // call to attachToContext will result in this texture object being bound to
224    // the texture target and populated with the image contents that were
225    // current at the time of the last call to detachFromContext.
226    status_t attachToContext(GLuint tex);
227
228protected:
229
230    // abandonLocked overrides the ConsumerBase method to clear
231    // mCurrentTextureBuf in addition to the ConsumerBase behavior.
232    virtual void abandonLocked();
233
234    // dumpLocked overrides the ConsumerBase method to dump GLConsumer-
235    // specific info in addition to the ConsumerBase behavior.
236    virtual void dumpLocked(String8& result, const char* prefix, char* buffer,
237           size_t size) const;
238
239    // acquireBufferLocked overrides the ConsumerBase method to update the
240    // mEglSlots array in addition to the ConsumerBase behavior.
241    virtual status_t acquireBufferLocked(BufferQueue::BufferItem *item);
242
243    // releaseBufferLocked overrides the ConsumerBase method to update the
244    // mEglSlots array in addition to the ConsumerBase.
245    virtual status_t releaseBufferLocked(int buf, EGLDisplay display,
246           EGLSyncKHR eglFence);
247
248    status_t releaseBufferLocked(int buf, EGLSyncKHR eglFence) {
249        return releaseBufferLocked(buf, mEglDisplay, eglFence);
250    }
251
252    static bool isExternalFormat(uint32_t format);
253
254    // This releases the buffer in the slot referenced by mCurrentTexture,
255    // then updates state to refer to the BufferItem, which must be a
256    // newly-acquired buffer.
257    status_t releaseAndUpdateLocked(const BufferQueue::BufferItem& item);
258
259    // Binds mTexName and the current buffer to mTexTarget.  Uses
260    // mCurrentTexture if it's set, mCurrentTextureBuf if not.  If the
261    // bind succeeds, this calls doGLFenceWait.
262    status_t bindTextureImageLocked();
263
264    // Gets the current EGLDisplay and EGLContext values, and compares them
265    // to mEglDisplay and mEglContext.  If the fields have been previously
266    // set, the values must match; if not, the fields are set to the current
267    // values.
268    status_t checkAndUpdateEglStateLocked();
269
270private:
271    // createImage creates a new EGLImage from a GraphicBuffer.
272    EGLImageKHR createImage(EGLDisplay dpy,
273            const sp<GraphicBuffer>& graphicBuffer);
274
275    // freeBufferLocked frees up the given buffer slot.  If the slot has been
276    // initialized this will release the reference to the GraphicBuffer in that
277    // slot and destroy the EGLImage in that slot.  Otherwise it has no effect.
278    //
279    // This method must be called with mMutex locked.
280    virtual void freeBufferLocked(int slotIndex);
281
282    // computeCurrentTransformMatrixLocked computes the transform matrix for the
283    // current texture.  It uses mCurrentTransform and the current GraphicBuffer
284    // to compute this matrix and stores it in mCurrentTransformMatrix.
285    // mCurrentTextureBuf must not be NULL.
286    void computeCurrentTransformMatrixLocked();
287
288    // doGLFenceWaitLocked inserts a wait command into the OpenGL ES command
289    // stream to ensure that it is safe for future OpenGL ES commands to
290    // access the current texture buffer.
291    status_t doGLFenceWaitLocked() const;
292
293    // syncForReleaseLocked performs the synchronization needed to release the
294    // current slot from an OpenGL ES context.  If needed it will set the
295    // current slot's fence to guard against a producer accessing the buffer
296    // before the outstanding accesses have completed.
297    status_t syncForReleaseLocked(EGLDisplay dpy);
298
299    // Normally, when we bind a buffer to a texture target, we bind a buffer
300    // that is referenced by an entry in mEglSlots.  In some situations we
301    // have a buffer in mCurrentTextureBuf, but no corresponding entry for
302    // it in our slot array.  bindUnslottedBuffer handles that situation by
303    // binding the buffer without touching the EglSlots.
304    status_t bindUnslottedBufferLocked(EGLDisplay dpy);
305
306    // The default consumer usage flags that GLConsumer always sets on its
307    // BufferQueue instance; these will be OR:d with any additional flags passed
308    // from the GLConsumer user. In particular, GLConsumer will always
309    // consume buffers as hardware textures.
310    static const uint32_t DEFAULT_USAGE_FLAGS = GraphicBuffer::USAGE_HW_TEXTURE;
311
312    // mCurrentTextureBuf is the graphic buffer of the current texture. It's
313    // possible that this buffer is not associated with any buffer slot, so we
314    // must track it separately in order to support the getCurrentBuffer method.
315    sp<GraphicBuffer> mCurrentTextureBuf;
316
317    // mCurrentCrop is the crop rectangle that applies to the current texture.
318    // It gets set each time updateTexImage is called.
319    Rect mCurrentCrop;
320
321    // mCurrentTransform is the transform identifier for the current texture. It
322    // gets set each time updateTexImage is called.
323    uint32_t mCurrentTransform;
324
325    // mCurrentScalingMode is the scaling mode for the current texture. It gets
326    // set each time updateTexImage is called.
327    uint32_t mCurrentScalingMode;
328
329    // mCurrentFence is the fence received from BufferQueue in updateTexImage.
330    sp<Fence> mCurrentFence;
331
332    // mCurrentTransformMatrix is the transform matrix for the current texture.
333    // It gets computed by computeTransformMatrix each time updateTexImage is
334    // called.
335    float mCurrentTransformMatrix[16];
336
337    // mCurrentTimestamp is the timestamp for the current texture. It
338    // gets set each time updateTexImage is called.
339    int64_t mCurrentTimestamp;
340
341    uint32_t mDefaultWidth, mDefaultHeight;
342
343    // mFilteringEnabled indicates whether the transform matrix is computed for
344    // use with bilinear filtering. It defaults to true and is changed by
345    // setFilteringEnabled().
346    bool mFilteringEnabled;
347
348    // mTexName is the name of the OpenGL texture to which streamed images will
349    // be bound when updateTexImage is called. It is set at construction time
350    // and can be changed with a call to attachToContext.
351    GLuint mTexName;
352
353    // mUseFenceSync indicates whether creation of the EGL_KHR_fence_sync
354    // extension should be used to prevent buffers from being dequeued before
355    // it's safe for them to be written. It gets set at construction time and
356    // never changes.
357    const bool mUseFenceSync;
358
359    // mTexTarget is the GL texture target with which the GL texture object is
360    // associated.  It is set in the constructor and never changed.  It is
361    // almost always GL_TEXTURE_EXTERNAL_OES except for one use case in Android
362    // Browser.  In that case it is set to GL_TEXTURE_2D to allow
363    // glCopyTexSubImage to read from the texture.  This is a hack to work
364    // around a GL driver limitation on the number of FBO attachments, which the
365    // browser's tile cache exceeds.
366    const GLenum mTexTarget;
367
368    // EGLSlot contains the information and object references that
369    // GLConsumer maintains about a BufferQueue buffer slot.
370    struct EglSlot {
371        EglSlot()
372        : mEglImage(EGL_NO_IMAGE_KHR),
373          mEglFence(EGL_NO_SYNC_KHR) {
374        }
375
376        // mEglImage is the EGLImage created from mGraphicBuffer.
377        EGLImageKHR mEglImage;
378
379        // mFence is the EGL sync object that must signal before the buffer
380        // associated with this buffer slot may be dequeued. It is initialized
381        // to EGL_NO_SYNC_KHR when the buffer is created and (optionally, based
382        // on a compile-time option) set to a new sync object in updateTexImage.
383        EGLSyncKHR mEglFence;
384    };
385
386    // mEglDisplay is the EGLDisplay with which this GLConsumer is currently
387    // associated.  It is intialized to EGL_NO_DISPLAY and gets set to the
388    // current display when updateTexImage is called for the first time and when
389    // attachToContext is called.
390    EGLDisplay mEglDisplay;
391
392    // mEglContext is the OpenGL ES context with which this GLConsumer is
393    // currently associated.  It is initialized to EGL_NO_CONTEXT and gets set
394    // to the current GL context when updateTexImage is called for the first
395    // time and when attachToContext is called.
396    EGLContext mEglContext;
397
398    // mEGLSlots stores the buffers that have been allocated by the BufferQueue
399    // for each buffer slot.  It is initialized to null pointers, and gets
400    // filled in with the result of BufferQueue::acquire when the
401    // client dequeues a buffer from a
402    // slot that has not yet been used. The buffer allocated to a slot will also
403    // be replaced if the requested buffer usage or geometry differs from that
404    // of the buffer allocated to a slot.
405    EglSlot mEglSlots[BufferQueue::NUM_BUFFER_SLOTS];
406
407    // mCurrentTexture is the buffer slot index of the buffer that is currently
408    // bound to the OpenGL texture. It is initialized to INVALID_BUFFER_SLOT,
409    // indicating that no buffer slot is currently bound to the texture. Note,
410    // however, that a value of INVALID_BUFFER_SLOT does not necessarily mean
411    // that no buffer is bound to the texture. A call to setBufferCount will
412    // reset mCurrentTexture to INVALID_BUFFER_SLOT.
413    int mCurrentTexture;
414
415    // mAttached indicates whether the ConsumerBase is currently attached to
416    // an OpenGL ES context.  For legacy reasons, this is initialized to true,
417    // indicating that the ConsumerBase is considered to be attached to
418    // whatever context is current at the time of the first updateTexImage call.
419    // It is set to false by detachFromContext, and then set to true again by
420    // attachToContext.
421    bool mAttached;
422};
423
424// ----------------------------------------------------------------------------
425}; // namespace android
426
427#endif // ANDROID_GUI_CONSUMER_H
428