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1 /*
2  * Copyright 2019 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 #pragma once
18 
19 #include <android/hardware_buffer.h>
20 #include <gui/BufferQueueDefs.h>
21 #include <gui/ConsumerBase.h>
22 #include <gui/IGraphicBufferProducer.h>
23 #include <sys/cdefs.h>
24 #include <system/graphics.h>
25 #include <ui/FenceTime.h>
26 #include <ui/GraphicBuffer.h>
27 #include <utils/Mutex.h>
28 #include <utils/String8.h>
29 
30 #include "EGLConsumer.h"
31 #include "ImageConsumer.h"
32 
33 namespace android {
34 
35 /*
36  * SurfaceTexture consumes buffers of graphics data from a BufferQueue,
37  * and makes them available to HWUI render thread as a SkImage and to
38  * an application GL render thread as an OpenGL texture.
39  *
40  * When attached to an application GL render thread, a typical usage
41  * pattern is to set up the SurfaceTexture with the
42  * desired options, and call updateTexImage() when a new frame is desired.
43  * If a new frame is available, the texture will be updated.  If not,
44  * the previous contents are retained.
45  *
46  * When attached to a HWUI render thread, the TextureView implementation
47  * calls dequeueBuffer, which either pulls a new buffer or returns the
48  * last cached buffer if BufferQueue is empty.
49  * When attached to HWUI render thread, SurfaceTexture is compatible to
50  * both Vulkan and GL drawing pipelines.
51  */
52 class ANDROID_API SurfaceTexture : public ConsumerBase {
53 public:
54     /**
55      * Callback function needed by dequeueBuffer. It creates a fence,
56      * that is signalled, when the previous buffer is no longer in use by HWUI
57      * and can be used by written by the producer.
58      */
59     typedef status_t (*SurfaceTexture_createReleaseFence)(bool useFenceSync, EGLSyncKHR* eglFence,
60                                                           EGLDisplay* display, int* releaseFence,
61                                                           void* passThroughHandle);
62 
63     /**
64      * Callback function needed by dequeueBuffer. It waits for the new buffer
65      * fence to signal, before issuing any draw commands.
66      */
67     typedef status_t (*SurfaceTexture_fenceWait)(int fence, void* passThroughHandle);
68 
69     enum { TEXTURE_EXTERNAL = 0x8D65 }; // GL_TEXTURE_EXTERNAL_OES
70     typedef ConsumerBase::FrameAvailableListener FrameAvailableListener;
71 
72     /**
73      * SurfaceTexture constructs a new SurfaceTexture object. If the constructor
74      * with the tex parameter is used, tex indicates the name of the OpenGL ES
75      * texture to which images are to be streamed. texTarget specifies the
76      * OpenGL ES texture target to which the texture will be bound in
77      * updateTexImage. useFenceSync specifies whether fences should be used to
78      * synchronize access to buffers if that behavior is enabled at
79      * compile-time.
80      *
81      * A SurfaceTexture may be detached from one OpenGL ES context and then
82      * attached to a different context using the detachFromContext and
83      * attachToContext methods, respectively. The intention of these methods is
84      * purely to allow a SurfaceTexture to be transferred from one consumer
85      * context to another. If such a transfer is not needed there is no
86      * requirement that either of these methods be called.
87      *
88      * If the constructor with the tex parameter is used, the SurfaceTexture is
89      * created in a state where it is considered attached to an OpenGL ES
90      * context for the purposes of the attachToContext and detachFromContext
91      * methods. However, despite being considered "attached" to a context, the
92      * specific OpenGL ES context doesn't get latched until the first call to
93      * updateTexImage. After that point, all calls to updateTexImage must be
94      * made with the same OpenGL ES context current.
95      *
96      * If the constructor without the tex parameter is used, the SurfaceTexture
97      * is created in a detached state, and attachToContext must be called before
98      * calls to updateTexImage.
99      */
100     SurfaceTexture(const sp<IGraphicBufferConsumer>& bq, uint32_t tex, uint32_t textureTarget,
101                    bool useFenceSync, bool isControlledByApp);
102 
103     SurfaceTexture(const sp<IGraphicBufferConsumer>& bq, uint32_t textureTarget, bool useFenceSync,
104                    bool isControlledByApp);
105 
106     /**
107      * updateTexImage acquires the most recently queued buffer, and sets the
108      * image contents of the target texture to it.
109      *
110      * This call may only be made while the OpenGL ES context to which the
111      * target texture belongs is bound to the calling thread.
112      *
113      * This calls doGLFenceWait to ensure proper synchronization.
114      */
115     status_t updateTexImage();
116 
117     /**
118      * releaseTexImage releases the texture acquired in updateTexImage().
119      * This is intended to be used in single buffer mode.
120      *
121      * This call may only be made while the OpenGL ES context to which the
122      * target texture belongs is bound to the calling thread.
123      */
124     status_t releaseTexImage();
125 
126     /**
127      * getTransformMatrix retrieves the 4x4 texture coordinate transform matrix
128      * associated with the texture image set by the most recent call to
129      * updateTexImage.
130      *
131      * This transform matrix maps 2D homogeneous texture coordinates of the form
132      * (s, t, 0, 1) with s and t in the inclusive range [0, 1] to the texture
133      * coordinate that should be used to sample that location from the texture.
134      * Sampling the texture outside of the range of this transform is undefined.
135      *
136      * This transform is necessary to compensate for transforms that the stream
137      * content producer may implicitly apply to the content. By forcing users of
138      * a SurfaceTexture to apply this transform we avoid performing an extra
139      * copy of the data that would be needed to hide the transform from the
140      * user.
141      *
142      * The matrix is stored in column-major order so that it may be passed
143      * directly to OpenGL ES via the glLoadMatrixf or glUniformMatrix4fv
144      * functions.
145      */
146     void getTransformMatrix(float mtx[16]);
147 
148     /**
149      * Computes the transform matrix documented by getTransformMatrix
150      * from the BufferItem sub parts.
151      */
152     static void computeTransformMatrix(float outTransform[16], const sp<GraphicBuffer>& buf,
153                                        const Rect& cropRect, uint32_t transform, bool filtering);
154 
155     /**
156      * Scale the crop down horizontally or vertically such that it has the
157      * same aspect ratio as the buffer does.
158      */
159     static Rect scaleDownCrop(const Rect& crop, uint32_t bufferWidth, uint32_t bufferHeight);
160 
161     /**
162      * getTimestamp retrieves the timestamp associated with the texture image
163      * set by the most recent call to updateTexImage.
164      *
165      * The timestamp is in nanoseconds, and is monotonically increasing. Its
166      * other semantics (zero point, etc) are source-dependent and should be
167      * documented by the source.
168      */
169     int64_t getTimestamp();
170 
171     /**
172      * getDataSpace retrieves the DataSpace associated with the texture image
173      * set by the most recent call to updateTexImage.
174      */
175     android_dataspace getCurrentDataSpace();
176 
177     /**
178      * getFrameNumber retrieves the frame number associated with the texture
179      * image set by the most recent call to updateTexImage.
180      *
181      * The frame number is an incrementing counter set to 0 at the creation of
182      * the BufferQueue associated with this consumer.
183      */
184     uint64_t getFrameNumber();
185 
186     /**
187      * setDefaultBufferSize is used to set the size of buffers returned by
188      * requestBuffers when a with and height of zero is requested.
189      * A call to setDefaultBufferSize() may trigger requestBuffers() to
190      * be called from the client.
191      * The width and height parameters must be no greater than the minimum of
192      * GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
193      * An error due to invalid dimensions might not be reported until
194      * updateTexImage() is called.
195      */
196     status_t setDefaultBufferSize(uint32_t width, uint32_t height);
197 
198     /**
199      * setFilteringEnabled sets whether the transform matrix should be computed
200      * for use with bilinear filtering.
201      */
202     void setFilteringEnabled(bool enabled);
203 
204     /**
205      * getCurrentTextureTarget returns the texture target of the current
206      * texture as returned by updateTexImage().
207      */
208     uint32_t getCurrentTextureTarget() const;
209 
210     /**
211      * getCurrentCrop returns the cropping rectangle of the current buffer.
212      */
213     Rect getCurrentCrop() const;
214 
215     /**
216      * getCurrentTransform returns the transform of the current buffer.
217      */
218     uint32_t getCurrentTransform() const;
219 
220     /**
221      * getCurrentScalingMode returns the scaling mode of the current buffer.
222      */
223     uint32_t getCurrentScalingMode() const;
224 
225     /**
226      * getCurrentFence returns the fence indicating when the current buffer is
227      * ready to be read from.
228      */
229     sp<Fence> getCurrentFence() const;
230 
231     /**
232      * getCurrentFence returns the FenceTime indicating when the current
233      * buffer is ready to be read from.
234      */
235     std::shared_ptr<FenceTime> getCurrentFenceTime() const;
236 
237     /**
238      * setConsumerUsageBits overrides the ConsumerBase method to OR
239      * DEFAULT_USAGE_FLAGS to usage.
240      */
241     status_t setConsumerUsageBits(uint64_t usage);
242 
243     /**
244      * detachFromContext detaches the SurfaceTexture from the calling thread's
245      * current OpenGL ES context.  This context must be the same as the context
246      * that was current for previous calls to updateTexImage.
247      *
248      * Detaching a SurfaceTexture from an OpenGL ES context will result in the
249      * deletion of the OpenGL ES texture object into which the images were being
250      * streamed.  After a SurfaceTexture has been detached from the OpenGL ES
251      * context calls to updateTexImage will fail returning INVALID_OPERATION
252      * until the SurfaceTexture is attached to a new OpenGL ES context using the
253      * attachToContext method.
254      */
255     status_t detachFromContext();
256 
257     /**
258      * attachToContext attaches a SurfaceTexture that is currently in the
259      * 'detached' state to the current OpenGL ES context.  A SurfaceTexture is
260      * in the 'detached' state iff detachFromContext has successfully been
261      * called and no calls to attachToContext have succeeded since the last
262      * detachFromContext call.  Calls to attachToContext made on a
263      * SurfaceTexture that is not in the 'detached' state will result in an
264      * INVALID_OPERATION error.
265      *
266      * The tex argument specifies the OpenGL ES texture object name in the
267      * new context into which the image contents will be streamed.  A successful
268      * call to attachToContext will result in this texture object being bound to
269      * the texture target and populated with the image contents that were
270      * current at the time of the last call to detachFromContext.
271      */
272     status_t attachToContext(uint32_t tex);
273 
274     sp<GraphicBuffer> dequeueBuffer(int* outSlotid, android_dataspace* outDataspace,
275                                     HdrMetadata* outHdrMetadata, float* outTransformMatrix,
276                                     uint32_t* outTransform, bool* outQueueEmpty,
277                                     SurfaceTexture_createReleaseFence createFence,
278                                     SurfaceTexture_fenceWait fenceWait,
279                                     void* fencePassThroughHandle, ARect* currentCrop);
280 
281     /**
282      * takeConsumerOwnership attaches a SurfaceTexture that is currently in the
283      * 'detached' state to a consumer context (usually HWUI RenderThread).
284      */
285     void takeConsumerOwnership();
286 
287     /**
288      * releaseConsumerOwnership detaches a SurfaceTexture from a consumer
289      * context (usually HWUI RenderThread).
290      */
291     void releaseConsumerOwnership();
292 
293 protected:
294     /**
295      * abandonLocked overrides the ConsumerBase method to clear
296      * mCurrentTextureImage in addition to the ConsumerBase behavior.
297      */
298     virtual void abandonLocked();
299 
300     /**
301      * dumpLocked overrides the ConsumerBase method to dump SurfaceTexture-
302      * specific info in addition to the ConsumerBase behavior.
303      */
304     virtual void dumpLocked(String8& result, const char* prefix) const override;
305 
306     /**
307      * acquireBufferLocked overrides the ConsumerBase method to update the
308      * mEglSlots array in addition to the ConsumerBase behavior.
309      */
310     virtual status_t acquireBufferLocked(BufferItem* item, nsecs_t presentWhen,
311                                          uint64_t maxFrameNumber = 0) override;
312 
313     /**
314      * releaseBufferLocked overrides the ConsumerBase method to update the
315      * mEglSlots array in addition to the ConsumerBase.
316      */
317     virtual status_t releaseBufferLocked(int slot, const sp<GraphicBuffer> graphicBuffer,
318                                          EGLDisplay display, EGLSyncKHR eglFence) override;
319 
320     /**
321      * freeBufferLocked frees up the given buffer slot. If the slot has been
322      * initialized this will release the reference to the GraphicBuffer in that
323      * slot and destroy the EGLImage in that slot.  Otherwise it has no effect.
324      *
325      * This method must be called with mMutex locked.
326      */
327     virtual void freeBufferLocked(int slotIndex);
328 
329     /**
330      * computeCurrentTransformMatrixLocked computes the transform matrix for the
331      * current texture.  It uses mCurrentTransform and the current GraphicBuffer
332      * to compute this matrix and stores it in mCurrentTransformMatrix.
333      * mCurrentTextureImage must not be NULL.
334      */
335     void computeCurrentTransformMatrixLocked();
336 
337     /**
338      * The default consumer usage flags that SurfaceTexture always sets on its
339      * BufferQueue instance; these will be OR:d with any additional flags passed
340      * from the SurfaceTexture user. In particular, SurfaceTexture will always
341      * consume buffers as hardware textures.
342      */
343     static const uint64_t DEFAULT_USAGE_FLAGS = GraphicBuffer::USAGE_HW_TEXTURE;
344 
345     /**
346      * mCurrentCrop is the crop rectangle that applies to the current texture.
347      * It gets set each time updateTexImage is called.
348      */
349     Rect mCurrentCrop;
350 
351     /**
352      * mCurrentTransform is the transform identifier for the current texture. It
353      * gets set each time updateTexImage is called.
354      */
355     uint32_t mCurrentTransform;
356 
357     /**
358      * mCurrentScalingMode is the scaling mode for the current texture. It gets
359      * set each time updateTexImage is called.
360      */
361     uint32_t mCurrentScalingMode;
362 
363     /**
364      * mCurrentFence is the fence received from BufferQueue in updateTexImage.
365      */
366     sp<Fence> mCurrentFence;
367 
368     /**
369      * The FenceTime wrapper around mCurrentFence.
370      */
371     std::shared_ptr<FenceTime> mCurrentFenceTime{FenceTime::NO_FENCE};
372 
373     /**
374      * mCurrentTransformMatrix is the transform matrix for the current texture.
375      * It gets computed by computeTransformMatrix each time updateTexImage is
376      * called.
377      */
378     float mCurrentTransformMatrix[16];
379 
380     /**
381      * mCurrentTimestamp is the timestamp for the current texture. It
382      * gets set each time updateTexImage is called.
383      */
384     int64_t mCurrentTimestamp;
385 
386     /**
387      * mCurrentDataSpace is the dataspace for the current texture. It
388      * gets set each time updateTexImage is called.
389      */
390     android_dataspace mCurrentDataSpace;
391 
392     /**
393      * mCurrentFrameNumber is the frame counter for the current texture.
394      * It gets set each time updateTexImage is called.
395      */
396     uint64_t mCurrentFrameNumber;
397 
398     uint32_t mDefaultWidth, mDefaultHeight;
399 
400     /**
401      * mFilteringEnabled indicates whether the transform matrix is computed for
402      * use with bilinear filtering. It defaults to true and is changed by
403      * setFilteringEnabled().
404      */
405     bool mFilteringEnabled;
406 
407     /**
408      * mTexName is the name of the OpenGL texture to which streamed images will
409      * be bound when updateTexImage is called. It is set at construction time
410      * and can be changed with a call to attachToContext.
411      */
412     uint32_t mTexName;
413 
414     /**
415      * mUseFenceSync indicates whether creation of the EGL_KHR_fence_sync
416      * extension should be used to prevent buffers from being dequeued before
417      * it's safe for them to be written. It gets set at construction time and
418      * never changes.
419      */
420     const bool mUseFenceSync;
421 
422     /**
423      * mTexTarget is the GL texture target with which the GL texture object is
424      * associated.  It is set in the constructor and never changed.  It is
425      * almost always GL_TEXTURE_EXTERNAL_OES except for one use case in Android
426      * Browser.  In that case it is set to GL_TEXTURE_2D to allow
427      * glCopyTexSubImage to read from the texture.  This is a hack to work
428      * around a GL driver limitation on the number of FBO attachments, which the
429      * browser's tile cache exceeds.
430      */
431     const uint32_t mTexTarget;
432 
433     /**
434      * mCurrentTexture is the buffer slot index of the buffer that is currently
435      * bound to the OpenGL texture. It is initialized to INVALID_BUFFER_SLOT,
436      * indicating that no buffer slot is currently bound to the texture. Note,
437      * however, that a value of INVALID_BUFFER_SLOT does not necessarily mean
438      * that no buffer is bound to the texture. A call to setBufferCount will
439      * reset mCurrentTexture to INVALID_BUFFER_SLOT.
440      */
441     int mCurrentTexture;
442 
443     enum class OpMode { detached, attachedToConsumer, attachedToGL };
444     /**
445      * mOpMode indicates whether the SurfaceTexture is currently attached to
446      * an OpenGL ES context or the consumer context.  For legacy reasons, this
447      * is initialized to, "attachedToGL" indicating that the SurfaceTexture is
448      * considered to be attached to whatever GL context is current at the time
449      * of the first updateTexImage call.
450      * It is set to "detached" by detachFromContext, and then set to
451      * "attachedToGL" again by attachToContext.
452      * takeConsumerOwnership/releaseConsumerOwnership are used to attach/detach
453      * from a consumer context - usually HWUI RenderThread.
454      */
455     OpMode mOpMode;
456 
457     /**
458      * mEGLConsumer has SurfaceTexture logic used when attached to GL context.
459      */
460     EGLConsumer mEGLConsumer;
461 
462     /**
463      * mImageConsumer has SurfaceTexture logic used when attached to a consumer
464      * context (usually HWUI RenderThread).
465      */
466     ImageConsumer mImageConsumer;
467 
468     friend class ImageConsumer;
469     friend class EGLConsumer;
470 };
471 
472 // ----------------------------------------------------------------------------
473 } // namespace android
474