libs/hwui/surfacetexture/SurfaceTexture.h - LeafOS-Project/android_frameworks_base - Gitiles

 /*
  * Copyright (C) 2018 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #pragma once

 #include <gui/BufferQueueDefs.h>
 #include <gui/ConsumerBase.h>

 #include <ui/FenceTime.h>
 #include <ui/GraphicBuffer.h>

 #include <utils/Mutex.h>
 #include <utils/String8.h>

 #include "EGLConsumer.h"
 #include "ImageConsumer.h"

 namespace android {

 namespace uirenderer {
 class RenderState;
 }

 /*
  * SurfaceTexture consumes buffers of graphics data from a BufferQueue,
  * and makes them available to HWUI render thread as a SkImage and to
  * an application GL render thread as an OpenGL texture.
  *
  * When attached to an application GL render thread, a typical usage
  * pattern is to set up the SurfaceTexture with the
  * desired options, and call updateTexImage() when a new frame is desired.
  * If a new frame is available, the texture will be updated.  If not,
  * the previous contents are retained.
  *
  * When attached to a HWUI render thread, the TextureView implementation
  * calls dequeueImage, which either pulls a new SkImage or returns the
  * last cached SkImage if BufferQueue is empty.
  * When attached to HWUI render thread, SurfaceTexture is compatible to
  * both Vulkan and GL drawing pipelines.
  */
 class ANDROID_API SurfaceTexture : public ConsumerBase {
 public:
     enum { TEXTURE_EXTERNAL = 0x8D65 };  // GL_TEXTURE_EXTERNAL_OES
     typedef ConsumerBase::FrameAvailableListener FrameAvailableListener;

     /**
      * SurfaceTexture constructs a new SurfaceTexture object. If the constructor with
      * the tex parameter is used, tex indicates the name of the OpenGL ES
      * texture to which images are to be streamed. texTarget specifies the
      * OpenGL ES texture target to which the texture will be bound in
      * updateTexImage. useFenceSync specifies whether fences should be used to
      * synchronize access to buffers if that behavior is enabled at
      * compile-time.
      *
      * A SurfaceTexture may be detached from one OpenGL ES context and then
      * attached to a different context using the detachFromContext and
      * attachToContext methods, respectively. The intention of these methods is
      * purely to allow a SurfaceTexture to be transferred from one consumer
      * context to another. If such a transfer is not needed there is no
      * requirement that either of these methods be called.
      *
      * If the constructor with the tex parameter is used, the SurfaceTexture is
      * created in a state where it is considered attached to an OpenGL ES
      * context for the purposes of the attachToContext and detachFromContext
      * methods. However, despite being considered "attached" to a context, the
      * specific OpenGL ES context doesn't get latched until the first call to
      * updateTexImage. After that point, all calls to updateTexImage must be
      * made with the same OpenGL ES context current.
      *
      * If the constructor without the tex parameter is used, the SurfaceTexture is
      * created in a detached state, and attachToContext must be called before
      * calls to updateTexImage.
      */
     SurfaceTexture(const sp<IGraphicBufferConsumer>& bq, uint32_t tex, uint32_t texureTarget,
                    bool useFenceSync, bool isControlledByApp);

     SurfaceTexture(const sp<IGraphicBufferConsumer>& bq, uint32_t texureTarget, bool useFenceSync,
                    bool isControlledByApp);

     /**
      * updateTexImage acquires the most recently queued buffer, and sets the
      * image contents of the target texture to it.
      *
      * This call may only be made while the OpenGL ES context to which the
      * target texture belongs is bound to the calling thread.
      *
      * This calls doGLFenceWait to ensure proper synchronization.
      */
     status_t updateTexImage();

     /**
      * releaseTexImage releases the texture acquired in updateTexImage().
      * This is intended to be used in single buffer mode.
      *
      * This call may only be made while the OpenGL ES context to which the
      * target texture belongs is bound to the calling thread.
      */
     status_t releaseTexImage();

     /**
      * getTransformMatrix retrieves the 4x4 texture coordinate transform matrix
      * associated with the texture image set by the most recent call to
      * updateTexImage.
      *
      * This transform matrix maps 2D homogeneous texture coordinates of the form
      * (s, t, 0, 1) with s and t in the inclusive range [0, 1] to the texture
      * coordinate that should be used to sample that location from the texture.
      * Sampling the texture outside of the range of this transform is undefined.
      *
      * This transform is necessary to compensate for transforms that the stream
      * content producer may implicitly apply to the content. By forcing users of
      * a SurfaceTexture to apply this transform we avoid performing an extra
      * copy of the data that would be needed to hide the transform from the
      * user.
      *
      * The matrix is stored in column-major order so that it may be passed
      * directly to OpenGL ES via the glLoadMatrixf or glUniformMatrix4fv
      * functions.
      */
     void getTransformMatrix(float mtx[16]);

     /**
      * Computes the transform matrix documented by getTransformMatrix
      * from the BufferItem sub parts.
      */
     static void computeTransformMatrix(float outTransform[16], const sp<GraphicBuffer>& buf,
                                        const Rect& cropRect, uint32_t transform, bool filtering);

     /**
      * Scale the crop down horizontally or vertically such that it has the
      * same aspect ratio as the buffer does.
      */
     static Rect scaleDownCrop(const Rect& crop, uint32_t bufferWidth, uint32_t bufferHeight);

     /**
      * getTimestamp retrieves the timestamp associated with the texture image
      * set by the most recent call to updateTexImage.
      *
      * The timestamp is in nanoseconds, and is monotonically increasing. Its
      * other semantics (zero point, etc) are source-dependent and should be
      * documented by the source.
      */
     int64_t getTimestamp();

     /**
      * getDataSpace retrieves the DataSpace associated with the texture image
      * set by the most recent call to updateTexImage.
      */
     android_dataspace getCurrentDataSpace();

     /**
      * getFrameNumber retrieves the frame number associated with the texture
      * image set by the most recent call to updateTexImage.
      *
      * The frame number is an incrementing counter set to 0 at the creation of
      * the BufferQueue associated with this consumer.
      */
     uint64_t getFrameNumber();

     /**
      * setDefaultBufferSize is used to set the size of buffers returned by
      * requestBuffers when a with and height of zero is requested.
      * A call to setDefaultBufferSize() may trigger requestBuffers() to
      * be called from the client.
      * The width and height parameters must be no greater than the minimum of
      * GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
      * An error due to invalid dimensions might not be reported until
      * updateTexImage() is called.
      */
     status_t setDefaultBufferSize(uint32_t width, uint32_t height);

     /**
      * setFilteringEnabled sets whether the transform matrix should be computed
      * for use with bilinear filtering.
      */
     void setFilteringEnabled(bool enabled);

     /**
      * getCurrentTextureTarget returns the texture target of the current
      * texture as returned by updateTexImage().
      */
     uint32_t getCurrentTextureTarget() const;

     /**
      * getCurrentCrop returns the cropping rectangle of the current buffer.
      */
     Rect getCurrentCrop() const;

     /**
      * getCurrentTransform returns the transform of the current buffer.
      */
     uint32_t getCurrentTransform() const;

     /**
      * getCurrentScalingMode returns the scaling mode of the current buffer.
      */
     uint32_t getCurrentScalingMode() const;

     /**
      * getCurrentFence returns the fence indicating when the current buffer is
      * ready to be read from.
      */
     sp<Fence> getCurrentFence() const;

     /**
      * getCurrentFence returns the FenceTime indicating when the current
      * buffer is ready to be read from.
      */
     std::shared_ptr<FenceTime> getCurrentFenceTime() const;

     /**
      * setConsumerUsageBits overrides the ConsumerBase method to OR
      * DEFAULT_USAGE_FLAGS to usage.
      */
     status_t setConsumerUsageBits(uint64_t usage);

     /**
      * detachFromContext detaches the SurfaceTexture from the calling thread's
      * current OpenGL ES context.  This context must be the same as the context
      * that was current for previous calls to updateTexImage.
      *
      * Detaching a SurfaceTexture from an OpenGL ES context will result in the
      * deletion of the OpenGL ES texture object into which the images were being
      * streamed.  After a SurfaceTexture has been detached from the OpenGL ES
      * context calls to updateTexImage will fail returning INVALID_OPERATION
      * until the SurfaceTexture is attached to a new OpenGL ES context using the
      * attachToContext method.
      */
     status_t detachFromContext();

     /**
      * attachToContext attaches a SurfaceTexture that is currently in the
      * 'detached' state to the current OpenGL ES context.  A SurfaceTexture is
      * in the 'detached' state iff detachFromContext has successfully been
      * called and no calls to attachToContext have succeeded since the last
      * detachFromContext call.  Calls to attachToContext made on a
      * SurfaceTexture that is not in the 'detached' state will result in an
      * INVALID_OPERATION error.
      *
      * The tex argument specifies the OpenGL ES texture object name in the
      * new context into which the image contents will be streamed.  A successful
      * call to attachToContext will result in this texture object being bound to
      * the texture target and populated with the image contents that were
      * current at the time of the last call to detachFromContext.
      */
     status_t attachToContext(uint32_t tex);

     sk_sp<SkImage> dequeueImage(SkMatrix& transformMatrix, android_dataspace& dataSpace,
                                 bool* queueEmpty, uirenderer::RenderState& renderState);

     /**
      * attachToView attaches a SurfaceTexture that is currently in the
      * 'detached' state to HWUI View system.
      */
     void attachToView();

     /**
      * detachFromView detaches a SurfaceTexture from HWUI View system.
      */
     void detachFromView();

 protected:
     /**
      * abandonLocked overrides the ConsumerBase method to clear
      * mCurrentTextureImage in addition to the ConsumerBase behavior.
      */
     virtual void abandonLocked();

     /**
      * dumpLocked overrides the ConsumerBase method to dump SurfaceTexture-
      * specific info in addition to the ConsumerBase behavior.
      */
     virtual void dumpLocked(String8& result, const char* prefix) const override;

     /**
      * acquireBufferLocked overrides the ConsumerBase method to update the
      * mEglSlots array in addition to the ConsumerBase behavior.
      */
     virtual status_t acquireBufferLocked(BufferItem* item, nsecs_t presentWhen,
                                          uint64_t maxFrameNumber = 0) override;

     /**
      * releaseBufferLocked overrides the ConsumerBase method to update the
      * mEglSlots array in addition to the ConsumerBase.
      */
     virtual status_t releaseBufferLocked(int slot, const sp<GraphicBuffer> graphicBuffer,
                                          EGLDisplay display, EGLSyncKHR eglFence) override;

     /**
      * freeBufferLocked frees up the given buffer slot. If the slot has been
      * initialized this will release the reference to the GraphicBuffer in that
      * slot and destroy the EGLImage in that slot.  Otherwise it has no effect.
      *
      * This method must be called with mMutex locked.
      */
     virtual void freeBufferLocked(int slotIndex);

     /**
      * computeCurrentTransformMatrixLocked computes the transform matrix for the
      * current texture.  It uses mCurrentTransform and the current GraphicBuffer
      * to compute this matrix and stores it in mCurrentTransformMatrix.
      * mCurrentTextureImage must not be NULL.
      */
     void computeCurrentTransformMatrixLocked();

     /**
      * The default consumer usage flags that SurfaceTexture always sets on its
      * BufferQueue instance; these will be OR:d with any additional flags passed
      * from the SurfaceTexture user. In particular, SurfaceTexture will always
      * consume buffers as hardware textures.
      */
     static const uint64_t DEFAULT_USAGE_FLAGS = GraphicBuffer::USAGE_HW_TEXTURE;

     /**
      * mCurrentCrop is the crop rectangle that applies to the current texture.
      * It gets set each time updateTexImage is called.
      */
     Rect mCurrentCrop;

     /**
      * mCurrentTransform is the transform identifier for the current texture. It
      * gets set each time updateTexImage is called.
      */
     uint32_t mCurrentTransform;

     /**
      * mCurrentScalingMode is the scaling mode for the current texture. It gets
      * set each time updateTexImage is called.
      */
     uint32_t mCurrentScalingMode;

     /**
      * mCurrentFence is the fence received from BufferQueue in updateTexImage.
      */
     sp<Fence> mCurrentFence;

     /**
      * The FenceTime wrapper around mCurrentFence.
      */
     std::shared_ptr<FenceTime> mCurrentFenceTime{FenceTime::NO_FENCE};

     /**
      * mCurrentTransformMatrix is the transform matrix for the current texture.
      * It gets computed by computeTransformMatrix each time updateTexImage is
      * called.
      */
     float mCurrentTransformMatrix[16];

     /**
      * mCurrentTimestamp is the timestamp for the current texture. It
      * gets set each time updateTexImage is called.
      */
     int64_t mCurrentTimestamp;

     /**
      * mCurrentDataSpace is the dataspace for the current texture. It
      * gets set each time updateTexImage is called.
      */
     android_dataspace mCurrentDataSpace;

     /**
      * mCurrentFrameNumber is the frame counter for the current texture.
      * It gets set each time updateTexImage is called.
      */
     uint64_t mCurrentFrameNumber;

     uint32_t mDefaultWidth, mDefaultHeight;

     /**
      * mFilteringEnabled indicates whether the transform matrix is computed for
      * use with bilinear filtering. It defaults to true and is changed by
      * setFilteringEnabled().
      */
     bool mFilteringEnabled;

     /**
      * mTexName is the name of the OpenGL texture to which streamed images will
      * be bound when updateTexImage is called. It is set at construction time
      * and can be changed with a call to attachToContext.
      */
     uint32_t mTexName;

     /**
      * mUseFenceSync indicates whether creation of the EGL_KHR_fence_sync
      * extension should be used to prevent buffers from being dequeued before
      * it's safe for them to be written. It gets set at construction time and
      * never changes.
      */
     const bool mUseFenceSync;

     /**
      * mTexTarget is the GL texture target with which the GL texture object is
      * associated.  It is set in the constructor and never changed.  It is
      * almost always GL_TEXTURE_EXTERNAL_OES except for one use case in Android
      * Browser.  In that case it is set to GL_TEXTURE_2D to allow
      * glCopyTexSubImage to read from the texture.  This is a hack to work
      * around a GL driver limitation on the number of FBO attachments, which the
      * browser's tile cache exceeds.
      */
     const uint32_t mTexTarget;

     /**
      * mCurrentTexture is the buffer slot index of the buffer that is currently
      * bound to the OpenGL texture. It is initialized to INVALID_BUFFER_SLOT,
      * indicating that no buffer slot is currently bound to the texture. Note,
      * however, that a value of INVALID_BUFFER_SLOT does not necessarily mean
      * that no buffer is bound to the texture. A call to setBufferCount will
      * reset mCurrentTexture to INVALID_BUFFER_SLOT.
      */
     int mCurrentTexture;

     enum class OpMode { detached, attachedToView, attachedToGL };
     /**
      * mOpMode indicates whether the SurfaceTexture is currently attached to
      * an OpenGL ES context or the HWUI view system.  For legacy reasons, this is initialized to,
      * "attachedToGL" indicating that the SurfaceTexture is considered to be attached to
      * whatever GL context is current at the time of the first updateTexImage call.
      * It is set to "detached" by detachFromContext, and then set to "attachedToGL" again by
      * attachToContext.
      * attachToView/detachFromView are used to attach/detach from HWUI view system.
      */
     OpMode mOpMode;

     /**
      * mEGLConsumer has SurfaceTexture logic used when attached to GL context.
      */
     EGLConsumer mEGLConsumer;

     /**
      * mImageConsumer has SurfaceTexture logic used when attached to HWUI view system.
      */
     ImageConsumer mImageConsumer;

     friend class ImageConsumer;
     friend class EGLConsumer;
 };

 // ----------------------------------------------------------------------------
 };  // namespace android
	/*
	* Copyright (C) 2018 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#pragma once

	#include <gui/BufferQueueDefs.h>
	#include <gui/ConsumerBase.h>

	#include <ui/FenceTime.h>
	#include <ui/GraphicBuffer.h>

	#include <utils/Mutex.h>
	#include <utils/String8.h>

	#include "EGLConsumer.h"
	#include "ImageConsumer.h"

	namespace android {

	namespace uirenderer {
	class RenderState;
	}

	/*
	* SurfaceTexture consumes buffers of graphics data from a BufferQueue,
	* and makes them available to HWUI render thread as a SkImage and to
	* an application GL render thread as an OpenGL texture.
	*
	* When attached to an application GL render thread, a typical usage
	* pattern is to set up the SurfaceTexture with the
	* desired options, and call updateTexImage() when a new frame is desired.
	* If a new frame is available, the texture will be updated. If not,
	* the previous contents are retained.
	*
	* When attached to a HWUI render thread, the TextureView implementation
	* calls dequeueImage, which either pulls a new SkImage or returns the
	* last cached SkImage if BufferQueue is empty.
	* When attached to HWUI render thread, SurfaceTexture is compatible to
	* both Vulkan and GL drawing pipelines.
	*/
	class ANDROID_API SurfaceTexture : public ConsumerBase {
	public:
	enum { TEXTURE_EXTERNAL = 0x8D65 }; // GL_TEXTURE_EXTERNAL_OES
	typedef ConsumerBase::FrameAvailableListener FrameAvailableListener;

	/**
	* SurfaceTexture constructs a new SurfaceTexture object. If the constructor with
	* the tex parameter is used, tex indicates the name of the OpenGL ES
	* texture to which images are to be streamed. texTarget specifies the
	* OpenGL ES texture target to which the texture will be bound in
	* updateTexImage. useFenceSync specifies whether fences should be used to
	* synchronize access to buffers if that behavior is enabled at
	* compile-time.
	*
	* A SurfaceTexture may be detached from one OpenGL ES context and then
	* attached to a different context using the detachFromContext and
	* attachToContext methods, respectively. The intention of these methods is
	* purely to allow a SurfaceTexture to be transferred from one consumer
	* context to another. If such a transfer is not needed there is no
	* requirement that either of these methods be called.
	*
	* If the constructor with the tex parameter is used, the SurfaceTexture is
	* created in a state where it is considered attached to an OpenGL ES
	* context for the purposes of the attachToContext and detachFromContext
	* methods. However, despite being considered "attached" to a context, the
	* specific OpenGL ES context doesn't get latched until the first call to
	* updateTexImage. After that point, all calls to updateTexImage must be
	* made with the same OpenGL ES context current.
	*
	* If the constructor without the tex parameter is used, the SurfaceTexture is
	* created in a detached state, and attachToContext must be called before
	* calls to updateTexImage.
	*/
	SurfaceTexture(const sp<IGraphicBufferConsumer>& bq, uint32_t tex, uint32_t texureTarget,
	bool useFenceSync, bool isControlledByApp);

	SurfaceTexture(const sp<IGraphicBufferConsumer>& bq, uint32_t texureTarget, bool useFenceSync,
	bool isControlledByApp);

	/**
	* updateTexImage acquires the most recently queued buffer, and sets the
	* image contents of the target texture to it.
	*
	* This call may only be made while the OpenGL ES context to which the
	* target texture belongs is bound to the calling thread.
	*
	* This calls doGLFenceWait to ensure proper synchronization.
	*/
	status_t updateTexImage();

	/**
	* releaseTexImage releases the texture acquired in updateTexImage().
	* This is intended to be used in single buffer mode.
	*
	* This call may only be made while the OpenGL ES context to which the
	* target texture belongs is bound to the calling thread.
	*/
	status_t releaseTexImage();

	/**
	* getTransformMatrix retrieves the 4x4 texture coordinate transform matrix
	* associated with the texture image set by the most recent call to
	* updateTexImage.
	*
	* This transform matrix maps 2D homogeneous texture coordinates of the form
	* (s, t, 0, 1) with s and t in the inclusive range [0, 1] to the texture
	* coordinate that should be used to sample that location from the texture.
	* Sampling the texture outside of the range of this transform is undefined.
	*
	* This transform is necessary to compensate for transforms that the stream
	* content producer may implicitly apply to the content. By forcing users of
	* a SurfaceTexture to apply this transform we avoid performing an extra
	* copy of the data that would be needed to hide the transform from the
	* user.
	*
	* The matrix is stored in column-major order so that it may be passed
	* directly to OpenGL ES via the glLoadMatrixf or glUniformMatrix4fv
	* functions.
	*/
	void getTransformMatrix(float mtx[16]);

	/**
	* Computes the transform matrix documented by getTransformMatrix
	* from the BufferItem sub parts.
	*/
	static void computeTransformMatrix(float outTransform[16], const sp<GraphicBuffer>& buf,
	const Rect& cropRect, uint32_t transform, bool filtering);

	/**
	* Scale the crop down horizontally or vertically such that it has the
	* same aspect ratio as the buffer does.
	*/
	static Rect scaleDownCrop(const Rect& crop, uint32_t bufferWidth, uint32_t bufferHeight);

	/**
	* getTimestamp retrieves the timestamp associated with the texture image
	* set by the most recent call to updateTexImage.
	*
	* The timestamp is in nanoseconds, and is monotonically increasing. Its
	* other semantics (zero point, etc) are source-dependent and should be
	* documented by the source.
	*/
	int64_t getTimestamp();

	/**
	* getDataSpace retrieves the DataSpace associated with the texture image
	* set by the most recent call to updateTexImage.
	*/
	android_dataspace getCurrentDataSpace();

	/**
	* getFrameNumber retrieves the frame number associated with the texture
	* image set by the most recent call to updateTexImage.
	*
	* The frame number is an incrementing counter set to 0 at the creation of
	* the BufferQueue associated with this consumer.
	*/
	uint64_t getFrameNumber();

	/**
	* setDefaultBufferSize is used to set the size of buffers returned by
	* requestBuffers when a with and height of zero is requested.
	* A call to setDefaultBufferSize() may trigger requestBuffers() to
	* be called from the client.
	* The width and height parameters must be no greater than the minimum of
	* GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
	* An error due to invalid dimensions might not be reported until
	* updateTexImage() is called.
	*/
	status_t setDefaultBufferSize(uint32_t width, uint32_t height);

	/**
	* setFilteringEnabled sets whether the transform matrix should be computed
	* for use with bilinear filtering.
	*/
	void setFilteringEnabled(bool enabled);

	/**
	* getCurrentTextureTarget returns the texture target of the current
	* texture as returned by updateTexImage().
	*/
	uint32_t getCurrentTextureTarget() const;

	/**
	* getCurrentCrop returns the cropping rectangle of the current buffer.
	*/
	Rect getCurrentCrop() const;

	/**
	* getCurrentTransform returns the transform of the current buffer.
	*/
	uint32_t getCurrentTransform() const;

	/**
	* getCurrentScalingMode returns the scaling mode of the current buffer.
	*/
	uint32_t getCurrentScalingMode() const;

	/**
	* getCurrentFence returns the fence indicating when the current buffer is
	* ready to be read from.
	*/
	sp<Fence> getCurrentFence() const;

	/**
	* getCurrentFence returns the FenceTime indicating when the current
	* buffer is ready to be read from.
	*/
	std::shared_ptr<FenceTime> getCurrentFenceTime() const;

	/**
	* setConsumerUsageBits overrides the ConsumerBase method to OR
	* DEFAULT_USAGE_FLAGS to usage.
	*/
	status_t setConsumerUsageBits(uint64_t usage);

	/**
	* detachFromContext detaches the SurfaceTexture from the calling thread's
	* current OpenGL ES context. This context must be the same as the context
	* that was current for previous calls to updateTexImage.
	*
	* Detaching a SurfaceTexture from an OpenGL ES context will result in the
	* deletion of the OpenGL ES texture object into which the images were being
	* streamed. After a SurfaceTexture has been detached from the OpenGL ES
	* context calls to updateTexImage will fail returning INVALID_OPERATION
	* until the SurfaceTexture is attached to a new OpenGL ES context using the
	* attachToContext method.
	*/
	status_t detachFromContext();

	/**
	* attachToContext attaches a SurfaceTexture that is currently in the
	* 'detached' state to the current OpenGL ES context. A SurfaceTexture is
	* in the 'detached' state iff detachFromContext has successfully been
	* called and no calls to attachToContext have succeeded since the last
	* detachFromContext call. Calls to attachToContext made on a
	* SurfaceTexture that is not in the 'detached' state will result in an
	* INVALID_OPERATION error.
	*
	* The tex argument specifies the OpenGL ES texture object name in the
	* new context into which the image contents will be streamed. A successful
	* call to attachToContext will result in this texture object being bound to
	* the texture target and populated with the image contents that were
	* current at the time of the last call to detachFromContext.
	*/
	status_t attachToContext(uint32_t tex);

	sk_sp<SkImage> dequeueImage(SkMatrix& transformMatrix, android_dataspace& dataSpace,
	bool* queueEmpty, uirenderer::RenderState& renderState);

	/**
	* attachToView attaches a SurfaceTexture that is currently in the
	* 'detached' state to HWUI View system.
	*/
	void attachToView();

	/**
	* detachFromView detaches a SurfaceTexture from HWUI View system.
	*/
	void detachFromView();

	protected:
	/**
	* abandonLocked overrides the ConsumerBase method to clear
	* mCurrentTextureImage in addition to the ConsumerBase behavior.
	*/
	virtual void abandonLocked();

	/**
	* dumpLocked overrides the ConsumerBase method to dump SurfaceTexture-
	* specific info in addition to the ConsumerBase behavior.
	*/
	virtual void dumpLocked(String8& result, const char* prefix) const override;

	/**
	* acquireBufferLocked overrides the ConsumerBase method to update the
	* mEglSlots array in addition to the ConsumerBase behavior.
	*/
	virtual status_t acquireBufferLocked(BufferItem* item, nsecs_t presentWhen,
	uint64_t maxFrameNumber = 0) override;

	/**
	* releaseBufferLocked overrides the ConsumerBase method to update the
	* mEglSlots array in addition to the ConsumerBase.
	*/
	virtual status_t releaseBufferLocked(int slot, const sp<GraphicBuffer> graphicBuffer,
	EGLDisplay display, EGLSyncKHR eglFence) override;

	/**
	* freeBufferLocked frees up the given buffer slot. If the slot has been
	* initialized this will release the reference to the GraphicBuffer in that
	* slot and destroy the EGLImage in that slot. Otherwise it has no effect.
	*
	* This method must be called with mMutex locked.
	*/
	virtual void freeBufferLocked(int slotIndex);

	/**
	* computeCurrentTransformMatrixLocked computes the transform matrix for the
	* current texture. It uses mCurrentTransform and the current GraphicBuffer
	* to compute this matrix and stores it in mCurrentTransformMatrix.
	* mCurrentTextureImage must not be NULL.
	*/
	void computeCurrentTransformMatrixLocked();

	/**
	* The default consumer usage flags that SurfaceTexture always sets on its
	* BufferQueue instance; these will be OR:d with any additional flags passed
	* from the SurfaceTexture user. In particular, SurfaceTexture will always
	* consume buffers as hardware textures.
	*/
	static const uint64_t DEFAULT_USAGE_FLAGS = GraphicBuffer::USAGE_HW_TEXTURE;

	/**
	* mCurrentCrop is the crop rectangle that applies to the current texture.
	* It gets set each time updateTexImage is called.
	*/
	Rect mCurrentCrop;

	/**
	* mCurrentTransform is the transform identifier for the current texture. It
	* gets set each time updateTexImage is called.
	*/
	uint32_t mCurrentTransform;

	/**
	* mCurrentScalingMode is the scaling mode for the current texture. It gets
	* set each time updateTexImage is called.
	*/
	uint32_t mCurrentScalingMode;

	/**
	* mCurrentFence is the fence received from BufferQueue in updateTexImage.
	*/
	sp<Fence> mCurrentFence;

	/**
	* The FenceTime wrapper around mCurrentFence.
	*/
	std::shared_ptr<FenceTime> mCurrentFenceTime{FenceTime::NO_FENCE};

	/**
	* mCurrentTransformMatrix is the transform matrix for the current texture.
	* It gets computed by computeTransformMatrix each time updateTexImage is
	* called.
	*/
	float mCurrentTransformMatrix[16];

	/**
	* mCurrentTimestamp is the timestamp for the current texture. It
	* gets set each time updateTexImage is called.
	*/
	int64_t mCurrentTimestamp;

	/**
	* mCurrentDataSpace is the dataspace for the current texture. It
	* gets set each time updateTexImage is called.
	*/
	android_dataspace mCurrentDataSpace;

	/**
	* mCurrentFrameNumber is the frame counter for the current texture.
	* It gets set each time updateTexImage is called.
	*/
	uint64_t mCurrentFrameNumber;

	uint32_t mDefaultWidth, mDefaultHeight;

	/**
	* mFilteringEnabled indicates whether the transform matrix is computed for
	* use with bilinear filtering. It defaults to true and is changed by
	* setFilteringEnabled().
	*/
	bool mFilteringEnabled;

	/**
	* mTexName is the name of the OpenGL texture to which streamed images will
	* be bound when updateTexImage is called. It is set at construction time
	* and can be changed with a call to attachToContext.
	*/
	uint32_t mTexName;

	/**
	* mUseFenceSync indicates whether creation of the EGL_KHR_fence_sync
	* extension should be used to prevent buffers from being dequeued before
	* it's safe for them to be written. It gets set at construction time and
	* never changes.
	*/
	const bool mUseFenceSync;

	/**
	* mTexTarget is the GL texture target with which the GL texture object is
	* associated. It is set in the constructor and never changed. It is
	* almost always GL_TEXTURE_EXTERNAL_OES except for one use case in Android
	* Browser. In that case it is set to GL_TEXTURE_2D to allow
	* glCopyTexSubImage to read from the texture. This is a hack to work
	* around a GL driver limitation on the number of FBO attachments, which the
	* browser's tile cache exceeds.
	*/
	const uint32_t mTexTarget;

	/**
	* mCurrentTexture is the buffer slot index of the buffer that is currently
	* bound to the OpenGL texture. It is initialized to INVALID_BUFFER_SLOT,
	* indicating that no buffer slot is currently bound to the texture. Note,
	* however, that a value of INVALID_BUFFER_SLOT does not necessarily mean
	* that no buffer is bound to the texture. A call to setBufferCount will
	* reset mCurrentTexture to INVALID_BUFFER_SLOT.
	*/
	int mCurrentTexture;

	enum class OpMode { detached, attachedToView, attachedToGL };
	/**
	* mOpMode indicates whether the SurfaceTexture is currently attached to
	* an OpenGL ES context or the HWUI view system. For legacy reasons, this is initialized to,
	* "attachedToGL" indicating that the SurfaceTexture is considered to be attached to
	* whatever GL context is current at the time of the first updateTexImage call.
	* It is set to "detached" by detachFromContext, and then set to "attachedToGL" again by
	* attachToContext.
	* attachToView/detachFromView are used to attach/detach from HWUI view system.
	*/
	OpMode mOpMode;

	/**
	* mEGLConsumer has SurfaceTexture logic used when attached to GL context.
	*/
	EGLConsumer mEGLConsumer;

	/**
	* mImageConsumer has SurfaceTexture logic used when attached to HWUI view system.
	*/
	ImageConsumer mImageConsumer;

	friend class ImageConsumer;
	friend class EGLConsumer;
	};

	// ----------------------------------------------------------------------------
	}; // namespace android