/* * Copyright (C) 2011 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. */ #ifndef HW_EMULATOR_CAMERA_EMULATED_CAMERA_DEVICE_H #define HW_EMULATOR_CAMERA_EMULATED_CAMERA_DEVICE_H /* * Contains declaration of an abstract class EmulatedCameraDevice that defines * functionality expected from an emulated physical camera device: * - Obtaining and setting camera device parameters * - Capturing frames * - Streaming video * - etc. */ #include #include #include #include "EmulatedCameraCommon.h" #include "Converters.h" namespace android { class EmulatedCamera; /* Encapsulates an abstract class EmulatedCameraDevice that defines * functionality expected from an emulated physical camera device: * - Obtaining and setting camera device parameters * - Capturing frames * - Streaming video * - etc. */ class EmulatedCameraDevice { public: /* Constructs EmulatedCameraDevice instance. * Param: * camera_hal - Emulated camera that implements the camera HAL API, and * manages (contains) this object. */ explicit EmulatedCameraDevice(EmulatedCamera* camera_hal); /* Destructs EmulatedCameraDevice instance. */ virtual ~EmulatedCameraDevice(); /*************************************************************************** * Emulated camera device abstract interface **************************************************************************/ public: /* Connects to the camera device. * This method must be called on an initialized instance of this class. * Return: * NO_ERROR on success, or an appropriate error status. */ virtual status_t connectDevice() = 0; /* Disconnects from the camera device. * Return: * NO_ERROR on success, or an appropriate error status. If this method is * called for already disconnected, or uninitialized instance of this class, * a successful status must be returned from this method. If this method is * called for an instance that is in the "started" state, this method must * return a failure. */ virtual status_t disconnectDevice() = 0; /* Starts the camera device. * This method tells the camera device to start capturing frames of the given * dimensions for the given pixel format. Note that this method doesn't start * the delivery of the captured frames to the emulated camera. Call * startDeliveringFrames method to start delivering frames. This method must * be called on a connected instance of this class. If it is called on a * disconnected instance, this method must return a failure. * Param: * width, height - Frame dimensions to use when capturing video frames. * pix_fmt - Pixel format to use when capturing video frames. * Return: * NO_ERROR on success, or an appropriate error status. */ virtual status_t startDevice(int width, int height, uint32_t pix_fmt) = 0; /* Stops the camera device. * This method tells the camera device to stop capturing frames. Note that * this method doesn't stop delivering frames to the emulated camera. Always * call stopDeliveringFrames prior to calling this method. * Return: * NO_ERROR on success, or an appropriate error status. If this method is * called for an object that is not capturing frames, or is disconnected, * or is uninitialized, a successful status must be returned from this * method. */ virtual status_t stopDevice() = 0; /*************************************************************************** * Emulated camera device public API **************************************************************************/ public: /* Initializes EmulatedCameraDevice instance. * Derived classes should override this method in order to cache static * properties of the physical device (list of supported pixel formats, frame * sizes, etc.) If this method is called on an already initialized instance, * it must return a successful status. * Return: * NO_ERROR on success, or an appropriate error status. */ virtual status_t Initialize(); /* Initializes the white balance modes parameters. * The parameters are passed by each individual derived camera API to * represent that different camera manufacturers may have different * preferences on the white balance parameters. Green channel in the RGB * color space is fixed to keep the luminance to be reasonably constant. * * Param: * mode the text describing the current white balance mode * r_scale the scale factor for the R channel in RGB space * b_scale the scale factor for the B channel in RGB space. */ void initializeWhiteBalanceModes(const char* mode, const float r_scale, const float b_scale); /* Starts delivering frames captured from the camera device. * This method will start the worker thread that would be pulling frames from * the camera device, and will deliver the pulled frames back to the emulated * camera via onNextFrameAvailable callback. This method must be called on a * connected instance of this class with a started camera device. If it is * called on a disconnected instance, or camera device has not been started, * this method must return a failure. * Param: * one_burst - Controls how many frames should be delivered. If this * parameter is 'true', only one captured frame will be delivered to the * emulated camera. If this parameter is 'false', frames will keep * coming until stopDeliveringFrames method is called. Typically, this * parameter is set to 'true' only in order to obtain a single frame * that will be used as a "picture" in takePicture method of the * emulated camera. * Return: * NO_ERROR on success, or an appropriate error status. */ virtual status_t startDeliveringFrames(bool one_burst); /* Stops delivering frames captured from the camera device. * This method will stop the worker thread started by startDeliveringFrames. * Return: * NO_ERROR on success, or an appropriate error status. */ virtual status_t stopDeliveringFrames(); /* Sets the exposure compensation for the camera device. */ void setExposureCompensation(const float ev); /* Sets the white balance mode for the device. */ void setWhiteBalanceMode(const char* mode); /* Gets current framebuffer, converted into preview frame format. * This method must be called on a connected instance of this class with a * started camera device. If it is called on a disconnected instance, or * camera device has not been started, this method must return a failure. * Note that this method should be called only after at least one frame has * been captured and delivered. Otherwise it will return garbage in the * preview frame buffer. Typically, this method shuld be called from * onNextFrameAvailable callback. * Param: * buffer - Buffer, large enough to contain the entire preview frame. * Return: * NO_ERROR on success, or an appropriate error status. */ virtual status_t getCurrentPreviewFrame(void* buffer); /* Gets width of the frame obtained from the physical device. * Return: * Width of the frame obtained from the physical device. Note that value * returned from this method is valid only in case if camera device has been * started. */ inline int getFrameWidth() const { ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__); return mFrameWidth; } /* Gets height of the frame obtained from the physical device. * Return: * Height of the frame obtained from the physical device. Note that value * returned from this method is valid only in case if camera device has been * started. */ inline int getFrameHeight() const { ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__); return mFrameHeight; } /* Gets byte size of the current frame buffer. * Return: * Byte size of the frame buffer. Note that value returned from this method * is valid only in case if camera device has been started. */ inline size_t getFrameBufferSize() const { ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__); return mFrameBufferSize; } /* Gets number of pixels in the current frame buffer. * Return: * Number of pixels in the frame buffer. Note that value returned from this * method is valid only in case if camera device has been started. */ inline int getPixelNum() const { ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__); return mTotalPixels; } /* Gets pixel format of the frame that camera device streams to this class. * Throughout camera framework, there are three different forms of pixel * format representation: * - Original format, as reported by the actual camera device. Values for * this format are declared in bionic/libc/kernel/common/linux/videodev2.h * - String representation as defined in CameraParameters::PIXEL_FORMAT_XXX * strings in frameworks/base/include/camera/CameraParameters.h * - HAL_PIXEL_FORMAT_XXX format, as defined in system/core/include/system/graphics.h * Since emulated camera device gets its data from the actual device, it gets * pixel format in the original form. And that's the pixel format * representation that will be returned from this method. HAL components will * need to translate value returned from this method to the appropriate form. * This method must be called only on started instance of this class, since * it's applicable only when camera device is ready to stream frames. * Param: * pix_fmt - Upon success contains the original pixel format. * Return: * Current framebuffer's pixel format. Note that value returned from this * method is valid only in case if camera device has been started. */ inline uint32_t getOriginalPixelFormat() const { ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__); return mPixelFormat; } /* * State checkers. */ inline bool isInitialized() const { /* Instance is initialized when the worker thread has been successfuly * created (but not necessarily started). */ return mWorkerThread.get() != NULL && mState != ECDS_CONSTRUCTED; } inline bool isConnected() const { /* Instance is connected when its status is either"connected", or * "started". */ return mState == ECDS_CONNECTED || mState == ECDS_STARTED; } inline bool isStarted() const { return mState == ECDS_STARTED; } /**************************************************************************** * Emulated camera device private API ***************************************************************************/ protected: /* Performs common validation and calculation of startDevice parameters. * Param: * width, height, pix_fmt - Parameters passed to the startDevice method. * Return: * NO_ERROR on success, or an appropriate error status. */ virtual status_t commonStartDevice(int width, int height, uint32_t pix_fmt); /* Performs common cleanup on stopDevice. * This method will undo what commonStartDevice had done. */ virtual void commonStopDevice(); /** Computes a luminance value after taking the exposure compensation. * value into account. * * Param: * inputY - The input luminance value. * Return: * The luminance value after adjusting the exposure compensation. */ inline uint8_t changeExposure(const uint8_t& inputY) const { return static_cast(clamp(static_cast(inputY) * mExposureCompensation)); } /** Computes the pixel value in YUV space after adjusting to the current * white balance mode. */ void changeWhiteBalance(uint8_t& y, uint8_t& u, uint8_t& v) const; /**************************************************************************** * Worker thread management. * Typicaly when emulated camera device starts capturing frames from the * actual device, it does that in a worker thread created in StartCapturing, * and terminated in StopCapturing. Since this is such a typical scenario, * it makes sence to encapsulate worker thread management in the base class * for all emulated camera devices. ***************************************************************************/ protected: /* Starts the worker thread. * Typically, worker thread is started from startDeliveringFrames method of * this class. * Param: * one_burst - Controls how many times thread loop should run. If this * parameter is 'true', thread routine will run only once If this * parameter is 'false', thread routine will run until stopWorkerThread * method is called. See startDeliveringFrames for more info. * Return: * NO_ERROR on success, or an appropriate error status. */ virtual status_t startWorkerThread(bool one_burst); /* Stops the worker thread. * Note that this method will always wait for the worker thread to terminate. * Typically, worker thread is started from stopDeliveringFrames method of * this class. * Return: * NO_ERROR on success, or an appropriate error status. */ virtual status_t stopWorkerThread(); /* Implementation of the worker thread routine. * In the default implementation of the worker thread routine we simply * return 'false' forcing the thread loop to exit, and the thread to * terminate. Derived class should override that method to provide there the * actual frame delivery. * Return: * true To continue thread loop (this method will be called again), or false * to exit the thread loop and to terminate the thread. */ virtual bool inWorkerThread(); /* Encapsulates a worker thread used by the emulated camera device. */ friend class WorkerThread; class WorkerThread : public Thread { /**************************************************************************** * Public API ***************************************************************************/ public: inline explicit WorkerThread(EmulatedCameraDevice* camera_dev) : Thread(true), // Callbacks may involve Java calls. mCameraDevice(camera_dev), mThreadControl(-1), mControlFD(-1) { } inline ~WorkerThread() { ALOGW_IF(mThreadControl >= 0 || mControlFD >= 0, "%s: Control FDs are opened in the destructor", __FUNCTION__); if (mThreadControl >= 0) { close(mThreadControl); } if (mControlFD >= 0) { close(mControlFD); } } /* Starts the thread * Param: * one_burst - Controls how many times thread loop should run. If * this parameter is 'true', thread routine will run only once * If this parameter is 'false', thread routine will run until * stopThread method is called. See startWorkerThread for more * info. * Return: * NO_ERROR on success, or an appropriate error status. */ inline status_t startThread(bool one_burst) { mOneBurst = one_burst; return run("Camera_startThread", ANDROID_PRIORITY_URGENT_DISPLAY, 0); } /* Overriden base class method. * It is overriden in order to provide one-time initialization just * prior to starting the thread routine. */ status_t readyToRun(); /* Stops the thread. */ status_t stopThread(); /* Values returned from the Select method of this class. */ enum SelectRes { /* A timeout has occurred. */ TIMEOUT, /* Data are available for read on the provided FD. */ READY, /* Thread exit request has been received. */ EXIT_THREAD, /* An error has occurred. */ ERROR }; /* Select on an FD event, keeping in mind thread exit message. * Param: * fd - File descriptor on which to wait for an event. This * parameter may be negative. If it is negative this method will * only wait on a control message to the thread. * timeout - Timeout in microseconds. 0 indicates no timeout (wait * forever). * Return: * See SelectRes enum comments. */ SelectRes Select(int fd, int timeout); /**************************************************************************** * Private API ***************************************************************************/ private: /* Implements abstract method of the base Thread class. */ bool threadLoop() { /* Simply dispatch the call to the containing camera device. */ if (mCameraDevice->inWorkerThread()) { /* Respect "one burst" parameter (see startThread). */ return !mOneBurst; } else { return false; } } /* Containing camera device object. */ EmulatedCameraDevice* mCameraDevice; /* FD that is used to send control messages into the thread. */ int mThreadControl; /* FD that thread uses to receive control messages. */ int mControlFD; /* Controls number of times the thread loop runs. * See startThread for more information. */ bool mOneBurst; /* Enumerates control messages that can be sent into the thread. */ enum ControlMessage { /* Stop the thread. */ THREAD_STOP }; Condition mSetup; }; /* Worker thread accessor. */ inline WorkerThread* getWorkerThread() const { return mWorkerThread.get(); } /**************************************************************************** * Data members ***************************************************************************/ protected: /* Locks this instance for parameters, state, etc. change. */ Mutex mObjectLock; /* Worker thread that is used in frame capturing. */ sp mWorkerThread; /* Timestamp of the current frame. */ nsecs_t mCurFrameTimestamp; /* Emulated camera object containing this instance. */ EmulatedCamera* mCameraHAL; /* Framebuffer containing the current frame. */ uint8_t* mCurrentFrame; /* * Framebuffer properties. */ /* Byte size of the framebuffer. */ size_t mFrameBufferSize; /* Original pixel format (one of the V4L2_PIX_FMT_XXX values, as defined in * bionic/libc/kernel/common/linux/videodev2.h */ uint32_t mPixelFormat; /* Frame width */ int mFrameWidth; /* Frame height */ int mFrameHeight; /* Total number of pixels */ int mTotalPixels; /* Exposure compensation value */ float mExposureCompensation; float* mWhiteBalanceScale; DefaultKeyedVector mSupportedWhiteBalanceScale; /* Defines possible states of the emulated camera device object. */ enum EmulatedCameraDeviceState { /* Object has been constructed. */ ECDS_CONSTRUCTED, /* Object has been initialized. */ ECDS_INITIALIZED, /* Object has been connected to the physical device. */ ECDS_CONNECTED, /* Camera device has been started. */ ECDS_STARTED, }; /* Object state. */ EmulatedCameraDeviceState mState; }; }; /* namespace android */ #endif /* HW_EMULATOR_CAMERA_EMULATED_CAMERA_DEVICE_H */