一、Camera2的大致了解：
①凛剥、 CameraManager：作為整個(gè)框架的入口侠仇，用于初始化其他類；
②犁珠、CameraCharacteristics：通過(guò)CameraManager獲得逻炊，可提供Camera相關(guān)參數(shù)；
③犁享、CameraDevice：通過(guò)CameraManager獲得余素，類似之前的Camera類，可以進(jìn)行預(yù)覽等操作炊昆，例如：設(shè)置顯示預(yù)覽的Surface桨吊。
④、CaptureRequest.Builder：通過(guò)CameraDevice獲得凤巨，可以設(shè)置預(yù)覽的相關(guān)配置视乐。
⑤、CameraCaptureSession：通過(guò)CameraDevice獲得敢茁，控制通過(guò)CaptureRequest.Builder進(jìn)行預(yù)覽佑淀。
使用流程：
CameraManager -> CameraDevice -> CaptureRequest.Builder-> CameraCaptureSession
（原文鏈接：https://blog.csdn.net/ccw0054/article/details/80339208）
下面是對(duì)代碼的分析：
官方代碼：https://github.com/android/camera-samples
以下是一個(gè)demo的代碼：

private void openCamera(int width, int height) {
        if (ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.CAMERA)
                != PackageManager.PERMISSION_GRANTED) {
            requestCameraPermission();
            return;
        }
        setUpCameraOutputs(width, height);
        Log.d("PCC","setup test");
        Activity activity = getActivity();
        CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
        try {
            if (!mCameraOpenCloseLock.tryAcquire(2500, TimeUnit.MILLISECONDS)) {
                throw new RuntimeException("Time out waiting to lock camera opening.");
            }

            Log.d("111","cameraid"+mCameraId);
            manager.openCamera("0", mStateCallback, mBackgroundHandler);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            throw new RuntimeException("Interrupted while trying to lock camera opening.", e);
        }
    }
private void setUpCameraOutputs(int width, int height) {
        Activity activity = getActivity();
        CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
        try {
            for (String cameraId : manager.getCameraIdList()) {
                Log.d("PC1",cameraId);
                CameraCharacteristics characteristics
                        = manager.getCameraCharacteristics(cameraId);

                // We don't use a front facing camera in this sample.
                Integer facing = characteristics.get(CameraCharacteristics.LENS_FACING);
                if (facing != null && facing == CameraCharacteristics.LENS_FACING_FRONT) {
                    continue;
                }

                StreamConfigurationMap map = characteristics.get(
                        CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
                if (map == null) {
                    continue;
                }

                // For still image captures, we use the largest available size.
                Size largest = Collections.max(
                        Arrays.asList(map.getOutputSizes(ImageFormat.JPEG)),
                        new CompareSizesByArea());
                // Find out if we need to swap dimension to get the preview size relative to sensor
                // coordinate.
                int displayRotation = activity.getWindowManager().getDefaultDisplay().getRotation();
                //noinspection ConstantConditions
                mSensorOrientation = characteristics.get(CameraCharacteristics.SENSOR_ORIENTATION);
                boolean swappedDimensions = false;
                Log.d("PC3",cameraId);
                switch (displayRotation) {
                    case Surface.ROTATION_0:
                    case Surface.ROTATION_180:
                        if (mSensorOrientation == 90 || mSensorOrientation == 270) {
                            swappedDimensions = true;
                        }
                        break;
                    case Surface.ROTATION_90:
                    case Surface.ROTATION_270:
                        if (mSensorOrientation == 0 || mSensorOrientation == 180) {
                            swappedDimensions = true;
                        }
                        break;
                    default:
                        Log.e(TAG, "Display rotation is invalid: " + displayRotation);
                }
                Point displaySize = new Point();
                activity.getWindowManager().getDefaultDisplay().getSize(displaySize);
                int rotatedPreviewWidth = width;
                int rotatedPreviewHeight = height;
                int maxPreviewWidth = displaySize.x;
                int maxPreviewHeight = displaySize.y;

                if (swappedDimensions) {
                    rotatedPreviewWidth = height;
                    rotatedPreviewHeight = width;
                    maxPreviewWidth = displaySize.y;
                    maxPreviewHeight = displaySize.x;
                }

                if (maxPreviewWidth > MAX_PREVIEW_WIDTH) {
                    maxPreviewWidth = MAX_PREVIEW_WIDTH;
                }

                if (maxPreviewHeight > MAX_PREVIEW_HEIGHT) {
                    maxPreviewHeight = MAX_PREVIEW_HEIGHT;
                }
                // Danger, W.R.! Attempting to use too large a preview size could exceed the camera
                // bus' bandwidth limitation, resulting in gorgeous previews but the storage of
                // garbage capture data.
                mPreviewSize = chooseOptimalSize(map.getOutputSizes(SurfaceTexture.class),
                        rotatedPreviewWidth, rotatedPreviewHeight, maxPreviewWidth,
                        maxPreviewHeight, largest);
                // We fit the aspect ratio of TextureView to the size of preview we picked.
                int orientation = getResources().getConfiguration().orientation;
                if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
                    autoFitTextureView.setAspectRatio(
                            mPreviewSize.getWidth(), mPreviewSize.getHeight());
                } else {
                    autoFitTextureView.setAspectRatio(
                            mPreviewSize.getHeight(), mPreviewSize.getWidth());
                }
                // Check if the flash is supported.
                Boolean available = characteristics.get(CameraCharacteristics.FLASH_INFO_AVAILABLE);
                mFlashSupported = available == null ? false : available;
                mImageReader = ImageReader.newInstance(largest.getWidth(), largest.getHeight(),
                        ImageFormat.YUV_420_888, /*maxImages*/5);

                mCameraId = cameraId;
                return;
            }
        } catch (CameraAccessException e) {
            e.printStackTrace();
        } catch (NullPointerException e) {
            // Currently an NPE is thrown when the Camera2API is used but not supported on the
            // device this code runs.
            ErrorDialog.newInstance(getString(R.string.camera_error))
                    .show(getChildFragmentManager(), FRAGMENT_DIALOG);
        }
    }
private final CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {

        @Override
        public void onOpened(@NonNull CameraDevice cameraDevice) {
            // This method is called when the camera is opened. We start camera preview here.
            mCameraOpenCloseLock.release();
            mCameraDevice = cameraDevice;
            //createCameraPreviewSession();
        }

        @Override
        public void onDisconnected(@NonNull CameraDevice cameraDevice) {
            mCameraOpenCloseLock.release();
            cameraDevice.close();
            mCameraDevice = null;
        }

        @Override
        public void onError(@NonNull CameraDevice cameraDevice, int error) {
            mCameraOpenCloseLock.release();
            cameraDevice.close();
            mCameraDevice = null;
            Activity activity = getActivity();
            if (null != activity) {
                activity.finish();
            }
        }

    };
private void createCameraPreviewSession() {
        try {
            mSurfaceTexture.setDefaultBufferSize(MAX_PREVIEW_WIDTH, MAX_PREVIEW_HEIGHT);
            Surface surface = new Surface(mSurfaceTexture);
            // This is the output Surface we need to start preview.
            // We set up a CaptureRequest.Builder with the output Surface.
            mPreviewRequestBuilder
                    = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
            mPreviewRequestBuilder.addTarget(surface);
            //mPreviewRequestBuilder.addTarget(mImageReader.getSurface());

            // Here, we create a CameraCaptureSession for camera preview.
            mCameraDevice.createCaptureSession(Arrays.asList(surface, mImageReader.getSurface()),
                    new CameraCaptureSession.StateCallback() {

                        @Override
                        public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                            // The camera is already closed
                            if (null == mCameraDevice) {
                                return;
                            }
                            // When the session is ready, we start displaying the preview.
                            mCaptureSession = cameraCaptureSession;
                            // Auto focus should be continuous for camera preview.
                            mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE,
                                    CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
                            // Flash is automatically enabled when necessary.
                            setAutoFlash(mPreviewRequestBuilder);
                            // Finally, we start displaying the camera preview.
                            mPreviewRequest = mPreviewRequestBuilder.build();
                            try {
                                mCaptureSession.setRepeatingRequest(mPreviewRequest,
                                        null, mBackgroundHandler);
                            } catch (CameraAccessException e) {
                                e.printStackTrace();
                            }
                        }

                        @Override
                        public void onConfigureFailed(
                                @NonNull CameraCaptureSession cameraCaptureSession) {
                            showToast("Failed");
                        }
                    }, mBackgroundHandler
            );
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

代碼中我們可以看到openCamera這個(gè)函數(shù)首先會(huì)設(shè)置一個(gè)輸出的大小以使得我們camera得到的data不被拉伸以至于造成變形，然后會(huì) CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);獲取camera的服務(wù)以啟動(dòng)manager.openCamera("0", mStateCallback, mBackgroundHandler)彰檬，這里的mStateCallback就對(duì)應(yīng)device回調(diào)的一個(gè)狀態(tài)伸刃，也是camera2特有的一個(gè)特性，告訴我們攝像頭的狀態(tài)逢倍。camera open之后我們需要?jiǎng)?chuàng)建一個(gè)createCameraPreviewSession活動(dòng)奕枝，在這個(gè)函數(shù)我們創(chuàng)建的surfacetexture與紋理ID進(jìn)行綁定，同時(shí)與mPreviewRequestBuilder進(jìn)行通信瓶堕，使得我們可以正常顯示預(yù)覽數(shù)據(jù)隘道。
二、GLsurfaceview的大致了解：
GLsurfaceview作為surfaceview的補(bǔ)充，加入了EGL的管理（個(gè)人理解：極大的提供了一個(gè)接口谭梗，讓我們方便的使用Opengl ES）忘晤，一提到GLsurfaceview首先會(huì)想到render，在render中往往存在以下代碼：

 private GLSurfaceView.Renderer renderer=new GLSurfaceView.Renderer() {
        @Override
        public void onSurfaceCreated(GL10 gl10, EGLConfig eglConfig) {
          
       }
        @Override
        public void onSurfaceChanged(GL10 gl10, int width, int height) {
           
        }

        @Override
        public void onDrawFrame(GL10 gl10) {
          
        }
    };

render中分為onSurfaceCreated激捏、onSurfaceChanged和onDrawFrame三大塊设塔，onSurfaceCreated中我們常常會(huì)創(chuàng)建一個(gè)紋理坐標(biāo)和頂點(diǎn)坐標(biāo)，而紋理中我們會(huì)使用一個(gè)紋理ID去綁定我們的surfaceTexture远舅，這樣就可以將紋理加載到我們的view中闰蛔，而頂點(diǎn)坐標(biāo)常常是用來(lái)確定頂點(diǎn)的顏色，以及坐標(biāo)的對(duì)應(yīng)图柏。通過(guò)紋理我們可以獲取到一個(gè)對(duì)象序六，通過(guò)頂點(diǎn)我們可以將我們的對(duì)象按照不同需求繪制出來(lái)！在做預(yù)覽的時(shí)候蚤吹，首先需要打開(kāi)攝像頭例诀，也就是一中的 openCamera函數(shù)，接著我們會(huì)創(chuàng)建一個(gè)紋理對(duì)象（ID）裁着，創(chuàng)建好之后需要我們加載紋理坐標(biāo)和頂點(diǎn)坐標(biāo)繁涂，加載頂點(diǎn)時(shí)候，我們可以更改著色代碼二驰，對(duì)像素進(jìn)行操作扔罪，這些著色語(yǔ)言位于raw文件下，其中包含demo所寫的三種濾鏡的實(shí)現(xiàn)桶雀。
二值：

binary.png

edge.png

shared9.png