Camera2 教程 4：通過TEXTURE OES方式實現(xiàn)相機預覽

青橙相機

GLES11Ext.GL_TEXTURE_EXTERNAL_OES的用處是什么？
上一張實現(xiàn)相機預覽的每一幀的輸出格式是YUV的（YUV），那么這個擴展紋理的作用就是實現(xiàn)YUV格式到RGB的自動轉(zhuǎn)化，我們就不需要再為此寫YUV轉(zhuǎn)RGB的代碼了

1. 創(chuàng)建xml和Render

//xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.jdf.camera.ui.CameraV2GLSurfaceView
        android:id="@+id/glsurfaceView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

//Activity
   @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_camera2_oes);
        //獲取SurfaceView
        glSurfaceView = findViewById(R.id.glsurfaceView);
        //封裝相機操作
        mCameraLoader = new Camera2OESLoader(this);
        //主要是實例化Render，并綁定
        glSurfaceView.init(mCameraLoader, false, Camera2OESActivity.this);
        findViewById(R.id.saveImage).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ImageUtils.saveBitmap = true;
            }
        });
    }


//GlSurfaceView
public class CameraV2GLSurfaceView extends GLSurfaceView {
    public static final String TAG = "Filter_CameraV2GLSurfaceView";
    private JImageRender mCameraV2Renderer;

    public void init(Camera2OESLoader camera, boolean isPreviewStarted, Context context) {
        setEGLContextClientVersion(2);

        mCameraV2Renderer = new JImageRender(new JImageFilter(context));
        mCameraV2Renderer.init(this, camera, isPreviewStarted, context);

        setRenderer(mCameraV2Renderer);
    }

    public CameraV2GLSurfaceView(Context context, AttributeSet attributes) {
        super(context, attributes);
    }
}

2 開啟相機

在Activity的onResume中，判斷glSurfaceView加載完畢后，獲取相機相機傳感器方向，并且根據(jù)GlSurfaceView大小獲取合適的預覽大小

//Activity
    @Override
    protected void onResume() {
        super.onResume();
        boolean laidOut = ViewCompat.isLaidOut(glSurfaceView);
        boolean b = !glSurfaceView.isLayoutRequested();
        JLog.d(TAG, "onResume.....laidOut[%b],[%b]",laidOut,b);
        if (laidOut && b) {
            mCameraLoader.onResume(glSurfaceView.getWidth(), glSurfaceView.getHeight());
        } else {
            glSurfaceView.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
                @Override
                public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop,
                                           int oldRight, int oldBottom) {
                    JLog.d(TAG, "onResume.....onLayoutChange");
                    glSurfaceView.removeOnLayoutChangeListener(this);
                    mCameraLoader.onResume(glSurfaceView.getWidth(), glSurfaceView.getHeight());
                }
            });
        }
    }

Camera2OESLoader.java

    public void onResume(int width, int height) {
        JLog.d(TAG, "onResume[%d,%d]...", width, height);
        mViewWidth = width;
        mViewHeight = height;
        setUpCamera();
    }


    protected void setUpCamera() {
        try {
            //獲取屏幕方向，相機傳感器方向，和預覽大小
            setUpCameraOutputs();
            if (ActivityCompat.checkSelfPermission(mActivity, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
                JLog.e(TAG, "Dont have CAMERA permission");
                return;
            }
            mCameraManager.openCamera(mCameraId, mCameraDeviceCallback, mCameraHandler);
        } catch (CameraAccessException e) {
            JLog.e(TAG, "Opening camera (ID: " + mCameraId + ") failed.");
            e.printStackTrace();
        }
    }

mCameraHandler是根據(jù)Camera2OESLoader中HandlerThread創(chuàng)建的，因為后續(xù)我們需要再Render線程中啟動預覽，為了保證相機打開和啟動預覽在同一個線程，需要指定同一個Handler

相機啟動成功后，我們?nèi)ender中創(chuàng)建OES紋理id，SufaceTexture和啟動預覽

3 啟動預覽

  • JImageRender.onSurfaceCreated

創(chuàng)建OES 紋理id

   @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) {
        JLog.i(TAG, "onSurfaceCreated......");
        mOESTextureId = Utils.createOESTextureObject();
        mFilterEngine.ifNeedInit();

    }
  • JImageRender.onDrawFrame
    然后在onDrawFrame第一次調(diào)用時，完成SurfaceTexture初始化和預覽啟動
   @Override
    public void onDrawFrame(GL10 gl) {

        Long t1 = System.currentTimeMillis();
        if (mSurfaceTexture != null) {
            mSurfaceTexture.updateTexImage();
            mSurfaceTexture.getTransformMatrix(transformMatrix);
        }

        if (!bIsPreviewStarted) {
            bIsPreviewStarted = initSurfaceTexture();
            bIsPreviewStarted = true;
            return;
        }

        glClearColor(1.0f, 0.0f, 0.0f, 0.0f);

        mFilterEngine.onDraw(transformMatrix,mOESTextureId,glCubeBuffer,glTextureBuffer);

        long t2 = System.currentTimeMillis();
        long t = t2 - t1;
        Log.i(TAG, "onDrawFrame: time: " + t);
    }
  • JImageRender. initSurfaceTexture
  public boolean initSurfaceTexture() {
     
        mSurfaceTexture = new SurfaceTexture(mOESTextureId);
        mCameraLoaer.setPreviewTexture(mSurfaceTexture);
        mCameraLoaer.startPreview();
        return true;
    }
  • Camera2OESLoader.startPreview
 public void startPreview() {
       
        mSurfaceTexture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
        final Surface surface = new Surface(mSurfaceTexture);

        try {

            mCameraDevice.createCaptureSession(Arrays.asList( surface), new CameraCaptureSession.StateCallback() {
                @Override
                public void onConfigured(@NonNull CameraCaptureSession session) {
                    try {
                        CaptureRequest.Builder builder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
                        builder.addTarget(surface);
                        mCaptureRequest = builder.build();
                        mCameraCaptureSession = session;
                        mCameraCaptureSession.setRepeatingRequest(mCaptureRequest, null, mCameraHandler);
                    } catch (CameraAccessException e) {
                        e.printStackTrace();
                    }
                }

                @Override
                public void onConfigureFailed(@NonNull CameraCaptureSession session) {

                }
            }, mCameraHandler);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

4 繪制渲染

預覽啟動后成功后，會更新SurfaceTexture，并更新紋理數(shù)據(jù)對應的紋理舉證，然后將該SurfaceTexture對應的OES紋理ID傳遞到OPENGL進行繪制

    @Override
    public void onDrawFrame(GL10 gl) {

        Long t1 = System.currentTimeMillis();
        if (mSurfaceTexture != null) {
           //更新SurfaceTexture紋理內(nèi)容
            mSurfaceTexture.updateTexImage();
            mSurfaceTexture.getTransformMatrix(transformMatrix);
        }

        if (!bIsPreviewStarted) {
            bIsPreviewStarted = initSurfaceTexture();
            bIsPreviewStarted = true;
            return;
        }

        glClearColor(1.0f, 0.0f, 0.0f, 0.0f);
        //使用opengl繪制mOESTextureId對應的紋理內(nèi)容
        mFilterEngine.onDraw(transformMatrix, mOESTextureId,glCubeBuffer,glTextureBuffer)
  
    }

注意：
updateTexImage()方法只能在包OpenGLES環(huán)境的線程里調(diào)用，即Renderer接口所獨立創(chuàng)建的線程當中。一般在onDrawFrame中調(diào)用updateTexImage()將數(shù)據(jù)綁定給OpenGLES對應的紋理對象

JimageFilter.onDraw

  public void onDraw(float[] transformMatrix, int textureId, FloatBuffer cubeBuffer, FloatBuffer textureBuffer) {
      
        GLES30.glUseProgram(glProgId);
           ....
        if (textureId != OpenGlUtils.NO_TEXTURE) {
            ...
           glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, textureId);
           ...
           glUniformMatrix4fv(uTextureMatrixLocation, 1, false, transformMatrix, 0);
        }
         ...
        GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, 0);

    }

onDraw過程與上一節(jié)的相機預覽流程一致，主要差別有兩點

  1. 綁定和解綁紋理id的類型為GL_TEXTURE_EXTERNAL_OES
  2. 需要額外將從SurfaceTexture中產(chǎn)生的變換矩陣uTextureMatrixLocation傳遞到著色器中

5 定義OES著色器

因為紋理id使用的是OES格式，著色器中紋理類型也要對應修改，相對于上以上相機預覽實現(xiàn)，作色器主要有兩個變化

頂點著色器中，需要傳遞SurfaceTexture產(chǎn)生的變換矩陣對象uTextureMatrix，并根據(jù)矩陣值調(diào)整紋理坐標位置

attribute vec4 position;
uniform mat4 uTextureMatrix;
attribute vec4 inputTextureCoordinate;
varying vec2 textureCoordinate;
void main()
{
  textureCoordinate = (uTextureMatrix * inputTextureCoordinate).xy;
  gl_Position = position;
}`

片元著色器中，需要聲明紋理的類型為samplerExternalOES ，而不是sampler2D; 需要在文件頭聲明使用了samplerExternalOES，否則加載著色器會報錯

#extension GL_OES_EGL_image_external : require
precision mediump float;
uniform samplerExternalOES inputImageTexture;
varying vec2 textureCoordinate;
void main()
{
  gl_FragColor = texture2D(inputImageTexture, textureCoordinate);
}

6 顯示效果

預覽效果

7 流程總結(jié)

相機OES預覽.png

主要流程為：

  1. 定義GlSurfaceView和定義OEG紋理類型的著色器

  2. 將GlSurfaceView和Render,設(shè)置渲染模式

  3. 在GlSurfaceView加載完畢后，啟動相機

  4. 在Render的onSurfaceCreate中，完成OES紋理id創(chuàng)建和初始化Opengl對象

  5. 在相機開啟成功的時候，在onDrawFrame中完成預覽啟動；之所以在onDrawFrame啟動，是因為其他階段，相機不一定啟動成功

  6. 預覽啟動成功后，會在Render的每一幀調(diào)用時，更新SurfaceTexture的內(nèi)容，并更新對應的OES紋理id；將紋理id傳遞到opengl對象中進行渲染

  7. 渲染成功后，預覽數(shù)據(jù)會顯示到屏幕上

8 代碼位置

代碼具體實現(xiàn)參考 QCCamera中的JCamera2OESFboActivity

最后編輯于 ：
?著作權(quán)歸作者所有,轉(zhuǎn)載或內(nèi)容合作請聯(lián)系作者
【社區(qū)內(nèi)容提示】社區(qū)部分內(nèi)容疑似由AI輔助生成，瀏覽時請結(jié)合常識與多方信息審慎甄別。
平臺聲明：文章內(nèi)容（如有圖片或視頻亦包括在內(nèi)）由作者上傳并發(fā)布，文章內(nèi)容僅代表作者本人觀點，簡書系信息發(fā)布平臺，僅提供信息存儲服務。

相關(guān)閱讀更多精彩內(nèi)容

友情鏈接更多精彩內(nèi)容