Android使用Opengl錄像時添加(動態)水印

最近需要開發一個類似行車記錄儀的app，其中需要給錄製的視頻添加動態水印。我使用的是OpenGL開發的，剛開始實現的是靜態水印，後面才實現的動態水印。

先上效果圖，左下角的是靜態水印，中間偏下的是時間水印（動態水印）：

一、靜態水印
實現原理：錄像時是通過OpenGL把圖像渲染到GLSurfaceView上的，通俗的講，就是把圖片畫到一塊畫布上，然後展示出來。添加圖片水印，就是把水印圖片跟錄製的圖像一起畫到畫布上。

這是加載紋理跟陰影的Java類

package com.audiovideo.camera.blog;


import android.opengl.GLES20;


/**
 * Created by fenghaitao on 2019/9/12.
 */

public class WaterSignSProgram{

    private static int programId;
    private static final String VERTEX_SHADER =
                    "uniform mat4 uMVPMatrix;\n" +
                    "attribute vec4 aPosition;\n" +
                    "attribute vec4 aTextureCoord;\n" +
                    "varying vec2 vTextureCoord;\n" +
                    "void main() {\n" +
                    "    gl_Position = uMVPMatrix * aPosition;\n" +
                    "    vTextureCoord = aTextureCoord.xy;\n" +
                    "}\n";

    private static final String FRAGMENT_SHADER =
                    "precision mediump float;\n" +
                    "varying vec2 vTextureCoord;\n" +
                    "uniform sampler2D sTexture;\n" +
                    "void main() {\n" +
                    "    gl_FragColor = texture2D(sTexture, vTextureCoord);\n" +
                    "}\n";

    public WaterSignSProgram() {
        programId = loadShader(VERTEX_SHADER, FRAGMENT_SHADER);

        uMVPMatrixLoc = GLES20.glGetUniformLocation(programId, "uMVPMatrix");
        checkLocation(uMVPMatrixLoc, "uMVPMatrix");
        aPositionLoc = GLES20.glGetAttribLocation(programId, "aPosition");
        checkLocation(aPositionLoc, "aPosition");
        aTextureCoordLoc = GLES20.glGetAttribLocation(programId, "aTextureCoord");
        checkLocation(aTextureCoordLoc, "aTextureCoord");
        sTextureLoc = GLES20.glGetUniformLocation(programId, "sTexture");
        checkLocation(sTextureLoc, "sTexture");
    }

    public int uMVPMatrixLoc;
    public int aPositionLoc;
    public int aTextureCoordLoc;
    public int sTextureLoc;

    public static void checkLocation(int location, String label) {
        if (location < 0) {
            throw new RuntimeException("Unable to locate '" + label + "' in program");
        }
    }

/**
 * 加載編譯連接陰影
 * @param vss source of vertex shader
 * @param fss source of fragment shader
 * @return
 */
public static int loadShader(final String vss, final String fss) {
   Log.v(TAG, "loadShader:");
   int vs = GLES20.glCreateShader(GLES20.GL_VERTEX_SHADER);
   GLES20.glShaderSource(vs, vss);
   GLES20.glCompileShader(vs);
   final int[] compiled = new int[1];
   GLES20.glGetShaderiv(vs, GLES20.GL_COMPILE_STATUS, compiled, 0);
   if (compiled[0] == 0) {
      Log.e(TAG, "Failed to compile vertex shader:"
            + GLES20.glGetShaderInfoLog(vs));
      GLES20.glDeleteShader(vs);
      vs = 0;
   }

   int fs = GLES20.glCreateShader(GLES20.GL_FRAGMENT_SHADER);
   GLES20.glShaderSource(fs, fss);
   GLES20.glCompileShader(fs);
   GLES20.glGetShaderiv(fs, GLES20.GL_COMPILE_STATUS, compiled, 0);
   if (compiled[0] == 0) {
      Log.w(TAG, "Failed to compile fragment shader:"
         + GLES20.glGetShaderInfoLog(fs));
      GLES20.glDeleteShader(fs);
      fs = 0;
   }

   final int program = GLES20.glCreateProgram();
   GLES20.glAttachShader(program, vs);
   GLES20.glAttachShader(program, fs);
   GLES20.glLinkProgram(program);

   return program;
}

    /**
     * terminatinng, this should be called in GL context
     */
    public static void release() {
        if (programId >= 0)
            GLES20.glDeleteProgram(programId);
        programId = -1;
    }
}

package com.audiovideo.camera.blog;

import android.opengl.GLES20;
import android.opengl.Matrix;

import com.audiovideo.camera.glutils.GLDrawer2D;
import com.audiovideo.camera.utils.LogUtil;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;


這是畫水印的Java類
/**
 * Created by fenghaitao on 2019/9/12.
 */

public class WaterSignature {

    private static final String VERTEX_SHADER =
            "uniform mat4 uMVPMatrix;\n" +
                    "attribute vec4 aPosition;\n" +
                    "attribute vec4 aTextureCoord;\n" +
                    "varying vec2 vTextureCoord;\n" +
                    "void main() {\n" +
                    "    gl_Position = uMVPMatrix * aPosition;\n" +
                    "    vTextureCoord = aTextureCoord.xy;\n" +
                    "}\n";

    private static final String FRAGMENT_SHADER =
            "precision mediump float;\n" +
                    "varying vec2 vTextureCoord;\n" +
                    "uniform sampler2D sTexture;\n" +
                    "void main() {\n" +
                    "    gl_FragColor = texture2D(sTexture, vTextureCoord);\n" +
                    "}\n";

    public static final int SIZE_OF_FLOAT = 4;
    /**
     * 一個“完整”的正方形，從兩維延伸到-1到1。
     * 當 模型/視圖/投影矩陣是都爲單位矩陣的時候，這將完全覆蓋視口。
     * 紋理座標相對於矩形是y反的。
     * (This seems to work out right with external textures from SurfaceTexture.)
     */
    private static final float FULL_RECTANGLE_COORDS[] = {
            -1.0f, -1.0f,   // 0 bottom left
            1.0f, -1.0f,   // 1 bottom right
            -1.0f,  1.0f,   // 2 top left
            1.0f,  1.0f,   // 3 top right
    };
    private static final float FULL_RECTANGLE_TEX_COORDS[] = {
            0.0f, 1.0f,     //0 bottom left     //0.0f, 0.0f, // 0 bottom left
            1.0f, 1.0f,     //1 bottom right    //1.0f, 0.0f, // 1 bottom right
            0.0f, 0.0f,     //2 top left        //0.0f, 1.0f, // 2 top left
            1.0f, 0.0f,     //3 top right       //1.0f, 1.0f, // 3 top right
    };

    private FloatBuffer mVertexArray;
    private FloatBuffer mTexCoordArray;
    private int mCoordsPerVertex;
    private int mCoordsPerTexture;
    private int mVertexCount;
    private int mVertexStride;
    private int mTexCoordStride;
    private int hProgram;

    public float[] mProjectionMatrix = new float[16];// 投影矩陣
    public float[] mViewMatrix = new float[16]; // 攝像機位置朝向9參數矩陣
    public float[] mModelMatrix = new float[16];// 模型變換矩陣
    public float[] mMVPMatrix = new float[16];// 獲取具體物體的總變換矩陣
    private float[] getFinalMatrix() {
        Matrix.multiplyMM(mMVPMatrix, 0, mViewMatrix, 0, mModelMatrix, 0);
        Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mMVPMatrix, 0);
        return mMVPMatrix;
    }

    public WaterSignature() {
        mVertexArray = createFloatBuffer(FULL_RECTANGLE_COORDS);
        mTexCoordArray = createFloatBuffer(FULL_RECTANGLE_TEX_COORDS);
        mCoordsPerVertex = 2;
        mCoordsPerTexture = 2;
        mVertexCount = FULL_RECTANGLE_COORDS.length / mCoordsPerVertex; // 4
        mTexCoordStride = 2 * SIZE_OF_FLOAT;
        mVertexStride = 2 * SIZE_OF_FLOAT;

        Matrix.setIdentityM(mProjectionMatrix, 0);
        Matrix.setIdentityM(mViewMatrix, 0);
        Matrix.setIdentityM(mModelMatrix, 0);
        Matrix.setIdentityM(mMVPMatrix, 0);
        hProgram = GLDrawer2D.loadShader(VERTEX_SHADER, FRAGMENT_SHADER);
        GLES20.glUseProgram(hProgram);
    }

    private FloatBuffer createFloatBuffer(float[] coords) {
        ByteBuffer bb = ByteBuffer.allocateDirect(coords.length * SIZE_OF_FLOAT);
        bb.order(ByteOrder.nativeOrder());
        FloatBuffer fb = bb.asFloatBuffer();
        fb.put(coords);
        fb.position(0);
        return fb;
    }

    private WaterSignSProgram mProgram;

    public void setShaderProgram(WaterSignSProgram mProgram) {
        this.mProgram = mProgram;
    }

    public void drawFrame(int mTextureId) {
        GLES20.glUseProgram(hProgram);
        // 設置紋理
        GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mTextureId);
        GLES20.glUniform1i(mProgram.sTextureLoc, 0);
        GlUtil.checkGlError("GL_TEXTURE_2D sTexture");
        // 設置 model / view / projection 矩陣
        GLES20.glUniformMatrix4fv(mProgram.uMVPMatrixLoc, 1, false, getFinalMatrix(), 0);
        GlUtil.checkGlError("glUniformMatrix4fv uMVPMatrixLoc");
        // 使用簡單的VAO 設置頂點座標數據
        GLES20.glEnableVertexAttribArray(mProgram.aPositionLoc);
        GLES20.glVertexAttribPointer(mProgram.aPositionLoc, mCoordsPerVertex,
                GLES20.GL_FLOAT, false, mVertexStride, mVertexArray);
        GlUtil.checkGlError("VAO aPositionLoc");
        // 使用簡單的VAO 設置紋理座標數據
        GLES20.glEnableVertexAttribArray(mProgram.aTextureCoordLoc);
        GLES20.glVertexAttribPointer(mProgram.aTextureCoordLoc, mCoordsPerTexture,
                GLES20.GL_FLOAT, false, mTexCoordStride, mTexCoordArray);
        GlUtil.checkGlError("VAO aTextureCoordLoc");
        // GL_TRIANGLE_STRIP三角形帶，這就爲啥只需要指出4個座標點，就能畫出兩個三角形了。
        GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, mVertexCount);
        // Done -- 解綁~
        GLES20.glDisableVertexAttribArray(mProgram.aPositionLoc);
        GLES20.glDisableVertexAttribArray(mProgram.aTextureCoordLoc);
        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 0);
        GLES20.glUseProgram(0);
    }

    /**
     * terminatinng, this should be called in GL context
     */
    public void release() {
        if (hProgram >= 0)
            GLES20.glDeleteProgram(hProgram);
        hProgram = -1;
    }

    /**
     * 刪除texture
     */
    public static void deleteTex(final int hTex) {
        LogUtil.v("WaterSignature", "deleteTex:");
        final int[] tex = new int[] {hTex};
        GLES20.glDeleteTextures(1, tex, 0);
    }

}

沒時間了。先寫到這，後面是調用，遲點再寫。

下面是如何把水印繪製到畫布上：
1、在SurfaceTexture的onSurfaceCreated方法中初始化並設置陰影；

      @Override
      public void onSurfaceCreated(final GL10 unused, final EGLConfig config) {
         LogUtil.v(TAG, "onSurfaceCreated:");
         // This renderer required OES_EGL_image_external extension
         final String extensions = GLES20.glGetString(GLES20.GL_EXTENSIONS);    // API >= 8
      // 使用黃色清除界面
         GLES20.glClearColor(1.0f, 1.0f, 0.0f, 1.0f);
         //設置水印
            if (mWaterSign == null) {
                mWaterSign = new WaterSignature();
            }
            //設置陰影
         mWaterSign.setShaderProgram(new WaterSignSProgram());
        mSignTexId = loadTexture(MyApplication.getContext(), R.mipmap.watermark);
      }

這裏是生成mSignTexId 的方法，把該圖像與紋理id綁定並返回：

public static int loadTexture(Context context, int resourceId) {
    final int[] textureObjectIds = new int[1];
    GLES20.glGenTextures(1, textureObjectIds, 0);
    if(textureObjectIds[0] == 0){
        Log.e(TAG,"Could not generate a new OpenGL texture object!");
        return 0;
    }
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inScaled = false;   //指定需要的是原始數據，非壓縮數據
    final Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), resourceId, options);
    if(bitmap == null){
        Log.e(TAG, "Resource ID "+resourceId + "could not be decode");
        GLES20.glDeleteTextures(1, textureObjectIds, 0);
        return 0;
    }
    //告訴OpenGL後面紋理調用應該是應用於哪個紋理對象
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureObjectIds[0]);
    //設置縮小的時候（GL_TEXTURE_MIN_FILTER）使用mipmap三線程過濾
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR_MIPMAP_LINEAR);
    //設置放大的時候（GL_TEXTURE_MAG_FILTER）使用雙線程過濾
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR);
    //Android設備y座標是反向的，正常圖顯示到設備上是水平顛倒的，解決方案就是設置紋理包裝，紋理T座標（y）設置鏡面重複
    //ball讀取紋理的時候  t範圍座標取正常值+1
    //GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_MIRRORED_REPEAT);
    GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, bitmap, 0);
    bitmap.recycle();
    //快速生成mipmap貼圖
    GLES20.glGenerateMipmap(GLES20.GL_TEXTURE_2D);
    //解除紋理操作的綁定
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 0);
    return textureObjectIds[0];
}

2、在繪製方法onDrawFrame中繪製畫面的同時把水印繪製進去；

/**
       * 繪圖到glsurface
       * 我們將rendermode設置爲glsurfaceview.rendermode_when_dirty，
       * 僅當調用requestrender時調用此方法（=需要更新紋理時）
       * 如果不在髒時設置rendermode，則此方法的最大調用速度爲60fps。
       */
      @Override
      public void onDrawFrame(final GL10 unused) {
         GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
         GLES20.glEnable(GLES20.GL_BLEND);
         //開啓GL的混合模式，即圖像疊加
         GLES20.glBlendFunc(GLES20.GL_ONE, GLES20.GL_ONE_MINUS_SRC_ALPHA)；
         /**
         *中間這裏是你繪製的預覽畫面
         */
     //畫水印（非動態）
       GLES20.glViewport(20, 20, 288, 120);
      mWaterSign.drawFrame(mSignTexId);
       }

這裏最重要的是要開啓GL的混合模式，即圖像疊加，不然你繪製的水印會覆蓋原先的預覽畫面

//開啓GL的混合模式，即圖像疊加
GLES20.glBlendFunc(GLES20.GL_ONE, GLES20.GL_ONE_MINUS_SRC_ALPHA)；

二、動態水印（時間水印）
原理：把時間字符單個轉化爲圖片，然後再把它一個個的繪製在畫布上。如2020-02-14 10:24:30這種時間格式總共包含0123456789 - ：這12個字符，全部先轉成圖片，再去匹配繪製到畫布。
下面是一點的相關的代碼：
注意：時間格式必須爲 yyyy-MM-dd HH:mm:ss ，因爲下面是截取文字，格式不對的話會拋異常。

/**
 * 添加時間水印
 * 原理：將文字轉成圖片，使用OpenGL將圖片畫到視頻上
 * 實現方法：將時間水印所需的文字轉化爲圖片（避免每次實時轉換導致大量內存被消耗），如：2019-09-05 16:52:18  共16張圖片。
 * 每張圖片綁定一個紋理；獲取當前時間切出單個字符，使用OpenGL將對應的字符紋理畫上去。
 * @param time
 * @param x
 * @param y    位於屏幕的（x,y）座標點
 */
private void drawWaterSign(String time, int x, int y) {
   if ("".equals(time)) {
      return;
   }
   //畫水印
   GLES20.glViewport(x, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(0, 1))]);
   GLES20.glViewport(x + 15, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(1, 2))]);
   GLES20.glViewport(x + 15 * 2, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(2, 3))]);
   GLES20.glViewport(x + 15 * 3, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(3, 4))]);
   GLES20.glViewport(x + 15 * 4, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[10]); // -
   GLES20.glViewport(x + 15 * 5, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(5, 6))]);
   GLES20.glViewport(x + 15 * 6, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(6, 7))]);
   GLES20.glViewport(x + 15 * 7, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[10]); // -
   GLES20.glViewport(x + 15 * 8, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(8, 9))]);
   GLES20.glViewport(x + 15 * 9, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(9, 10))]);
   GLES20.glViewport(x + 15 * 11, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(11, 12))]);
   GLES20.glViewport(x + 15 * 12, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(12, 13))]);
   GLES20.glViewport(x + 15 * 13, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[11]); // :
   GLES20.glViewport(x + 15 * 14, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(14, 15))]);
   GLES20.glViewport(x + 15 * 15, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(15, 16))]);
   GLES20.glViewport(x + 15 * 16, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[11]); // :
   GLES20.glViewport(x + 15 * 17, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(17, 18))]);
   GLES20.glViewport(x + 15 * 18, y, 220, 60);
   mWaterSign.drawFrame(mWaterTexId[Integer.parseInt(time.substring(18, 19))]);
}

調用方法：

Android使用Opengl錄像時添加(動態)水印

Android性能優化(三)：響應優化

Android 將引入jar、so包的module打包成jar或者aar文件

Android延時執行方法

Android應用層實現恢復出廠設置功能

如何將本地代碼上傳到GitHub？

https://yachay.unat.edu.pe/blog/index.php?comment_area=format_blog&comment_component=blog&comment_co

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