OpenGLES通过SurfaceTexture预览摄像头画面

attribute vec4 av_Position;//顶点位置
attribute vec2 af_Position;//纹理位置
varying vec2 v_texPo;//纹理位置  与fragment_shader交互
uniform mat4 u_Matrix;//矩阵变换

void main() {
    v_texPo = af_Position;
    gl_Position = av_Position * u_Matrix;
}

#extension GL_OES_EGL_image_external : require //申明使用扩展纹理
precision mediump float;//精度 为float
varying vec2 v_texPo;//纹理位置  接收于vertex_shader
uniform samplerExternalOES  sTexture;//加载流数据(摄像头数据)
void main() {
    gl_FragColor=texture2D(sTexture, v_texPo);
}

/**
    * 创建摄像头预览扩展纹理
    */
   private void createCameraRenderTexture() {
       int[] textureIds = new int[1];
       GLES20.glGenTextures(1, textureIds, 0);
       cameraRenderTextureId = textureIds[0];
       GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, cameraRenderTextureId);
       //环绕（超出纹理坐标范围）  （s==x t==y GL_REPEAT 重复）
       GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_REPEAT);
       GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_REPEAT);
       //过滤（纹理像素映射到坐标点）  （缩小、放大：GL_LINEAR线性）
       GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR);
       GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR);

       surfaceTexture = new SurfaceTexture(cameraRenderTextureId);
       surfaceTexture.setOnFrameAvailableListener(this);

       if (onSurfaceListener != null) {
           //这里相机拿到surfaceTexture绑定
           onSurfaceListener.onSurfaceCreate(surfaceTexture);
       }

       // 解绑扩展纹理
       GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, 0);
   }

camera.setPreviewTexture(surfaceTexture);

@Override
    public void onDrawFrame() {
        //调用触发onFrameAvailable
        surfaceTexture.updateTexImage();
        //清空颜色
        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
        //设置背景颜色
        GLES20.glClearColor(1.0f, 1.0f, 1.0f, 1.0f);

        //使用程序
        GLES20.glUseProgram(program);

        //绑定fbo
        GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, fboId);

        //摄像头预览扩展纹理赋值
        GLES20.glActiveTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES);
        GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, cameraRenderTextureId);
        GLES20.glUniform1i(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, 0);

        //给变换矩阵赋值
        GLES20.glUniformMatrix4fv(uMatrix, 1, false, matrix, 0);

        GLES20.glEnableVertexAttribArray(avPosition);
        GLES20.glEnableVertexAttribArray(afPosition);

        //使用VBO设置纹理和顶点值
        useVboSetVertext();

        //绘制 GLES20.GL_TRIANGLE_STRIP:复用坐标
        GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, vertexCount);
        GLES20.glDisableVertexAttribArray(avPosition);
        GLES20.glDisableVertexAttribArray(afPosition);

        GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);

        //渲染显示
        cameraRender.onDraw(fboTextureId);
    }

 //变换矩阵 location
private int uMatrix;

 //变换矩阵
private float[] matrix = new float[16];

public void onSurfaceCreated() {
    //...
uMatrix = GLES20.glGetUniformLocation(program, "u_Matrix");
}
 
 @Override
 public void onDrawFrame() {
 //...
 //给变换矩阵赋值
GLES20.glUniformMatrix4fv(uMatrix, 1, false, matrix, 0); 
 }


/**
 * 初始化矩阵
 */
public void resetMatirx() {
    //初始化
    Matrix.setIdentityM(matrix, 0);
}


/**
 * 旋转
 *
 * @param angle
 * @param x
 * @param y
 * @param z
 */
public void setAngle(float angle, float x, float y, float z) {
    //旋转
    Matrix.rotateM(matrix, 0, angle, x, y, z);
}

public void previewAngle(Context context) {
        int angle = ((WindowManager) context.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay().getRotation();
        render.resetMatirx();
        switch (angle) {
            case Surface.ROTATION_0:
                if (cameraId == Camera.CameraInfo.CAMERA_FACING_BACK) {
                    render.setAngle(90, 0, 0, 1);
                    render.setAngle(180, 1, 0, 0);
                } else {
                    render.setAngle(90f, 0f, 0f, 1f);
                }

                break;
            case Surface.ROTATION_90:
                if (cameraId == Camera.CameraInfo.CAMERA_FACING_BACK) {
                    render.setAngle(180, 0, 0, 1);
                    render.setAngle(180, 0, 1, 0);
                } else {
                    render.setAngle(90f, 0f, 0f, 1f);
                }
                break;
            case Surface.ROTATION_180:
                if (cameraId == Camera.CameraInfo.CAMERA_FACING_BACK) {
                    render.setAngle(90f, 0.0f, 0f, 1f);
                    render.setAngle(180f, 0.0f, 1f, 0f);
                } else {
                    render.setAngle(-90, 0f, 0f, 1f);
                }
                break;
            case Surface.ROTATION_270:
                if (cameraId == Camera.CameraInfo.CAMERA_FACING_BACK) {
                    render.setAngle(180f, 0.0f, 1f, 0f);
                } else {
                    render.setAngle(0f, 0f, 0f, 1f);
                }
                break;
        }
    }