基于video texture（camera流，视频流） 创建一个纹理

public int createTexture(){

  
    int[] mTextures = new int[1];
    GLES20.glGenTextures(1, mTextures , 0);
      
GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTextures[0]);
GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,
        GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE);
GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,
        GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE);
GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,
        GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST);
GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,
        GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_NEAREST);

     return mTextures[0];
   
}

//比如对于camera preview 的时候，在创建SurfaceTexture的时候，就要基于这个textureId 去创建，这样就可以连接到camera preview 数据流到这个纹理上。

大概的过程如下：

1）

int texture =createTexture();
surfaceTexture=new SurfaceTexture(texture);

2）

mCamera2.setPreviewTexture（surfaceTexture);//设置到camera 数据流
surfaceTexture.setOnFrameAvailableListener(new SurfaceTexture.OnFrameAvailableListener() {
    @Override    public void onFrameAvailable(SurfaceTexture surfaceTexture) {        requestRender();    }});

3）

public void onDrawFrame(GL10 gl) {
    if(surfaceTexture!=null){
        surfaceTexture.updateTexImage();  //更新数据流到opengl 纹理上面去。
    }
   
}

4）顶点着色器，片元着色去要进行如下设置

private final String mVss =
        "attribute vec2 a_Position;\n" +
        "attribute vec2 a_TexCoord;\n" +
        "varying vec2 v_TexCoord;\n" +
        "void main() {\n" +
        "  v_TexCoord = a_TexCoord;\n" +
        "  gl_Position = vec4(a_Position.x, a_Position.y, 0.0, 1.0);\n" +
        "}";

private final String mFss =
        "#extension GL_OES_EGL_image_external : require\n" +
        "precision mediump float;\n" +
        "uniform samplerExternalOES u_Texture;\n" +
        "varying vec2 v_TexCoord;\n" +
        "void main() {\n" +
        "  gl_FragColor = texture2D(u_Texture,v_TexCoord);\n" +
        "}";