Android 9 Development Cookbook - Third Edition

Creating an OpenGL rendered class

The last step is to create the GLSurfaceView.Renderer class and implement the following three callbacks:

• onSurfaceCreated()
• onDrawFrame()
• onSurfaceChanged()

Following is the code:

class GLRenderer implements GLSurfaceView.Renderer {    public void onSurfaceCreated(GL10 unused, EGLConfig config) {        GLES20.glClearColor(0.5f, 0.5f, 0.5f, 1.0f);    }    public void onDrawFrame(GL10 unused) {        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);    }    public void onSurfaceChanged(GL10 unused, int width, int height) {        GLES20.glViewport(0, 0, width, height);    }}

Right now, all we're doing with this class is setting up the callbacks and clearing the screen using the color we specify with glClearColor() (gray in this case).