Android OpenGL应用程序第二次启动时显示白屏

Question

My game displays texture correctly in the first launch, then I exit and launch it again and display nothing but white screen. I think there are some problems with texture loading and android activity life-cycle such as clean up things when pause or destroy. The funny thing is it only display white screen when i run it, but display perfectly well when i debug. Please give me some of your advice, thank you.

Answer 1

My experience so far:

• Create your textures in power of two and make sure you scale and clip them to the right ratio when you draw.
• Don't stick to RBGA_8888 when you can do ALPHA_8 (text rendering)
• Do whatever you can do in OnSurfaceCreated before you get called in OnSurfaceDraw
• Avoid the GL11 context cast. Some things won't work eg glColor4ub will compile but not work.
• Balance your calls of enable and disable for each component draw your call into your scene graph.
• Pre-allocate your nio buffers
• Use DrawElements but for the simplest shapes of one vertice
• Test on as many devices as you can. Just don't settle for the emulator eg non power of twos work on emulator but not on the phone.
• If you can then use the on demand drawing.
• Use the trick of putting a wait in the onTouchEvent call for 20ms and a notify in your onDraw to reduce the deluge of motion events you have to process. You can bypass onTouchEven and use a lower call to save some cycles as well.
• Use texture atlas as much as you can eg to draw score and text or animations
• Disable the fancy rendering options (DITHER_TEST etc...) Unless you crave a realistic rendering on textures.
• If you draw in 2D, then disable the DEPTH_TEST
• Don't forget the Bitmap.recycle() call when you are done binding your textures.
• Avoid Object creation destruction (PointF Rect) in your rendering routines. GC calls will slow down your frame rate.
• Preload your textures extensively. don't wait until you draw at the last minute to bind your textures. The lag is noticable if you do so it's better at app start up time.

Answer 2

You should use the onPause and onResume methods, if its not solving the problem I will add more suggestions. I had the same problem a few months ago.

@Override
protected void onPause() {
    super.onPause();

    mGLView.onPause();
}

@Override
protected void onResume() {
    super.onResume();

    mGLView.onResume();
}

Ok then maybe:

public void onSurfaceChanged(GL10 gl, int w, int h) {
    gl.glViewport(0, 0, w, h);
}

Answer 3

Are you reloading the textures in onSurfaceCreated() or in another place? You'll want to have that stuff in onSurfaceCreated().