import com.google.vr.sdk.base.GvrActivity; //导入依赖的package包/类
public MyScreenController(GvrActivity ctx) {
	buttonLeft = new VRTextureButton(2, 2, "arrow_left.png", new VRTextureButton.VRClickListener() {
		@Override
		public void onClickListener() {
			sceneIndex--;
			if (sceneIndex < 0) {
				sceneIndex = scenes.size() - 1;
			}
		}
	});
	buttonLeft.setPosition(-3, -3, -10);
	buttonRight = new VRTextureButton(2, 2, "arrow_right.png", new VRTextureButton.VRClickListener() {
		@Override
		public void onClickListener() {
			sceneIndex++;
			if (sceneIndex >= scenes.size()) {
				sceneIndex = 0;
			}
		}
	});
	buttonRight.setPosition(3, -3, -10);

	//
	// The distortion correction can be done at the vertex level adding a Shader Plugin to the scene
	//
	ShaderPlugin lensDistortionCorrection = null;
	if (VRActivity.USE_VERTEX_DISPLACEMENT_LENS_DISTORTION) {
		GvrView gvrView = ctx.getGvrView();
		float coefs[] = PincushionUtils.approximateInverse(gvrView.getGvrViewerParams().getDistortion());
		float maxRadius = PincushionUtils.getMaxRadius(gvrView.getScreenParams(), gvrView.getGvrViewerParams());
		lensDistortionCorrection = new LensDistortionShaderPlugin(coefs[0], coefs[1], coefs[2], coefs[3], coefs[4], coefs[5], maxRadius * maxRadius);
	}

	Scene scene = new ObjLoaderScene(ctx);
	scene.addChild(buttonLeft.object3d);
	scene.addChild(buttonRight.object3d);
	if (VRActivity.USE_VERTEX_DISPLACEMENT_LENS_DISTORTION) {
		scene.setShaderPlugin(lensDistortionCorrection);
	}
	scenes.add(scene);

	scene = new CubesScene(ctx);
	scene.addChild(buttonLeft.object3d);
	scene.addChild(buttonRight.object3d);
	if (VRActivity.USE_VERTEX_DISPLACEMENT_LENS_DISTORTION) {
		scene.setShaderPlugin(lensDistortionCorrection);
	}
	scenes.add(scene);

	sceneHUD = new CrossHudScene();
}