private void CreateGuiControls()
        {
            var panel = SampleFramework.AddOptions("IBL");

            SampleHelper.AddButton(
                panel,
                "Update environment maps",
                () => _updateEnvironmentMaps = true,
                null);

            for (int i = 0; i < _lightNodes.Length; i++)
            {
                int index = i;
                SampleHelper.AddCheckBox(
                    panel,
                    "Enable image-based light " + i,
                    true,
                    isChecked =>
                {
                    _lightNodes[index].IsEnabled = isChecked;
                });
            }

            SampleHelper.AddCheckBox(
                panel,
                "Colorize image-based lights to show influence zones",
                false,
                isChecked =>
            {
                if (isChecked)
                {
                    _imageBasedLights[0].Color = new Vector3F(1, 0, 0);
                    _imageBasedLights[1].Color = new Vector3F(0, 1, 0);
                    _imageBasedLights[2].Color = new Vector3F(0, 0, 1);
                }
                else
                {
                    _imageBasedLights[0].Color = new Vector3F(1);
                    _imageBasedLights[1].Color = new Vector3F(1);
                    _imageBasedLights[2].Color = new Vector3F(1);
                }
            });

            SampleHelper.AddCheckBox(
                panel,
                "Enable localized reflections",
                true,
                isChecked =>
            {
                _imageBasedLights[1].EnableLocalizedReflection = isChecked;
                _imageBasedLights[2].EnableLocalizedReflection = isChecked;
            });

            SampleHelper.AddSlider(
                panel,
                "Fade-out range",
                "F2",
                0,
                1,
                _imageBasedLights[1].FalloffRange,
                value =>
            {
                _imageBasedLights[1].FalloffRange = value;
                _imageBasedLights[2].FalloffRange = value;
            });

            SampleFramework.ShowOptionsWindow("IBL");
        }