glkview drawinrect delegate method called only once - iphone

Question

I am trying to add GLKViewController to my UserInterfaceViewController.I am using the example project from raywenderlich tutorials(http://www.raywenderlich.com/5235/beginning-opengl-es-2-0-with-glkit-part-2)
Here is my code snippet
#import <UIKit/UIKit.h>
#interface UserInterfaceViewController : UIViewController
#end
#implementation UserInterfaceViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
UIViewController *userInterfaceController = [[UIStoryboard storyboardWithName:#"MainStoryboard" bundle:NULL] instantiateViewControllerWithIdentifier:#"HelloGLKitViewController"];
userInterfaceController.view.frame = CGRectMake(50.0, 100.0, 200.0, 200.0);
[self.view addSubview:userInterfaceController.view];
}
The above code is drawing the context in my UserInterfaceViewController view in the mentioned frame which I am expecting.HelloGLKitViewController is having code to rotate cube in GLKViewControllerDelegate method "update" as mntioned below.but GLKViewControllerDelegate is not getting called when HelloGLKitViewController view to my UserInterfaceViewController view.
#import <GLKit/GLKit.h>
#interface HelloGLKitViewController : GLKViewController
#end
#implementation HelloGLKitViewController
#pragma mark - GLKViewDelegate
- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect {
//glClearColor(_curRed, 0.0, 0.0, 1.0);
glClear(GL_COLOR_BUFFER_BIT);
[self.effect prepareToDraw];
glBindVertexArrayOES(_vertexArray);
glDrawElements(GL_TRIANGLES, sizeof(Indices)/sizeof(Indices[0]), GL_UNSIGNED_BYTE, 0);
}
#pragma mark - GLKViewControllerDelegate
- (void)update {
if (_increasing) {
_curRed += 1.0 * self.timeSinceLastUpdate;
} else {
_curRed -= 1.0 * self.timeSinceLastUpdate;
}
if (_curRed >= 1.0) {
_curRed = 1.0;
_increasing = NO;
}
if (_curRed <= 0.0) {
_curRed = 0.0;
_increasing = YES;
}
float aspect = fabsf(self.view.bounds.size.width / self.view.bounds.size.height);
GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(GLKMathDegreesToRadians(65.0f), aspect, 4.0f, 10.0f);
self.effect.transform.projectionMatrix = projectionMatrix;
GLKMatrix4 modelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, -6.0f);
_rotation += -90 * self.timeSinceLastUpdate;//90 clockwise -90 anticlickwise
modelViewMatrix = GLKMatrix4Rotate(modelViewMatrix, GLKMathDegreesToRadians(0), 1, 0, 0);//GLKMathDegreesToRadians(25) for bending Cube
modelViewMatrix = GLKMatrix4Rotate(modelViewMatrix, GLKMathDegreesToRadians(_rotation), 0, 1, 0);
// modelViewMatrix = GLKMatrix4Translate(modelViewMatrix, self.view.frame.origin.x, self.view.frame.origin.y,0);
// modelViewMatrix = GLKMatrix4Translate(modelViewMatrix, -self.view.bounds.size.width/2, -self.view.bounds.size.height/2,0);
self.effect.transform.modelviewMatrix = modelViewMatrix;
}
#end
What should I do to call GLKViewControllerDelegate update method.

Answer 1

Problem solved: Here is my code
#class HelloGLKitViewController;
#interface UserInterfaceViewController : UIViewController
{
HelloGLKitViewController *myHLKViewController;
}
#end
#implementation UserInterfaceViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
NSLog(#"viewDidLoad of userinterfaceUiViewController");
myHLKViewController = [[UIStoryboard storyboardWithName:#"MainStoryboard" bundle:NULL] instantiateViewControllerWithIdentifier:#"HelloGLKitViewController"];
[self.view addSubview:myHLKViewController.view];
[self addChildViewController:myHLKViewController];
[myHLKViewController didMoveToParentViewController:self];
}
#end
Thanks for the ref link Using GLKView with a UIViewController