/*

     File: GLGravityAppDelegate.m

 Abstract: The GLGravityAppDelegate class is the app delegate that ties 

 everything together. It updates the acceletometer values used to draw 

 OpenGL content in the GLGravityView class.

  Version: 2.2

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*/

#import "GLGravityAppDelegate.h"

#import "GLGravityView.h"

// CONSTANTS

#define kAccelerometerFrequency     100.0 // Hz

#define kFilteringFactor            0.1

@implementation GLGravityAppDelegate

@synthesize window;

@synthesize glView;

- (void) applicationDidFinishLaunching:(UIApplication *)application

{

    [glView startAnimation];

    //Configure and start accelerometer

    [[UIAccelerometer sharedAccelerometer] setUpdateInterval:(1.0 / kAccelerometerFrequency)];

    [[UIAccelerometer sharedAccelerometer] setDelegate:self];   

}

- (void) applicationWillResignActive:(UIApplication *)application

{

    [glView stopAnimation];

}

- (void) applicationDidBecomeActive:(UIApplication *)application

{

    [glView startAnimation];

}

- (void)applicationWillTerminate:(UIApplication *)application

{

    [glView stopAnimation];

}

- (void) dealloc

{

    [window release];

    [glView release];

    [super dealloc];

}

- (void)accelerometer:(UIAccelerometer*)accelerometer didAccelerate:(UIAcceleration*)acceleration

{

    //Use a basic low-pass filter to only keep the gravity in the accelerometer values

    accel[0] = acceleration.x * kFilteringFactor + accel[0] * (1.0 - kFilteringFactor);

    accel[1] = acceleration.y * kFilteringFactor + accel[1] * (1.0 - kFilteringFactor);

    accel[2] = acceleration.z * kFilteringFactor + accel[2] * (1.0 - kFilteringFactor);

    //Update the accelerometer values for the view

    [glView setAccel:accel];

}

@end