Date/Time:       2014-09-17T20:26:15Z
OS Version:      iPhone OS 8.0 (12A365)
Report Version:  104

Exception Type:  SIGSEGV
Exception Codes: SEGV_ACCERR at 0x1
Crashed Thread:  0

Thread 0 Crashed:
0   libGPUSupportMercury.dylib           0x2a4f88fe gldGetBufferAllocationIdentifiers + 194
1   libGPUSupportMercury.dylib           0x2a4f93cb gpusSubmitDataBuffers + 108
2   libGPUSupportMercury.dylib           0x2a4f9249 gldCreateContext + 206
3   GLEngine                             0x2613c93b gliCreateContextWithShared + 600
4   OpenGLES                             0x26218ab3 glGetFramebufferParameteriAPPLE + 776
5   CoreImage                            0x23e88b8b 0x23dea000 + 650123
6   libdispatch.dylib                    0x314558b7 0x31454000 + 6327
7   libdispatch.dylib                    0x314564fb dispatch_once_f + 60
8   CoreImage                            0x23e88afb 0x23dea000 + 649979
9   CoreImage                            0x23e06c79 0x23dea000 + 117881
10  CoreUI                               0x29478837 CUIEqualRenditionKeysIgnoringAttribute + 71800
11  libsystem_pthread.dylib              0x315b9dcf sched_get_priority_min + 64
12  libsystem_platform.dylib             0x315b2867 _os_once + 40
13  libsystem_pthread.dylib              0x315b7f8b pthread_once + 48
14  CoreUI                               0x294787d9 CUIEqualRenditionKeysIgnoringAttribute + 71706
15  CoreUI                               0x2947faf7 CUIEqualRenditionKeysIgnoringAttribute + 101176
16  UIKit                                0x26f649db _UIGraphicsEndLetterpressWithStyle + 20792
17  UIKit                                0x26cf2875 UIGraphicsEndImageContext + 7838
18  UIKit                                0x26cf1fb5 UIGraphicsEndImageContext + 5598
19  UIKit                                0x26fe3db9 _UINavigationButtonUpdateAccessibilityBackgroundsForBlendMode + 287838
20  UIKit                                0x26cf19c7 UIGraphicsEndImageContext + 4080
21  UIKit                                0x26d8c1b1 UICeilToViewScale + 55778
22  UIKit                                0x26d70143 _UIBarHairlineshadowColorForBarStyle + 10164
23  UIKit                                0x26ce2b37 0x26cd6000 + 52023
24  QuartzCore                           0x2670accd CAbackingStoreGetTypeID + 894
25  QuartzCore                           0x267066b5 CARenderServerGetServerPort + 5366
26  UIKit                                0x26cf5183 UIGraphicsGetimageFromCurrentimageContext + 2068
27  UIKit                                0x26cf1fb5 UIGraphicsEndImageContext + 5598
28  UIKit                                0x26d6efc5 _UIBarHairlineshadowColorForBarStyle + 5686
29  UIKit                                0x26d6ec63 _UIBarHairlineshadowColorForBarStyle + 4820
30  UIKit                                0x26d6e3cd _UIBarHairlineshadowColorForBarStyle + 2622
31  UIKit                                0x26fd5a6f _UINavigationButtonUpdateAccessibilityBackgroundsForBlendMode + 229652
32  UIKit                                0x26d6b837 _UIAccessibilityReduceMotion + 16948
33  UIKit                                0x26ce53d9 _UIApplicationLinkedOnorAfter + 2526
34  UIKit                                0x26ce535d _UIApplicationLinkedOnorAfter + 2402
35  UIKit                                0x26d6b24d _UIAccessibilityReduceMotion + 15434
36  UIKit                                0x26fd7ef9 _UINavigationButtonUpdateAccessibilityBackgroundsForBlendMode + 239006
37  UIKit                                0x26d6b0b3 _UIAccessibilityReduceMotion + 15024
38  UIKit                                0x26dc516f UIRectIntegralWithScale + 1040
39  Pogoplug                             0x001bccc9 __41-[InitialSlidingViewController didSignIn]_block_invoke (InitialSlidingViewController.m:216)
40  libdispatch.dylib                    0x314558cb 0x31454000 + 6347
41  libdispatch.dylib                    0x314558b7 0x31454000 + 6327
42  libdispatch.dylib                    0x314590bf _dispatch_main_queue_callback_4CF + 720
43  CoreFoundation                       0x2380dbe9 CFRunLoopTimerSetTolerance + 3370
44  CoreFoundation                       0x2380c2e9 _CFRunLoopGet2b + 2926
45  CoreFoundation                       0x2375a621 CFRunLoopRunSpecific + 474
46  CoreFoundation                       0x2375a433 CFRunLoopRunInMode + 104
47  GraphicsServices                     0x2ab080a9 GSEventRunModal + 134
48  UIKit                                0x26d44809 UIApplicationMain + 1438
49  Pogoplug                             0x0012c4bf main (main.m:11)
50  libdyld.dylib                        0x31475aaf _tlv_atexit + 8

MenuViewController *menuVC = [[MenuViewController alloc] initWithNibName:nil bundle:nil];
NavControllerPortrait *navController = [[NavControllerPortrait alloc] initWithRootViewController:menuVC];

CELoginViewController *loginVC = [[CELoginViewController alloc] initWithNibName:nil bundle:nil];
NavControllerPortrait *nav = [[NavControllerPortrait alloc] initWithRootViewController:loginVC];

解决方法

Using Bullet in Your iOS Application

All that remains is to build an application that actually uses Bullet and displays 3D objects. Apple's GLKit framework makes it relatively easy.

Make the view controller class generated by Xcode's Single View Application template into a subclass of GLKViewController instead of UIViewCintroller. The PViewController.h file in the tutorial sample code contains the following lines:

#import <GLKit/GLKit.h>
 PViewController : @interfaceGLKViewController

Next,edit the MainStoryboard.storyboard file generated by Xcode's Single View Application template. Set the class of the generated view to GLKView using Xcode's Identity inspector,shown in figure 12.

Add the GLKit and OpenGLES frameworks to the project. The easiest way is to edit the project's Build Phases,as shown in figure 13. Press the + button in the Link Binary with Libraries section to add frameworks.

If you build and run the tutorial project Now,you should see a black screen. The next step is to create a physics simulation and draw something more interesting.

The tutorial source code includes a file named PAppDelegate.mm. The .mm extension tells Xcode to compile the file as Objective-C++ code intermixing C++ and Objective-C. The following code declares instance variables to store Bullet physics objects:

#import "PAppDelegate.h"
#include "btBulletDynamicsCommon.h"
#include <map>


 < *,*> 
   GModelShapeMap;


  ()
{
    *collisionConfiguration;
    *dispatcher;
    *overlappingPairCache;
    *solver;
    *dynamicsWorld;
   *> collisionShapes;
   
    modelShapeMap;
}

@endtypedefstd::mapPPhysicsObjectbtCollisionObject@interfacePAppDelegatebtDefaultCollisionConfigurationbtCollisiondispatcherbtbroadphaseInterfacebtSequentialImpulseConstraintSolverbtdiscreteDynamicsWorldbtAlignedobjectArray<btCollisionShapeGModelShapeMap

The GModelShapeMap modelShapeMap variable is used to store the relationships between Objective-C objects representing Boxes and spheres and the corresponding shapes simulated by Bullet. A C++ map is a standard class similar in function to Cocoa Touch'sNSDictionary class.

The physics simulation is initialized in PAppDelegate's -application:didFinishLaunchingWithOptions: method that's part of the Cocoa Touch standard application delegate protocol. The simulation is configured to use Earth's gravitational acceleration of -9.81 meters per second2. Comments explain the steps needed to initialize Bullet. Don't worry if it doesn't make much sense to you. It's boilerplate code.

/////////////////////////////////////////////////////////////////
// Creates needed physics simulation objects and configures
// properties such as the acceleration of gravity that seldom
// if ever change while the application executes.
- ()application:( *)application 
   didFinishLaunchingWithOptions:( *)launchOptions
{
    ///collision configuration contains default setup for memory,// collision setup. Advanced users can create their own 
   // configuration.
     =  
      ();
   
    ///use the default collision dispatcher. For parallel 
   // processing you can use a diffent dispatcher 
   // (see Extras/BulletMultiThreaded)
     = 	  
      ();
   
    ///btDbvtbroadphase is a good general purpose broadphase. You 
   // can also try out btAxis3Sweep.
     =  ();
   
    ///the default constraint solver. For parallel processing you 
   // can use a different solver (see Extras/BulletMultiThreaded)
     =  ;
   
     = 
       (,);
   
    ->setGravity(());
   
   return YES;
}BOOLUIApplicationNSDictionarycollisionConfigurationnewbtDefaultCollisionConfigurationdispatchernewbtCollisiondispatchercollisionConfigurationoverlappingPairCachenewbtDbvtbroadphasesolvernewbtSequentialImpulseConstraintSolverdynamicsWorldnewbtdiscreteDynamicsWorlddispatcheroverlappingPairCachesolvercollisionConfigurationdynamicsWorldbtVector30,-9.81,0

PAppDelegate's -applicationWillTerminate: method tears down the simulation built in -application:didFinishLaunchingWithOptions:. It's not necessary to implement -applicationWillTerminate: in the tutorial sample code because when the application terminates,iOS will automatically reclaim the memory and other resources consumed by the physics engine. The code is provided in PAppDelegate.mm as example to follow if you ever need to clean up the physics engine while the application continues to execute.

PAppDelegate provides the following -physicsUpdateWithelapsedtime: method. Call the method periodically to give the physics engine opportunities to recalculate object positions and orientations.

/////////////////////////////////////////////////////////////////
// Turn the crank on the physics simulation to calculate 
// positions and orientations of collision shapes if
// necessary. The simulation performs up to 32 interpolation
// steps depending on the amount of elapsed time,and each step
// represents 1/120 seconds of elapsed time.
- ()physicsUpdateWithelapsedtime:()seconds;
{
   dynamicsWorld->stepSimulation(seconds,/);
}voidNSTimeInterval321120.0f

That's all it takes to start using Bullet physics for iOS. The simulation doesn't produce any interesting results unless some objects are added and set in motion to collide with each other. It's time to create,register,and draw physics objects.

GLKit provides most of the features needed. The tutorial project includes files named sphere.h and cube.h containing data declarations for 3D shapes. The data consists of vertex positions and "normal" vectors. Each shape is drawn as a list of connected triangles. The normal vectors provide information used to calculate how much simulated light reflects from each triangle.

The PViewController class implements all of the drawing for the tutorial. The drawing code is suboptimal to keep the code simple,and it turns out not to matter at run time. Profiling the tutorial code reveals that less than 20% of the application's execution time is spent drawing. Even if the drawing code is removed entirely,the application only runs 20% faster.

PViewController declares the following properties. The baseEffect property stores an instance of GLKit's GLKBaseEffect class. Modern GPUs are programmable allowing almost unlimited flexibility when rendering 3D graphics. The programs running on the GPU are sometimes called effects. GLKBaseEffect encapsulates the GPU programs needed by simple applications so that you don't need to dive into GPU programming when getting started.

@interface  ()

@property (strong,nonatomic,readwrite)
    *baseEffect;
@property (strong,readwrite) 
    *BoxPhysicsObjects;
@property (strong,readwrite) 
    *spherePhysicsObjects;
@property (strong,readwrite) 
    *immovableBoxPhysicsObjects;
   
@endPViewControllerGLKBaseEffectNSMutableArrayNSMutableArrayNSMutableArray

Other than baseEffect,the other properties all store arrays of Objective-C objects representing spheres and Boxes in the simulation. Bullet only recalculates positions for physics objects that have mass. Objects created with zero mass are therefore immovable within the simulation. They don't become displaced when other objects collide or fall in response to gravity. The immovableBoxPhysicsObjects property stores an array of zero mass Boxes used to form a floor. Without a few immovable objects in the simulation,all of the other objects would quickly fall out of view as the result of simulated gravity.

Two GLKViewController methods provide the key to drawing with GLKit: -update and -glkView:drawInRect:. The –update method is called periodically in sync with the iOS device display refresh rate. The display always refreshes 60 times per second,butGLKViewController's default behavior is to call –update at 30Hz. In other words, –update is called once for every two display refreshes. GLKViewController can be configured to call –update at other rates,but 30 times per second works well for simulations. Right after calling –update, GLKViewController tells the view it controls to display,and the view calls back to GLKViewController's -glkView:drawInRect:. Therefore,you implement simulation update in –update and implement custom 3D drawing code in -glkView:drawInRect:.

/////////////////////////////////////////////////////////////////
// This method is called automatically at the update rate of the 
// receiver (default 30 Hz). This method is implemented to
// update the physics simulation and remove any simulated objects
// that have fallen out of view.
- ()update
{
    *appDelegate = 
      [[] ];
   
   [appDelegate :
      .];

   // Remove objects that have fallen out of view from the 
   // physics simulation
   [ ];
}voidPAppDelegateUIApplication sharedApplicationdelegatephysicsUpdateWithelapsedtimeselftimeSinceLastUpdateselfremoveOutOfViewObjects

The following drawing code sets baseEffect properties to match the orientation of the iOS device,specifies perspective,positions a light,and prepares for drawing 3D objects. Theaspect ratio is the ratio of a view's width to its height. The aspect ratio may change when an iOS device is rotated from portrait orientation to landscape and back. Perspectivedefines how much of the 3D scene is visible at once and how objects in the distance appear smaller than objects up close.

In the real world,we only see objects that reflect light into our eyes. We perceive the shape of objects because different amounts of light reflect for different parts of the objects. Setting the baseEffect's light position controls how OpenGL calculates the amount of simulated light reflected off each part of a virtual 3D object. Calling [self.baseEffect preparetoDraw] tells the base effect to prepare a suitable GPU program for execution.

/////////////////////////////////////////////////////////////////
// GLKView delegate method: Called by the view controller's view
// whenever Cocoa Touch asks the view controller's view to
// draw itself. (In this case,render into a frame buffer that
// shares memory with a Core Animation Layer)
- ()glkView:( *)view drawInRect:()rect
{
   // Calculate the aspect ratio for the scene and setup a 
   // perspective projection
      aspectRatio = 
   ()view. / ()view.;
   
   // Set the projection to match the aspect ratio
   .. = 
   (
      (),// Standard field of view
      aspectRatio,// Don't make near plane too close
      ); // Far arbitrarily far enough to contain scene
   
   // Configure a light
   ... = 
   (,);// Directional light
      
   [. ];

   // Clear Frame Buffer (erase prevIoUs drawing)
   (|);
   
   [ ];
   [ ];      
}voidGLKViewCGRectconstGLfloatGLfloatdrawableWidthGLfloatdrawableHeightselfbaseEffecttransform.projectionMatrixGLKMatrix4MakePerspectiveGLKMathdegreesToradians35.0f0.2f200.0fselfbaseEffectlight0positionGLKVector4Make0.6f1.0f0.4f0.0fselfbaseEffectpreparetoDrawglClearGL_COLOR_BUFFER_BITGL_DEPTH_BUFFER_BITselfdrawPhysicssphereObjectsselfdrawPhysicsBoxObjects

OpenGL ES is a technology for controlling GPUs. Parts of OpenGL ES execute on the GPU itself,and other parts execute on the cpu. Programs call a library of C functions provided by OpenGL to tell OpenGL what to do. The glClear() function,called in the tutorial's -glkView:drawInRect:, erases prevIoUs drawing and discards prevIoUsly calculated information about which 3D objects are in front of others.

PViewController's –drawPhysicssphereObjects and –drawPhysicsBoxObjects methods draw spheres and Boxes with positions and orientations calculated by the physics engine. Without going into a lot of detail,each of the methods calls OpenGL ES functions to specify where to find vertex data defining triangles. Then the triangles are drawn by calling code similar to the following:

      // Draw triangles using the first three vertices in the 
      // currently bound vertex buffer
      (,// Start with first vertex in currently bound buffer
         sphereNumVerts);glDrawArraysGL_TRIANGLES0

OpenGL ES can only draw points,lines segments,and triangles. Complex shapes are composed of many triangles. The shapes in this tutorial are defined in sphere.h and cube.h. The shapes were initially drawn in a free open source 3D modeling application called Blender. Modeling is the term used by artists who create 3D shapes. The created models are exported from Blender in .obj file format and then converted into C header files suitable for direct use with OpenGL. Conversion is performed by an open source Perl language script.

It takes a little more work to setup GLKit. PViewController's -viewDidLoad method shows representative boilerplate code. This article glosses over methods like PViewController's –addRandomPhysicsObject. The code for adding physics objects is straightforward and particular to this tutorial. You'll most likely add different objects with different logic in your physics simulation projects.

Conclusion

The simulation provides remarkably complex and varied interaction between objects. The downloadable code is available in two variants. The Physics zip file (3dphyslibios_physics.zip) contains a Physics folder with an Xcode project. If you have built the Bullet demo applications for Mac OS X,you can copy the Physics folder into your bullet-2.80-rev2531 folder,double-click the Physics.xcodeproj file and press Run. A separate larger PhysicsPlusBullet zip file (3dphyslibios_physicsplusbullet.zip) contains the tutorial example and the needed Bullet source code combined. As always with open source,it's better to get the source code directly from the maintainers instead of grabbing a snapshot preserved in a tutorial's .zip file. Nevertheless,if you're impatient,the PhysicsPlusBullet zip file will get you up and running quickly.

This article provided a whirlwind tour of two large and powerful frameworks,Bullet and GLKit. It's not difficult to combine the two technologies in iOS applications. Like many open source libraries,Bullet is relatively easy to compile for iOS in spite of quirks related to the tools and coding style used by the library's authors. GLKit enables development of interesting and visually complex 3D applications with very little code. The tutorial implements all of its drawing in about 200 lines of code including comments and blank lines.

If you are interested in a more thorough introduction to 3D graphics concepts and GLKit,my new book, Learning OpenGL ES for iOS: A Hands-on Guide to Modern 3D Graphics Programming,is complete and available Now as a Rough Cut electronic edition. Look for the title at your favorite bookstore in the fall. Free sample codefrom the book is available.