iOS Passing values from View Controller to View

[sm4ck]

This should be easy but it is driving me nuts. I am trying to pass a value from a ViewController to a View but it seems to be getting forgetting the value. More specifically, I am trying to get the accelerometer value in my ViewController and then pass this to the View. It appears I am successfully getting the input data correctly and sending it to the View but when I initiate a method within the view the data appears to be uninitialized. Any help would be appreciated.

Code details following. I have tried to remove code that is not relevant for ease of reading but please let me know if you need more info.


GameViewController.h

#import <UIKit/UIKit.h>

@class GameView;


@interface GameViewController : UIViewController <UIAccelerometerDelegate> {
    GameView *game_view;
}

@property (nonatomic, retain) IBOutlet GameView *game;

GameViewController.mm

#import "GameView.h"
#import "GameViewController.h"
#include "Globals.h"


@implementation GameViewController

@synthesize game_view;

- (IBAction)closeGameView:(id)sender
{
	[self.view removeFromSuperview];
}

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

  game_view.acceleration = malloc(sizeof(acceleration));

	// OK, this seems to work so far. I know that I am getting accelerometer
  // readings and it does seem to be passing it to the GameView
  [game_view setAcceleration:acceleration];

}

GameView.h

#import <UIKit/UIKit.h>
#import <OpenGLES/EAGL.h>
#import <OpenGLES/ES1/gl.h>
#import <OpenGLES/ES1/glext.h>

@interface GameView : UIView
{
@private
  UIAcceleration *acceleration;
	// The pixel dimensions of the backbuffer
	GLint backingWidth;
	GLint backingHeight;
	
	EAGLContext *context;
	
	// OpenGL names for the renderbuffer and framebuffers used to render to this view
	GLuint viewRenderbuffer, viewFramebuffer;
	
	// OpenGL name for the depth buffer that is attached to viewFramebuffer, if it exists (0 if it does not exist)
	GLuint depthRenderbuffer;
	
	BOOL animating;
	BOOL displayLinkSupported;
	NSInteger animationFrameInterval;
	id displayLink;
  NSTimer *animationTimer;

}

@property (readonly, nonatomic, getter=isAnimating) BOOL animating;
@property (nonatomic) NSInteger animationFrameInterval;
@property (nonatomic, retain) UIAcceleration *acceleration;

-(void)startAnimation;
-(void)stopAnimation;
-(void)drawView;
- (BOOL)createFramebuffer;
- (void)destroyFramebuffer;
- (void)setupView;

@end

GameView.mm
!!! OK This is where the problem is. When I enter drawView, the values
previously set are no longer set !!!!

#import <QuartzCore/QuartzCore.h>
#import <OpenGLES/EAGLDrawable.h>

#import "AsteroidsView.h"

#include "Asteroid.h"
#include "Camera.h"
#include "Game.h"
#include "Globals.h"
#include "MovableObject.h"
#include "World.h"

// MACROS
#define DEGREES_TO_RADIANS(__ANGLE__) ((__ANGLE__) / 180.0 * M_PI)

@implementation GameView

@synthesize animating;
@synthesize acceleration;
@dynamic animationFrameInterval;



// Updates the OpenGL view
- (void)drawView
{
  
  static Game current_game;
  static Camera main_view;
  static World test_world;
  
  
	// Make sure that you are drawing to the current context
	[EAGLContext setCurrentContext:context];
		
	glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  
		
	// Setup model view matrix
	glLoadIdentity();
  // Move back a bit
  glTranslatef(0.0, 0.0, -3.0);
  
  // Main game "loop" calls this method multiple times.
  // Check if the game is active, if so, go through major game steps.
  // Game not fully implemented yet
  if(current_game.IsActive()){
    // acceleration.x y, and z should have values but they do not!
    current_game.Update(acceleration.x, acceleration.y, acceleration.z);
    current_game.PlaySounds();
    current_game.Draw();
  }
  

 
	glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
	[context presentRenderbuffer:GL_RENDERBUFFER_OES];
}

 

[Luke Redpath]

Why are you doing this?

game_view.acceleration = malloc(sizeof(acceleration));

Shouldn't you just be doing this?

game_view.acceleration = acceleration;

Also, are you setting the acceleration before or after drawView gets called? If after, you probably need to override setAcceleration to call [self setNeedsDisplay].

 

[sm4ck]

Thanks Luke. I tried this but still no luck. I might not be fully understanding your suggestion.

Why are you doing this?

game_view.acceleration = malloc(sizeof(acceleration));

Shouldn't you just be doing this?

game_view.acceleration = acceleration;

I thought the memory allocated might be getting overwritten somehow so wanted to malloc to ensure it was there. I took that out per your suggestion. I also just used [game setAcceleration: acceleration] instead of game_view.acceleration = acceleration

Also, are you setting the acceleration before or after drawView gets called? If after, you probably need to override setAcceleration to call [self setNeedsDisplay].

OK, I put setNeedsDisplay right after the setAcceleration but still having the same problem. My My code now looks like this:

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

  [game_view setAcceleration:acceleration];
  [game_view setNeedsDisplay];

}

I am still having the same problem. Am I missing something here? Any input would be appreciated.

Thanks!

 

[sm4ck]

OK, I seem to have solved this by moving the accelerometer logic to the View. Not sure if this is the optimal solution but it seems to work.