Classes/iOS/EAGLView.m

/*
     File: EAGLView.m
 Abstract: The EAGLView class is a UIView subclass that renders OpenGL scene.
  Version: 1.7
 
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 */
 
#import "EAGLView.h"
 
#import "ES2Renderer.h"
 
@implementation EAGLView
 
@dynamic animationFrameInterval;
 
// You must implement this method
+ (Class) layerClass
{
    return [CAEAGLLayer class];
}
 
//The GL view is stored in the nib file. When it's unarchived it's sent -initWithCoder:
- (id) initWithCoder:(NSCoder*)coder
{    
    if ((self = [super initWithCoder:coder]))
    {
        // Get the layer
        CAEAGLLayer *eaglLayer = (CAEAGLLayer *)self.layer;
        
        eaglLayer.opaque = TRUE;
        eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:
                                        [NSNumber numberWithBool:FALSE], kEAGLDrawablePropertyRetainedBacking, kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat, nil];
        
        
        m_context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
        
        if (!m_context || ![EAGLContext setCurrentContext:m_context])
        {
            [self release];
            return nil;
        }
        
        m_renderer = [[ES2Renderer alloc] initWithContext:m_context AndDrawable:(id<EAGLDrawable>)self.layer];
        
        if (!m_renderer)
        {
            [self release];
            return nil;
        }
        
        _animating = FALSE;
        displayLinkSupported = FALSE;
        animationFrameInterval = 1;
        displayLink = nil;
        animationTimer = nil;
        
        // A system version of 3.1 or greater is required to use CADisplayLink. The NSTimer
        // class is used as fallback when it isn't available.
        NSString *reqSysVer = @"3.1";
        NSString *currSysVer = [[UIDevice currentDevice] systemVersion];
        if ([currSysVer compare:reqSysVer options:NSNumericSearch] != NSOrderedAscending)
            displayLinkSupported = TRUE;
    }
    
    return self;
}
 
- (void) drawView:(id)sender
{   
    [EAGLContext setCurrentContext:m_context];
    [m_renderer render];
}
 
- (void) layoutSubviews
{
    [m_renderer resizeFromLayer:(CAEAGLLayer*)self.layer];
    [self drawView:nil];
}
 
- (NSInteger) animationFrameInterval
{
    return animationFrameInterval;
}
 
- (void) setAnimationFrameInterval:(NSInteger)frameInterval
{
    // Frame interval defines how many display frames must pass between each time the
    // display link fires. The display link will only fire 30 times a second when the
    // frame internal is two on a display that refreshes 60 times a second. The default
    // frame interval setting of one will fire 60 times a second when the display refreshes
    // at 60 times a second. A frame interval setting of less than one results in undefined
    // behavior.
    if (frameInterval >= 1)
    {
        animationFrameInterval = frameInterval;
        
        if (_animating)
        {
            [self stopAnimation];
            [self startAnimation];
        }
    }
}
 
- (void) startAnimation
{
    if (!_animating)
    {
        if (displayLinkSupported)
        {
            // CADisplayLink is API new to iPhone SDK 3.1. Compiling against earlier versions will result in a warning, but can be dismissed
            // if the system version runtime check for CADisplayLink exists in -initWithCoder:. The runtime check ensures this code will
            // not be called in system versions earlier than 3.1.
            
            displayLink = [NSClassFromString(@"CADisplayLink") displayLinkWithTarget:self selector:@selector(drawView:)];
            [displayLink setFrameInterval:animationFrameInterval];
            [displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
        }
        else
            animationTimer = [NSTimer scheduledTimerWithTimeInterval:(NSTimeInterval)((1.0 / 60.0) * animationFrameInterval) target:self selector:@selector(drawView:) userInfo:nil repeats:TRUE];
        
        _animating = TRUE;
    }
}
 
- (void)stopAnimation
{
    if (_animating)
    {
        if (displayLinkSupported)
        {
            [displayLink invalidate];
            displayLink = nil;
        }
        else
        {
            [animationTimer invalidate];
            animationTimer = nil;
        }
        
        _animating = FALSE;
    }
}
 
- (void) dealloc
{
    [m_renderer release];
    
    
    // tear down context
    if ([EAGLContext currentContext] == m_context)
        [EAGLContext setCurrentContext:nil];
    
    [m_context release];
    
    [super dealloc];
}
 
@end