EAGLView.m

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

#import "EAGLView.h"

#define USE_DEPTH_BUFFER 1

@interface EAGLView (EAGLViewPrivate)

- (BOOL)createFramebuffer;
- (void)destroyFramebuffer;

@end

@interface EAGLView (EAGLViewSprite)

- (void)setupView;

@end

@implementation EAGLView

@synthesize applicationResignedActive;

+ (Class) layerClass {
	return [CAEAGLLayer class];
}

- (id)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame: frame]) {
        CAEAGLLayer *eaglLayer = (CAEAGLLayer*) self.layer;
        
        eaglLayer.opaque = YES;
        
        eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:
                                        [NSNumber numberWithBool:FALSE], kEAGLDrawablePropertyRetainedBacking, kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat, nil];
        
        
        context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];
        
        if(!context || ![EAGLContext setCurrentContext:context] || ![self createFramebuffer]) {
            return nil;
        }
        
        animationInterval = 1.0 / 60.0;
        
        [self setupView];
        [self drawView];
        
        return self;
    }
    
    return nil;
}

- (void)layoutSubviews {
    [EAGLContext setCurrentContext:context];
    [self destroyFramebuffer];
    [self createFramebuffer];
    [self drawView];
}

- (BOOL)createFramebuffer {
    glGenFramebuffersOES(1, &viewFramebuffer);
    glGenRenderbuffersOES(1, &viewRenderbuffer);
    
    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
    [context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(id<EAGLDrawable>)self.layer];
    glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, viewRenderbuffer);
    
    glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth);
    glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);
    
    if(USE_DEPTH_BUFFER) {
        glGenRenderbuffersOES(1, &depthRenderbuffer);
        glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthRenderbuffer);
        glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES, backingWidth, backingHeight);
        glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, depthRenderbuffer);
    }
    
    if(glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) != GL_FRAMEBUFFER_COMPLETE_OES) {
        NSLog(@"failed to make complete framebuffer object %x", glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES));
        return NO;
    }
    
    return YES;
}

- (void)destroyFramebuffer {
    glDeleteFramebuffersOES(1, &viewFramebuffer);
    viewFramebuffer = 0;
    glDeleteRenderbuffersOES(1, &viewRenderbuffer);
    viewRenderbuffer = 0;
    
    if(depthRenderbuffer) {
        glDeleteRenderbuffersOES(1, &depthRenderbuffer);
        depthRenderbuffer = 0;
    }
}

- (void)startAnimation {
    animationTimer = [NSTimer scheduledTimerWithTimeInterval:animationInterval target:self selector:@selector(drawView) userInfo:nil repeats:YES];
    animationStarted = [NSDate timeIntervalSinceReferenceDate];
}

- (void)stopAnimation {
    [animationTimer invalidate];
    animationTimer = nil;
}

- (NSTimeInterval)animationInterval {
    return animationInterval;
}

- (void)setAnimationInterval:(NSTimeInterval)interval {
    animationInterval = interval;
    
    if(animationTimer) {
        [self stopAnimation];
        [self startAnimation];
    }
}

- (void)setupView {
    glViewport(0, 0, backingWidth, backingHeight);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrthof(0, backingWidth, 0, backingHeight, -1.0f, 1.0f);
    glMatrixMode(GL_MODELVIEW);
    
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    
    glEnableClientState(GL_VERTEX_ARRAY);
}

- (void)drawView {
    // the NSTimer seems to fire one final time even though it's been invalidated
    // so just make sure and not draw if we're resigning active
    if (self.applicationResignedActive) return;
    
    [EAGLContext setCurrentContext:context];
    
    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
    
    [delegate drawView:self forTime:([NSDate timeIntervalSinceReferenceDate] - animationStarted)];
    
    /*
     glRotatef(3.0f, 0.0f, 0.0f, 1.0f);
     
     glClear(GL_COLOR_BUFFER_BIT);
     glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
     */
    
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
    [context presentRenderbuffer:GL_RENDERBUFFER_OES];
}

- (void)dealloc {
    [self stopAnimation];
    
    if([EAGLContext currentContext] == context) {
        [EAGLContext setCurrentContext:nil];
    }
    
    context = nil;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    if ([(id)delegate respondsToSelector:@selector(touchesBegan:withEvent:)])
        [delegate touchesBegan:touches withEvent:event];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    if ([(id)delegate respondsToSelector:@selector(touchesMoved:withEvent:)])
        [delegate touchesMoved:touches withEvent:event];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    if ([(id)delegate respondsToSelector:@selector(touchesEnded:withEvent:)])
        [delegate touchesEnded:touches withEvent:event];
}

- (id <EAGLViewDelegate>)delegate {
    return delegate;
}

- (void)setDelegate:(id <EAGLViewDelegate>)v {
    delegate = v;
}

@end