OpenGL +相机视图（iPhone）

Question

I have been 2 days trying to show an OpenGLES view over the camera View preview on the iPhone.

The camera preview alone, works. The EAGLView(OpenGLES) alone, works.

The problem is when i try to place the EAGLView over the camera preview.

I am able to place both UIViews at the same time, but the camera preview is always over the EAGLView (wrong!). When i set alpha to 0.5 of the camera preview, i can see both UIViews just as i want, but both are blurred (it's normal).

I have tried [self.view bringSubviewToFront:(EAGLView)], but nothing changes.

The EAGLView is on the IB as a class. The CameraView is added as a subview by code.

Here i put some code, i can upload more if you need it.

Thanks!!!

EAGLView

+ (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 {


    puntosPintar=(GLfloat*)malloc(sizeof(GLfloat)*8);
    puntosPintar[0] = -0.25f;
    puntosPintar[1] = -1.22f;
    puntosPintar[2] = -0.41f;
    puntosPintar[3] = 0.0f;
    puntosPintar[4] = 0.35f;
    puntosPintar[5] = -1.69f;
    puntosPintar[6] = 0.15f;
    puntosPintar[7] = 0.0f;

    if ((self = [super initWithCoder:coder])) {
        // Get the layer
        CAEAGLLayer *eaglLayer = (CAEAGLLayer *)self.layer;

        eaglLayer.opaque = NO;
        eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithBool:NO], kEAGLDrawablePropertyRetainedBacking, kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat, nil];

        context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];

        if (!context || ![EAGLContext setCurrentContext:context]) {
            [self release];
            return nil;
        }


    }
    return self;
}




- (void)drawView {
    const GLubyte squareColors[] = {
        255, 255,   0, 255,
        0,   255, 255, 255,
        0,     0,   0,   0,
        255,   0, 255, 255,
    };

    [EAGLContext setCurrentContext:context];

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
    glViewport(0, 0, backingWidth, backingHeight);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrthof(-1.0f, 1.0f, -1.5f, 1.5f, -1.0f, 1.0f);


    glMatrixMode(GL_MODELVIEW);
    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);    

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glClear(GL_COLOR_BUFFER_BIT);

    glVertexPointer(2, GL_FLOAT, 0, puntosPintar);
    glEnableClientState(GL_VERTEX_ARRAY);

    glColorPointer(4, GL_UNSIGNED_BYTE, 0, squareColors);

    glEnableClientState(GL_COLOR_ARRAY);

    glDrawArrays(GL_TRIANGLE_STRIP, 0, 8);

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

}


- (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:(CAEAGLLayer*)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;
}

UIViewController where i want to show both Load of the view of the Camera

    [CameraImageHelper startRunning];
    UIView *fafa;
    fafa= [[UIView alloc]initWithFrame:self.view.bounds]; //returns a UIView with the cameraview as a layer of that view. It works well (checked)
    fafa = [CameraImageHelper previewWithBounds:self.view.bounds];
    fafa.alpha=0.5;  //Only way to show both
    [self.view addSubview:fafa];
    [self.view bringSubviewToFront:fafa];

Load of the EAGLView On the .hi have created

IBOutlet EAGLView *openGLVista

In the view did load:

openGLVista=[[EAGLView alloc]init];

CameraImageHelper.h

@interface CameraImageHelper : NSObject <AVCaptureVideoDataOutputSampleBufferDelegate>
{
    AVCaptureSession *session;
}
@property (retain) AVCaptureSession *session;

+ (void) startRunning;
+ (void) stopRunning;

+ (UIView *) previewWithBounds: (CGRect) bounds;
@end

CameraImageHelper.m

- (void) initialize
{
    NSError *error;
    AVCaptureDeviceInput *captureInput = [AVCaptureDeviceInput deviceInputWithDevice:[AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo] error:&error];
    if (!captureInput)
    {
        NSLog(@"Error: %@", error);
        return;
    }


    self.session = [[[AVCaptureSession alloc] init] autorelease];
    [self.session addInput:captureInput];
}

- (id) init
{
    if (self = [super init]) [self initialize];
    return self;
}

- (UIView *) previewWithBounds: (CGRect) bounds
{
    UIView *view = [[[UIView alloc] initWithFrame:bounds] autorelease];

    AVCaptureVideoPreviewLayer *preview = [AVCaptureVideoPreviewLayer layerWithSession: self.session];
    preview.frame = bounds;
    preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
    [view.layer addSublayer: preview];

    return view;
}

- (void) dealloc
{
    self.session = nil;
    [super dealloc];
}

#pragma mark Class Interface

+ (id) sharedInstance // private
{
    if(!sharedInstance) sharedInstance = [[self alloc] init];
    return sharedInstance;
}

+ (void) startRunning
{
    [[[self sharedInstance] session] startRunning]; 
}

+ (void) stopRunning
{
    [[[self sharedInstance] session] stopRunning];
}


+ (UIView *) previewWithBounds: (CGRect) bounds
{
    return [[self sharedInstance] previewWithBounds: (CGRect) bounds];
}

@end

Answer 1

I see that in IB you are using the EAGLView as the view of the view controller, and in the code snippet you add the preview view as a subview of that view. In other words, your view hierarchy looks something like this:

*- EAGLView
    +- Preview view

Thus, Preview view is always on top of the EAGLView because it is a subview of the EAGLView. If you want to be able to display either one on top of the other, you will instead have to lay things out like this:

*- some generic UIView
    +- EAGLView
    +- Preview view

In other words, in IB you should have a generic UIView bound to the view property, and then drag the EAGLView so it is inside that generic UIView. Then your code for adding the preview view should work right.

---

BTW, this does not do what you seem to think:

fafa= [[UIView alloc]initWithFrame:self.view.bounds]; //returns a UIView with the cameraview as a layer of that view. It works well (checked)
fafa = [CameraImageHelper previewWithBounds:self.view.bounds];

The first line creates a generic UIView. Then the second throws it away (leaking the memory!), replacing it with the preview view. You should just delete the first line.