Wie man UIImage aus EAGLView?

Hier ist eine gereinigte version von Quakeboy code.
Getestet habe ich es auf dem iPad und funktioniert Prima.
Zu den Verbesserungen gehören:

• funktioniert mit jeder Größe EAGLView
• arbeitet mit retina-display (Punkt-Skala 2)
• ersetzt geschachtelte Schleife mit memcpy
• bereinigt-Speicherlecks
• speichert die UIImage in das Fotoalbum als bonus.

Verwenden Sie diese Methode in Ihrer EAGLView:

-(void)snapUIImage
{
    int s = 1;
    UIScreen* screen = [ UIScreen mainScreen ];
    if ( [ screen respondsToSelector:@selector(scale) ] )
        s = (int) [ screen scale ];

    const int w = self.frame.size.width;
    const int h = self.frame.size.height;
    const NSInteger myDataLength = w * h * 4 * s * s;
    //allocate array and read pixels into it.
    GLubyte *buffer = (GLubyte *) malloc(myDataLength);
    glReadPixels(0, 0, w*s, h*s, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
    //gl renders "upside down" so swap top to bottom into new array.
    //there's gotta be a better way, but this works.
    GLubyte *buffer2 = (GLubyte *) malloc(myDataLength);
    for(int y = 0; y < h*s; y++)
    {
        memcpy( buffer2 + (h*s - 1 - y) * w * 4 * s, buffer + (y * 4 * w * s), w * 4 * s );
    }
    free(buffer); //work with the flipped buffer, so get rid of the original one.

    //make data provider with data.
    CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, buffer2, myDataLength, NULL);
    //prep the ingredients
    int bitsPerComponent = 8;
    int bitsPerPixel = 32;
    int bytesPerRow = 4 * w * s;
    CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
    CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault;
    CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
    //make the cgimage
    CGImageRef imageRef = CGImageCreate(w*s, h*s, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);
    //then make the uiimage from that
    UIImage *myImage = [ UIImage imageWithCGImage:imageRef scale:s orientation:UIImageOrientationUp ];
    UIImageWriteToSavedPhotosAlbum( myImage, nil, nil, nil );
    CGImageRelease( imageRef );
    CGDataProviderRelease(provider);
    CGColorSpaceRelease(colorSpaceRef);
    free(buffer2);
}

War ich nicht in der Lage zu Holen Sie sich die anderen Antworten hier zu arbeiten, richtig für mich.

Nach ein paar Tagen bekam ich endlich eine funktionierende Lösung für dieses. Es gibt code von Apple produziert ein UIImage aus einer EAGLView. Dann müssen Sie einfach kippen Sie das Bild vertikal da UIkit auf den Kopf.

Apple - Methode Geändert, in der Ansicht, die Sie wollen, um in ein Bild.

    -(UIImage *) drawableToCGImage 
{
GLint backingWidth2, backingHeight2;
//Bind the color renderbuffer used to render the OpenGL ES view
//If your application only creates a single color renderbuffer which is already bound at this point,
//this call is redundant, but it is needed if you're dealing with multiple renderbuffers.
//Note, replace "_colorRenderbuffer" with the actual name of the renderbuffer object defined in your class.
glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);

//Get the size of the backing CAEAGLLayer
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth2);
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight2);

NSInteger x = 0, y = 0, width2 = backingWidth2, height2 = backingHeight2;
NSInteger dataLength = width2 * height2 * 4;
GLubyte *data = (GLubyte*)malloc(dataLength * sizeof(GLubyte));

//Read pixel data from the framebuffer
glPixelStorei(GL_PACK_ALIGNMENT, 4);
glReadPixels(x, y, width2, height2, GL_RGBA, GL_UNSIGNED_BYTE, data);

//Create a CGImage with the pixel data
//If your OpenGL ES content is opaque, use kCGImageAlphaNoneSkipLast to ignore the alpha channel
//otherwise, use kCGImageAlphaPremultipliedLast
CGDataProviderRef ref = CGDataProviderCreateWithData(NULL, data, dataLength, NULL);
CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB();
CGImageRef iref = CGImageCreate(width2, height2, 8, 32, width2 * 4, colorspace, kCGBitmapByteOrder32Big | kCGImageAlphaPremultipliedLast,
                                ref, NULL, true, kCGRenderingIntentDefault);

//OpenGL ES measures data in PIXELS
//Create a graphics context with the target size measured in POINTS
NSInteger widthInPoints, heightInPoints;
if (NULL != UIGraphicsBeginImageContextWithOptions) {
    //On iOS 4 and later, use UIGraphicsBeginImageContextWithOptions to take the scale into consideration
    //Set the scale parameter to your OpenGL ES view's contentScaleFactor
    //so that you get a high-resolution snapshot when its value is greater than 1.0
    CGFloat scale = self.contentScaleFactor;
    widthInPoints = width2 / scale;
    heightInPoints = height2 / scale;
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(widthInPoints, heightInPoints), NO, scale);
}
else {
    //On iOS prior to 4, fall back to use UIGraphicsBeginImageContext
    widthInPoints = width2;
    heightInPoints = height2;
    UIGraphicsBeginImageContext(CGSizeMake(widthInPoints, heightInPoints));
}

CGContextRef cgcontext = UIGraphicsGetCurrentContext();

//UIKit coordinate system is upside down to GL/Quartz coordinate system
//Flip the CGImage by rendering it to the flipped bitmap context
//The size of the destination area is measured in POINTS
CGContextSetBlendMode(cgcontext, kCGBlendModeCopy);
CGContextDrawImage(cgcontext, CGRectMake(0.0, 0.0, widthInPoints, heightInPoints), iref);

//Retrieve the UIImage from the current context
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

//Clean up
free(data);
CFRelease(ref);
CFRelease(colorspace);
CGImageRelease(iref);

return image;

}

Und ist hier eine Methode, das Bild kippen,

- (UIImage *) flipImageVertically:(UIImage *)originalImage {
UIImageView *tempImageView = [[UIImageView alloc] initWithImage:originalImage];
UIGraphicsBeginImageContext(tempImageView.frame.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGAffineTransform flipVertical = CGAffineTransformMake(
                                                       1, 0, 0, -1, 0, tempImageView.frame.size.height
                                                       );
CGContextConcatCTM(context, flipVertical);

[tempImageView.layer renderInContext:context];

UIImage *flippedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
//[tempImageView release];

return flippedImage;

}

Und hier ist ein link auf der Apple dev Seite gefunden, wo ich die erste Methode für die Referenz.
http://developer.apple.com/library/ios/#qa/qa1704/_index.html

Mit diesem oben genannten code von Brad Larson, müssen Sie Bearbeiten Ihre EAGLView.m

- (id)initWithCoder:(NSCoder*)coder{
    self = [super initWithCoder:coder];
    if (self) {
        CAEAGLLayer *eaglLayer = (CAEAGLLayer *)self.layer;
        eaglLayer.opaque = TRUE;
        eaglLayer.drawableProperties = 
            [NSDictionary dictionaryWithObjectsAndKeys: 
                [NSNumber numberWithBool:YES],  kEAGLDrawablePropertyRetainedBacking, 
                kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat, nil];
    }
    return self;
}

Müssen Sie ändern numberWithBool Wert YES