gistfile1.m

GLvoid* load_image(NSString* imagename){
    CFURLRef url = (CFURLRef)[[NSBundle mainBundle] URLForImageResource:imagename];
    
    CGImageSourceRef source = CGImageSourceCreateWithURL(url, NULL);
    
    CGImageRef img = CGImageSourceCreateImageAtIndex(source, 0, NULL);
    
    if(!img) NSLog(@"Image loading failed for \"%@\"", imagename);
    
    NSInteger width = CGImageGetWidth(img);
    NSInteger height = CGImageGetHeight(img);
    unsigned char *data = (unsigned char*) malloc(width*height*4);
    
    // Create a context to draw the new bitmap into
    CGContextRef context = CGBitmapContextCreate(data, width, height, 8, width * 4, CGColorSpaceCreateDeviceRGB(), kCGImageAlphaPremultipliedLast);
    
    CGContextDrawImage(context, CGRectMake(0.0, 0.0, (CGFloat)width, (CGFloat)height), img);
    CGContextRelease(context);
    CGImageRelease(img);
    CFRelease(source);
    return NULL;
}