iPhone - Image created with CGBitmapContextCreate as Opengl texture

Question

I want to call CGBitmapContextCreate with texture->data to create a CGContextRef, and create a CGImageRef by CGBitmapContextCreateImage(context).

However, the image created is not as expected :(

The one created from CGBitmapContextCreateImage:

The actual one (slight different since I take it with another camera):

Codes: (texture.bytesPerPixel = 2)

    CGContextRef context = CGBitmapContextCreate(texture.data, 512, 512, 5, 512 * texture.bytesPerPixel, CGColorSpaceCreateDeviceRGB(), kCGImageAlphaNoneSkipFirst);
    CGImageRef cg_img = CGBitmapContextCreateImage(context);
    UIImage* ui_img = [UIImage imageWithCGImage: cg_img];
    UIImageWriteToSavedPhotosAlbum(ui_img, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);

Complete Code:

http://ihome.ust.hk/~tm_lksac/OpenGLSprite.m

The application usually calls - (void)drawSelfIfNeeded:(BOOL)needed to update the texture in the application. But I want to take a "screenshoot" of the texture and save it as UIImage as further image processing.