CEGUI (Crazy Eddie's GUI) Forums

Hello =)

I'm working on a multlanguage application and I need to reload a set of imagesets (all of them with the same imageset name but different .png) whenever the user selects another language. To display this imagesets, in several windows I've set property "ImageNormal", "ImageHover", etc with "set:ImagesetName image:ImageName" as usual.

As far as I know, instead of doing a imageset lookup on each rendering frame, CEGUI keeps pointers to the corresponding images inside of every window. But these pointers are NOT updated whenever I do a resource reload.

I know I can "solve" this problem doing a setProperty ("Image(something)", "set..") for each window that uses a given imageset, but the time taken to traverse each window, compare imageset names etc is overkill for my app.

Is there another, more optimal solution? how could I refresh those cached image pointers?

Thanks in advance!!

so, there is no better option?

It sounds like you just want to update the underlying texture being used by the Imageset? You can do so using CEGUI::Imageset::getTexture. Then you merely update the underlying texture (by copying over the texture data you want) and then all windows using that imageset will be automatically updated. I do not think you can avoid the copy-texture step, since CEGUI::Imageset does not provide a (tmk) public method of changing the underlying texture-pointer; if you want to do that then you will need to make CEGUI::Imageset::setTexture public (and perhaps modify it's source) and then rebuild CEGUI with that change.

This sounds like something a lot of people would need, and I have used this before myself. Probably a good candidate for a feature-request, making textures in imagesets easier to update...

* edit: one caveat though with this approach is that the imagery will not be automatically updated if you are using texture-caching (AutoRenderingSurface property). In this case I think you can use System::signalRedraw, Renderer::setDisplaySize, or some such similar method to forcefully update all window imagery.

What you say is interesting, but my problem is simpler than that.. I'm just trying to load an imageset with a given name, then load a window layout that uses it (setProperty("Image", etc)), later, unload that imageset and load another imageset *with the same given name*. The point is whenever I do this, CEGUI crashes on the first rendering. It seems that there is some kind of caching or invalid pointers to the first (now unloaded) imageset and CEGUI tries to render from there although theyre wrong!

I see. I misunderstood your post; I should have read the title lol. Anyway, that does seem to be an odd crash. Can you post your CEGUI.log so we know what version, compiler, etc. you are using and perhaps there is some error message in the log? And could you also post some relevant chunks of code so that we can see how you are loading/unloading/reloading things, etc?

Have you tried calling System::signalRedraw? or Renderer::setDisplaySize? or similar API function to see if this refreshes the Imageset references?

No problem, thank you very much for your help !

I've tried signalRedraw() and friends with no luck...

Source code is pretty simple, I'm just using CEGUI::ImagesetManager::getSingleton().create () for loading imagesets, I'm doing a resource search by name whenever I want to free them:



Here is the calling stack until the point it crashes:



(at 3, d_image pointer in FalagardStaticImage is trashed...)

my app does the following:



There are no errors in the log, but you'll see I'm loading some imagesets at test/es/*, then, in my app, I clicked in the language button that in turn removes any imageset previously loaded in /test/es/* (I've a record for that) and then (as seen in the log) I'm loading imagesets in test/en/*. imagesets in test/{language} folders are basically the same xml; same imageset name, same image names, but obvously they are loading a different .png.



And that's all there is to it.. perhaps its the way I'm unloading imagesets? apart from that, this error is very easy to reproduce.. just get any CEGUI example and make it unload and reload an imageset.. if any window used that imageset, next time there is a complete redraw (ej window->invalidate(true);) it will crash. From the beginning I assumed that this is a known bug (limitation) in CEGUI by design, since I'm seeing this behaviour in cegui 0.6.x and now on each 0.7.x. but then again, perhaps I'm doing something wrong...

Thanks again!

UPDATE

I've changed my ugly imageset unload function by



Now I can actually see the image changing. Nevertheless, as stated before, it crashes on the first window->invalidate().

Any thoughts?

Yeah, I can tell you for sure that Imageset::undefineAllImages is not sufficient as it only undefines the (image-name, area) pairs associated with the imageset; the underlying texture is still preserved, and the ImagesetManager still contains the (imageset-name, object-pointer) reference.

The approach of calling ImagesetManager::destroy on each resource (or ImagesetManager::destroyAll) and then later calling ImagesetManager::create should be appropriate, as it destroys the actual Imageset object, removes the reference, and fires the appropriate events.

Alternatively, If you take a look at the parameters for ImagesetManager::create (and CEGUI::ImagesetManager::createFromImageFile) you will notice an optional parameter XMLResourceExistsAction action = XREA_RETURN I think that if you pass XREA_REPLACE this may be slightly more efficient. However, there is a note in the code here that says DANGER! so you might end up with the same problem.

I am not really familiar enough with this part of the code to answer definitively but I believe you are right in that the imageset/image references held by the windows? themselves are never updated. I have a feeling that they are merely set when initially loaded (or later via SetProperty). And there probably is no built-in mechanism for refreshing all of those references. I think that, if you want to use this method, the only option is iterating the windows and calling SetProperty :/

As mentioned in my first response, It is probably more efficient to manually load the language-specific image and then manually update (via Render to Texture) the texture underlying the imagset(s). This way you can avoid all of the headache involved with trying to update the imagset references.

CE or Kulik are more versed in this area I think and would probably be able to answer your question better, but they are pretty busy afaik :/

Exactly, the pointers are unfortunately not updated when you destroy the imageset, this should definitely be addressed. I think we could add something like a ResourcePtr that would listen to resource changes and invalidate itself when that happens or a similar solution. I would appreciate ideas about this

Jamarr wrote:Alternatively, If you take a look at the parameters for ImagesetManager::create (and CEGUI::ImagesetManager::createFromImageFile) you will notice an optional parameter XMLResourceExistsAction action = XREA_RETURN I think that if you pass XREA_REPLACE this may be slightly more efficient. However, there is a note in the code here that says DANGER! so you might end up with the same problem.

Indeed. using XREA_REPLACE thrashed the screen even more.

Eventually this issue will be fixed, but in the meantime I'd propose to change the behaviour of XREA_REPLACE to what you said: instead of a resource destroy (texture destroy/free) and a new create (this whole process won't work anyway), we could be doing an automatic texture update of the current imageset with the image specified in another imageset. Of course, this will only work if the image is exacly of the same size than the original.

What do you think? I can do (and certainly will need to do) this patch, but perhaps if this seems useful, a CEGUI guru could do this in no time?

Alternatively, is there some easy way to update the contents of a texture with an specified png?.. lets say CEGUI::Texture::loadFromFile ("image.png")? or should I open the .png, and manipulate at the pixel level?

royconejo wrote:Alternatively, is there some easy way to update the contents of a texture with an specified png?.. lets say CEGUI::Texture::loadFromFile ("image.png")? or should I open the .png, and manipulate at the pixel level?

This depends on the underlying Renderer you are using. Some of them have a Texture::loadFromFile and Texture::loadFromMemory. I know that the OpenGLTexture object has these. You can request the underlying Texture object from an Imagset via Imageset::getTexture. So in theory you should be able to 1) request the Texture from the Imageset(s) in question 2) cast the Texture to the appropriate type and 3) replace the existing image-data via one of the Texture::load* methods.