SDK: Get total number of scenes and max length of a scene name

djinoui

Hello Mark and Isadora developers,

I'm rewriting dbengali's plugin JumpByName ([http://troikatronix.com/troikatronixforum/discussion/768](http://troikatronix.com/troikatronixforum/discussion/768)) as I'd like to use it on Windows.

The way I proceed is quite simple:

browse all scenes in a 'for' loop
if the name of the currently requested scene (I use the GetSceneName_ function defined in IsadoraCallbacks.h) matches the requirements according to the parameters, jump to this scene

But this approach raises 2 problems:

The 'for' loop needs a boundary. For now I hardcoded it in a constant, assuming that no Isadora project would use more than, say, 2000 scenes.
The GetSceneName_ function requires a maxLen parameter, which seems to be the size of the string it fills with the scene name. I also used a constant, assuming that no one would have a scene name of 1000 characters.

I would like the performance to be optimal, not to mention the ugliness of these solutions. Hence these 2 questions:

Is there a way to get the total number of scenes in an Isadora project dynamically (something like GetNumberOfScenes_ ?), or at least the maximum size of the scene array (if it's not dynamically assigned) ?
Same question for the size of the scene name string (a constant maybe?)

Thanks in advance.

djinoui

Just a little update. I finally managed to solve problem #1, I just replaced the 'for' loop with a do/while: knowing that GetSceneName_ fills the string parameter back with empty content (""), it can be tested as a loop end condition.

char loopCurrentSceneName[SCENE_NAME_MAX_LENGTH];

int i = 1; // scene index (one-based)

do

{

GetSceneName_(ip, inActorInfo, mode, i, SCENE_NAME_MAX_LENGTH-1, loopCurrentSceneName); // loopCurrentSceneName pointer now points to the scene name at current index

...

i++;

}while (strcmp(loopCurrentSceneName, "") != 0); // Loop while a scene name is found in scene list

As you can see, I didn't solve problem #2 (kept the SCENE_NAME_MAX_LENGTH constant defined in linked .h file), but after all it's no big deal.

DusX

Cool.. the name length is not such an issue..
thanks for putting in the hard work.

dbengali

Sorry again to disappear while you were working on this and not to save you time!

For #2 I made a similar choice, though I set the max length to 128\. I believe I left a warning in the actor help about keeping scene labels less than 128 characters. You were more generous :)

For #1 I also wonder if there is a way to find out the number of scenes somewhere, but I assumed that the scene list is maybe stored internally as a linked list rather than an array, in which case, there isn't necessarily a way to know the number of scenes other than navigating the list. So, while iterating through the scenes looking for the search string, I just catch the error "kIzzyErr_SceneDoesntExist" to know if I have run past the end of the scene list, and thus can stop checking. This conveniently avoids the need for a constant boundary on number of scenes.

hope this helps, even though it is a bit late.

djinoui

No problem, dbengali, thanks for your post anyway. The try/catch approach is interesting too, seems more robust in case of a change in the API.

djinoui

Oh... I see. No try/catch, just the return value compared to the kIzzyErr_SceneDoesntExist constant.

I'm feeling lazy to adapt my source right now, I'll keep the empty string comparison for now... works well too.