openframeworks
is an addon present?
@obviousjim and I were talking about conditional includes for addon header / impl files and thought that it might be useful to suggest that all addons specify a #define that announces the addon's presence to the system. That way other addons can conditionally include bridge classes. A proposal would be something like ... in the main class ofxMyAddon.h a define like:
#define DEFINE_OFX_MYADDON
And then in the bridge classes of a dependent addon like ofxMyAddonThatDependsOnofxMyAddon.h one would do something like:
#ifdef DEFINE_OFX_MYADDON`
my special class that required OFX_MYADDON
#endif
Right now it is possible to specify required addon dependencies in addon_config.mk, but this is addressing the situation where an addon can optionally add features if an addon is present.
@arturoc @atduskgreg @bilderbuchi
Hm, is there no way we can do this automatically, e.g. during the build process generate the defines from the list of parsed addons? The make-work character of this define (i.e. have a define which basically echoes the filename) makes me feel we should be able to automate this?
The problem I see is that we have to get every addon author to add this special include, and it will be "only" useful for a subset of users, i.e. people who write addons which depend on some special functionality in another addon. It would be better if we could have a system where the dependent addon author would be the only one who would have to do something (i.e. the ifded above) to make this work for him.
Good point @bilderbuchi -- it's very easy to do with the new makefile system, but wasn't sure how it would play out in other project files. I suppose an update project generator could also take care of this.
