taisei-project / taisei

A free and open-source Touhou Project fangame
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Resource system partial refactor #364

Closed Akaricchi closed 1 year ago

Akaricchi commented 1 year ago

Renames some functions for consistency, but more importantly completely redesigns resource lifetime management.

RESF_PERMANENT is gone and resources are now reference-counted. Preload functions now require a ResourceGroup object that keeps references to the preloaded resources. ResourceGroups must be eventually res_group_release()'d, which decrements the refcounts of previously preloaded resources and frees memory used to store the references. Resources with zero refcount are not unloaded immediately, but put in a "purgatory" list instead. res_purge() can be called to unload all resources currently in the purgatory. Currently a purge is done right after preloading resources for a stage. This lets us keep shared resources loaded across stages, while unloading the no longer needed ones.

Resources that weren't preloaded are put into an implicit global ResourceGroup, which is never released until exit. This still generates a warning at runtime. It is possible to put resources into this global group manually without triggering the warning by passing NULL for the group pointer to res_group_preload(), but it's recommended to manage a local ResourceGroup instead.