Re:Super Mario 64 has been decompiled
by NobodyNada on Tuesday August 27, 2019 @12:29PM
(#20811490)
> developers (incl. Nintendo themselves) often chose to rely on the OAM-object "components" of a entity as the canonical handle for tracking the entity in the game physics
I don't know how the SNES worked, but AFAIK most NES games did not track objects in this way. Instead, the game engine maintained its own buffers containing object state and copied necessary information to OAM every frame.
OAM only stored graphics state for the rendering hardware, which is not a convenient form for the game engine for a number of reasons. For instance, objects are nearly always composed of several OAM sprites placed next to each other, objects that are not visible during a given frame are not present in OAM, and a single animated object can switch between so many different graphical forms that it would be complicated to identify which object corresponds to a graphics tile from OAM. Additionally, OAM doesn't have extra room for non-graphical object state (like behavior timers or velocity information).
I don't know how the SNES worked, but AFAIK most NES games did not track objects in this way. Instead, the game engine maintained its own buffers containing object state and copied necessary information to OAM every frame.
OAM only stored graphics state for the rendering hardware, which is not a convenient form for the game engine for a number of reasons. For instance, objects are nearly always composed of several OAM sprites placed next to each other, objects that are not visible during a given frame are not present in OAM, and a single animated object can switch between so many different graphical forms that it would be complicated to identify which object corresponds to a graphics tile from OAM. Additionally, OAM doesn't have extra room for non-graphical object state (like behavior timers or velocity information).