User:Deldee/objectAnatomyDraft
The following is a draft a full article on the object processes, to help debugging them for newcomers :
Rough draft, using goomba as an example:
Anatomy of an Object Code
Initialization
To start the object initialization, the object is called via a Macro preset[1] from the level script, which will prompt it initialization with the attached BehaviorScript. The BehaviorScript is then fetched in data/behavior_data.c to start initializaing the object.
Note : The following order is not consistent over the whole code. The collision data for example is loaded at different point depending on the BehaviorScript in question.
Set Object List
The first action of any BehaviorScript is to set the Object List (Or Object Groups) of an object, this categorizes the object in their processing order
Set Collision data
Scripts of the "SURFACE" object group will load their collision data. This collision data is fetched from the level structure. For example, here is the Falling Pillar collision data.
Set Object Flag
Another early action is to set the object flags of the object, these typically represent value to constantly take into account at every processing frame or high level operations to execute. For a Goomba, those are OBJ_FLAG_COMPUTE_ANGLE_TO_MARIO, OBJ_FLAG_COMPUTE_DIST_TO_MARIO, OBJ_FLAG_SET_FACE_YAW_TO_MOVE_YAW, OBJ_FLAG_UPDATE_GFX_POS_AND_ANGLE. This means that, every frame, the Goomba's Angle to Mario and Distance to Mario will be calculated and that its Yaw and graphical data will be updated
Load Animation or Model
For objects that are not part of the "SURFACE" group, the animation or model will be loaded. Animations are located in the subfolder of the object in the Actors list. As an example, for a Goomba, the animation data is located at /actors/goomba/anims
Set Object Specific Values
Set object specific values (Home, physic, drop to floor) - > src/engine/behavior_script.c
Call Native Behavior (init behavior) - > Behavior Lists
- This will also set the hitbox, which is usually a struct defined in the same file, but can be different files (boulder for example)
Begin Behavior Loop
- Call loop behavior - > Behavior Lists
End Loop