AreaObj: trigger zones and area effects

AreaObj objects are invisible, volume-based triggers placed in levels that activate game systems when Mario enters or stays within them. Unlike LiveActor-based objects, they do not render or participate in the physics simulation directly — they simply test whether a 3D point is inside a geometric volume, then act on the result. The AreaObj/ directory contains 36 headers covering audio, camera, environment, and gameplay areas.

AreaObj — base class

class AreaObj : public NameObj {
public:
    AreaObj(int, const char*);

    virtual void init(const JMapInfoIter&);
    virtual bool isInVolume(const TVec3f&) const;
    virtual const char* getManagerName() const;

    // Switch A/B interface
    void onSwitchA();
    void offSwitchA();
    bool isOnSwitchA() const;
    bool isOnSwitchB() const;
    bool isValidSwitchA() const;
    bool isValidSwitchB() const;

    // Follow a moving matrix (e.g. a moving platform)
    void setFollowMtx(const TPos3f*);
    TPos3f* getFollowMtx() const;

    void validate();
    void invalidate();
    void awake();
    void sleep();
    bool isValid() const;

    AreaForm* mForm;              // 0xC  — geometric volume
    int mType;                    // 0x10
    bool mIsValid;                // 0x14
    bool mIsAwake;                // 0x16
    s32 mObjArg0;                 // 0x18
    s32 mObjArg1;                 // 0x1C
    s32 mObjArg2;                 // 0x20
    s32 mObjArg3;                 // 0x24
    s32 mObjArg4;                 // 0x28
    s32 mObjArg5;                 // 0x2C
    s32 mObjArg6;                 // 0x30
    s32 mObjArg7;                 // 0x34
    StageSwitchCtrl* mSwitchCtrl; // 0x38
};

AreaObjMgr maintains a flat array of all areas of a given type and provides find_in(TVec3f) to locate the innermost area containing a point.

AreaForm — geometric volume shapes

The shape of an area is stored in an AreaForm subclass attached to mForm. The correct subclass is chosen at init time based on the object’s type parameter.

class AreaForm {
public:
    virtual void init(const JMapInfoIter&);
    virtual bool isInVolume(const TVec3f&) const;
    TPos3f* _4;  // optional follow matrix
};

// Oriented box — most common shape
class AreaFormCube : public AreaForm {
public:
    virtual void init(const JMapInfoIter&);
    virtual bool isInVolume(const TVec3f&) const;

    TVec3f mTranslation;  // 0xC
    TVec3f mRotation;     // 0x18
    TVec3f mScale;        // 0x24
    TBox3f mBounding;     // 0x30
    Mtx _48;
};

// Sphere
class AreaFormSphere : public AreaForm {
public:
    virtual bool isInVolume(const TVec3f&) const;
    TVec3f mTranslation;  // 0x8
    TVec3f mUp;           // 0x18
};

// Hemisphere / bowl
class AreaFormBowl : public AreaForm {
public:
    virtual bool isInVolume(const TVec3f&) const;
    TVec3f mTranslation;  // 0x8
    TVec3f mUp;           // 0x14
};

// Cylinder
class AreaFormCylinder : public AreaForm {
public:
    virtual bool isInVolume(const TVec3f&) const;
    TVec3f mTranslation;  // 0x8
    TVec3f mRotation;     // 0x14
};

Area categories

Audio areas

Areas that modify which sound effects or music is played while Mario is inside.

class AudioEffectArea : public AreaObj {
public:
    virtual void init(const JMapInfoIter&);
    virtual void movement();
    virtual const char* getManagerName() const;

    s32 _3C;  // effect type
    s32 _40;  // effect parameter
};

Class	Purpose
`AudioEffectArea`	Applies a reverb or echo audio effect (e.g. cave echo, underwater filter)
`BgmProhibitArea`	Suppresses background music while Mario is inside
`ChangeBgmCube`	Switches the background music track when entered
`PlayerSeArea`	Overrides the player sound effect set (e.g. switches to underwater footstep sounds)
`SoundEmitterCube`	Plays a looping environmental sound from a box-shaped source
`SoundEmitterSphere`	Plays a looping environmental sound from a sphere-shaped source

Camera areas

Areas that override, restrict, or reposition the camera system.

class CubeCameraArea : public AreaObj {
public:
    enum ECategory {
        CATEGORY_UNKNOWN_0 = 0,
        CATEGORY_UNKNOWN_1 = 1,
        CATEGORY_UNKNOWN_2 = 2,
        CATEGORY_UNKNOWN_3 = 3,
        CATEGORY_UNKNOWN_4 = 4,
    };

    virtual void init(const JMapInfoIter&);
    virtual void movement();
    virtual bool isInVolume(const TVec3f&) const;
    virtual s32 getCategoryArg() const;

    bool isValidCameraID() const;
    u16 getCameraID() const;

    static void setCurrentCategory(s32);
    static s32 sCubeCategory;

    s32 _3C;
    u32 mZoneID;  // 0x40
};

Class	Purpose
`CubeCameraArea`	Activates a named camera preset when Mario is inside the box
`CameraRepulsiveArea`	Pushes the camera away from the defined volume
`BigBubbleCameraArea`	Locks the camera for the giant bubble transport sequence
`MercatorTransformCube`	Triggers Mercator coordinate transform for 2D-style sections

Environment and visual areas

Areas that alter rendering, lighting, or post-processing while active.

Class	Purpose
`DeathArea`	Kills Mario instantly when entered; `getDeathType()` returns the death animation variant
`WaterArea`	Applies water physics to Mario; `WaterAreaMgr` manages multiple water volumes
`LightArea`	Overrides the scene lighting preset within the volume
`BloomArea`	Adjusts bloom intensity and parameters
`SimpleBloomArea`	Simplified single-parameter bloom override
`DepthOfFieldArea`	Activates or adjusts depth-of-field blur
`HazeCube`	Adds heat-haze / distortion effect
`GlaringLightArea`	Adds a lens-flare glare overlay
`ScreenBlurArea`	Applies a motion blur or Gaussian blur to the screen
`ImageEffectArea`	Generic image effect base (parent of `BloomArea`)
`SunLightArea`	Overrides sun direction and color
`QuakeEffectArea`	Activates screen-shake effect
`FollowCollisionArea`	Collision area that follows a moving actor
`CollisionArea`	Static collision trigger volume

class DeathArea : public AreaObj {
public:
    virtual void init(const JMapInfoIter&);
    virtual void movement();
    virtual bool isInVolume(const TVec3f&) const;
    virtual const char* getManagerName() const;

    s32 getDeathType() const;
};

class WaterArea : public AreaObj {
public:
    virtual void init(const JMapInfoIter&);
    s32 _3C;  // water type / behavior flags
};

class LightArea : public AreaObj {
public:
    virtual void init(const JMapInfoIter&);
    virtual const char* getManagerName() const;
    s32 mPlacedZoneID;  // 0x3C
};

Gameplay areas

Areas that control switches, warps, spin guidance, or stage transitions.

class SwitchArea : public AreaObj {
public:
    virtual void init(const JMapInfoIter&);
    virtual void movement();
    virtual const char* getManagerName() const;

    bool isUpdate() const;
};

class WarpCube : public AreaObj {
public:
    virtual void init(const JMapInfoIter&);
    virtual void movement();
    virtual void draw() const;

    JMapIdInfo* mMapIdInfo;        // 0x3C — destination map info
    ActorCameraInfo* mCameraInfo;  // 0x40 — warp camera sequence
    char* mEventName;              // 0x44
};

class SpinGuidanceArea : public AreaObj {
public:
    virtual void init(const JMapInfoIter&);
};

Class	Purpose
`SwitchArea`	Fires switch A or B while Mario is inside; deactivates when Mario leaves
`WarpCube`	Warps Mario to a different zone or galaxy section
`AstroChangeStageCube`	Triggers a stage transition when entered (used in observatory)
`SpinGuidanceArea`	Displays the spin-attack tutorial prompt when Mario first enters
`RestartCube`	Sets the respawn checkpoint used on game-over
`MessageArea`	Triggers a hint message display
`BigBubbleGoalArea`	Defines the destination for the giant bubble transport

AreaObjFollower

AreaObjFollower is a helper class that attaches an area’s volume to a moving object by calling setFollowMtx each frame, keeping the trigger volume co-located with a moving actor such as a ship or platform.

class AreaObjFollower : public NameObj {
    // Drives AreaObj::setFollowMtx every update tick
    // to make the trigger volume follow a LiveActor's matrix.
};

When reading level object placement data, an area’s mObjArg0–mObjArg7 fields carry designer-specified integer parameters that each subclass interprets independently. For example, DeathArea uses mObjArg0 as the death type index, while ChangeBgmCube uses it as the BGM track ID. Check the specific subclass init implementation to find which args are consumed.

Core Systems

Game Subsystems

Game Objects

Libraries

AreaObj: trigger zones and area effects

AreaObj — base class

AreaForm — geometric volume shapes

Area categories

AreaObjFollower

Build docs developers (and LLMs) love

Core Systems

Game Subsystems

Game Objects

Libraries

Documentation Index

​AreaObj — base class

​AreaForm — geometric volume shapes

​Area categories

​AreaObjFollower

Build docs developers (and LLMs) love

AreaObj — base class

AreaForm — geometric volume shapes

Area categories

AreaObjFollower