Rex-EMoolator-docs/docs/en/reference/INERTIA.md

INERTIA

Interface to the built-in 2D physics engine of the same name (Inertia). Manages rigid bodies: creating objects, linking them to animations, gravity, velocities, damping, and applying forces. Used in Reksio i Kretes w Akcji.

Every physics body has an objectId — an integer used by most methods to identify the body. The world is loaded from an .INE file (see Engine overview) via LOAD.

Methods

ADDFORCE

void ADDFORCE(INTEGER objectId, INTEGER forceX, INTEGER forceY)

Applies a force to the object along the X and Y axes.

Parameters

• objectId — object identifier.
• forceX, forceY — force components.

Examples

EXTWORLD^ADDFORCE(1,-500,0);
EXTWORLD^ADDFORCE(1,0,-50);

CREATESPHERE

void CREATESPHERE(INTEGER objectId, INTEGER posX, INTEGER posY, INTEGER radius)

Creates a sphere of the given centre position and radius in the physics world, assigning the given identifier.

Parameters

• objectId — identifier for the new body.
• posX, posY — sphere centre position.
• radius — sphere radius.

Examples

EXTWORLD^CREATESPHERE(5,10,10,10);

DELETEBODY

void DELETEBODY(INTEGER objectId)

Removes a body from the physics engine.

Parameters

• objectId — identifier of the body to remove.

Examples

EXTWORLD^DELETEBODY(IHANDLEDEL);
EXTWORLD^DELETEBODY(IRAKIETAOBJ);

GETPOSITIONX

INTEGER GETPOSITIONX(INTEGER objectId)

Returns the body's current X position.

Parameters

• objectId — body identifier.

Returns: INTEGER — X coordinate.

GETPOSITIONY

INTEGER GETPOSITIONY(INTEGER objectId)

Returns the body's current Y position.

Parameters

• objectId — body identifier.

Returns: INTEGER — Y coordinate.

GETSPEED

DOUBLE GETSPEED(INTEGER objectId)

Returns the body's speed (linear velocity magnitude).

Parameters

• objectId — body identifier.

Returns: DOUBLE — speed value.

LINK

void LINK(INTEGER objectId, STRING animoName, BOOL flag1, BOOL flag2)

Binds a physics body to an ANIMO animation — the animation's position is updated from the physics simulation. The meaning of the two boolean flags has not been established (shipping games always pass TRUE for both).

Parameters

• objectId — physics body identifier.
• animoName — name of the ANIMO variable.
• flag1, flag2 — configuration flags (purpose not established).

Examples

EXTWORLD^LINK(1,"ANNSZCZUREK",TRUE,TRUE);
EXTWORLD^LINK(IOBIEKT,["ANNSTRZAL_"+ISTRZAL],TRUE,TRUE);

LOAD

void LOAD(STRING path)

Loads a physics-world definition from an .INE file.

Parameters

• path — path to the .INE file.

Examples

EXTWORLD^LOAD("WORLD.INE");

RESETTIMER

void RESETTIMER()

Resets the simulation's internal timer.

Examples

EXTWORLD^RESETTIMER();

SETGRAVITY

void SETGRAVITY(DOUBLE gravityX, DOUBLE gravityY)

Sets the global gravity vector. A value of (0, 0) disables gravity.

Parameters

• gravityX, gravityY — gravity components.

Examples

EXTWORLD^SETGRAVITY(0,0);

SETLINEARDAMPING

void SETLINEARDAMPING(INTEGER objectId, INTEGER linearDamping)

Sets linear damping (gradual reduction of linear velocity) for a body.

Parameters

• objectId — body identifier.
• linearDamping — damping value.

Examples

EXTWORLD^SETLINEARDAMPING(1,300);

SETMATERIAL

void SETMATERIAL(INTEGER objectId, STRING material)

Sets the body's material. Materials control how bodies respond to contact (rigidity, elasticity, friction). One name encountered in shipping scripts is "TRIGGER", for which the engine fires the ONSIGNAL^TRIGGER signal on the linked animation.

Parameters

• objectId — body identifier.
• material — material name.

Examples

EXTWORLD^SETMATERIAL(IOBIEKT,"TRIGGER");

SETPOSITION

void SETPOSITION(INTEGER objectId, INTEGER posX, INTEGER posY)

Sets the body's absolute position in the physics world.

Parameters

• objectId — body identifier.
• posX, posY — new position.

Examples

EXTWORLD^SETPOSITION(IOBIEKT,[ANNSZCZUREK^GETCENTERX()+70],[ANNSZCZUREK^GETCENTERY()-1]);
EXTWORLD^SETPOSITION(IRAKIETAOBJ,ANNDODATKI_7^GETPOSITIONX(),ANNDODATKI_7^GETPOSITIONY());

SETVELOCITY

void SETVELOCITY(INTEGER objectId, INTEGER speedX, INTEGER speedY)

Sets a body's velocity along the X and Y axes.

Parameters

• objectId — body identifier.
• speedX, speedY — velocity components.

Examples

EXTWORLD^SETVELOCITY(1,0,0);
EXTWORLD^SETVELOCITY(IOBIEKT,8,0);

TICK

void TICK()

Advances the simulation by one step. Without TICK the physics world stays frozen — typically called from a TIMER's ONTICK signal.

Examples

EXTWORLD^TICK();

UNLINK

void UNLINK(INTEGER objectId)

Breaks an animation binding established with LINK.

Parameters

• objectId — body identifier.

Examples

EXTWORLD^UNLINK(IID);
EXTWORLD^UNLINK(1);

Signals

ONINIT

Fired when the object is initialised.

ONSIGNAL

Fired when a signal arrives (see Events and signals).