portal64-still-alive/documentation/levels/level_objects

Level Objects

Objects can be placed in a level via their associated .blend and .yaml files, causing them to be rendered and animated properly by the game at the correct position/orientation and with the correct materials applied.

However, the game needs to be able to give each object the proper behavior. Buttons activate specific doors, triggers start relevant cutscenes, the floor stops the player from falling through, and so on.

Naming convention

At level export time, level definition C source files are generated using the Lua scripts in tools/level_scripts/, initiated by export_level.lua. The way the level exporter knows how to properly populate these definitions with objects is by using their names. Every object in a level's .blend file has a name of the form:

@TYPE [ARG]...

That is, an @-prefixed type name followed by 0 or more space-separated arguments. The number and type of the arguments is object type specific.

This could have been done with Blender's custom object properties feature, but one nice benefit of this approach is that it makes searching for related objects easy.

Object types

See the linked pages below for details on specific level objects.

Type	Description
@ambient	Ambient light source for baked lighting
@anim	Animatable armature bone
@ball_catcher	High energy pellet receptacle
@ball_launcher	High energy pellet spawner
@box_dropper	Cube spawner
@button	Flat, circular button
@clock	Countdown clock
@collision	Static collision
@decor	Generic dynamic object
@door	Sliding door
@doorway	Level segment connection for rendering and collision
@dynamic_box	Dynamic collision
@elevator	Level transition elevator
@fizzler	Emancipation grill
@location	Referenceable point in the world
@pedestal	Portal gun holder
@point_light	Omnidirectional light source for baked lighting
@room	Discrete level segment for rendering and collision
@security_camera	Wall-mounted camera
@signage	Start of level informational sign
@static	Static geometry
@switch	Button on pedestal
@trigger	Signal and cutscene activating volume