prosperon/docs/game.md

Yugine

The yugine essentially is made of a sequence of levels. Levels can be nested, they can be streamed in, or loaded one at a time. Levels are made of levels.

Different "modes" of using the engine has unique sequences of level loading orders. Each level has an associated script file. Level loading functions call the script file, as well as the level file. The level file can be considered to be a container of objects that the associated script file can access.

• Game start

  1. Engine scripts
  2. config.js
  3. game.lvl & game.js

• Editor

  1. Engine scripts
  2. config.js
  3. editor.js

• Editor play

  • F5 debug.lvl. Used for custom debug level testing. If doesn't exist, game.lvl is loaded.
  • F6 game.lvl
  • F7 Currently edited level

Playing, editing, debugging

Playing is playing your game. Controls are what are specified for your game.

In debug builds, additional debug controls are available. For example, F12 brings up GUI debug boxes. C-M-f puts you into a flying camera mode, without pausing your game.

The game can be paused to edit it. Most editor controls are available here, all of them essentially except for loading new levels, clearing the level, etc. An object can be clicked on and edited, objects can be moved, etc.

A prefab can be opened up to edit on its own, without breaking the currently played level.

In edit mode, there are no running scripts; only editing them.

Level model

The game world is made up of objects. Levels are collections of objects. The topmost level is called "World". Objects are spawned into a specific level. If none are explicitly given, objects are spawned into World. Objects in turn are made up of components - sprites, colliders, and so on. Accessing an object might go like this:

World.level1.enemy1.sprite.path = "brick.png";

To set the image of enemy1 in level 1's sprite.

Level functions

name	description
levels	a list of all levels loaded in this one
objects	a list of all objects belonging to this level (objects + levels)
object_count	objects.length()
spawn(type)	creates an object from the supplied type in the level
create()	creates an empty level inside of this one
loadfile(file)	loads file as a level inside of this one; returns it. Mainly for editor
loadlevel(file)	loads file as a level and does running required for gameplay
load(level_json)	clears this level and spawns all objects specified in the level_json
clear()	kills all objects in this level
kill()	cleans up the level and kills it

Objects

Objects are things that exist in the game world.

name	description
level	the level this object belongs to
pos	the global position
relpos	the position relative to its level
angle	the global angle
relangle	angle relative to its level
velocity	velocity of the object
angularvelocity	angular velocity of the object
alive	true if the object is valid
varname	the variable name of the object (used for friendly naming)
friction	physics attribnute
elasticity	physics attribute
flipx	true if the object is flipped on its x axis
flipy	true if the object is mirrored on its y axis
body	the internal gameobject id of the object
controlled	true if the object is controlled by something
phys	set to dynamic; kinematic; or static; explained below
moi	the moment of inertia of the object
mass	mass of the object
visible	true if the object is visible. Set to false to disable all visible features belonging to it
in_air()	true if the object is not on the ground
on_ground()	!in_air()
layer	collision layer for the physics engine
draw_layer	draw order. higher numbers draw on top of lower ones
scale	change to make the object larger or smaller
from	the object this object was created from
boundingbox	the boundingbox of this object in world dimensions
push(vec)	push this object each frame with vec velocity
width	the boundingbox defined width
height	the boundingbox defined height
kill	destroy the object
stop	???
world2this(pos)	return the pos in world coordinates to relative this object
this2world(pos)	return the pos in this coordinates relative to the world
make(props, level)	instantiate an object based on this, with additional props, in level

Editor related object features

|gizmo| path to an image to draw in editor mode|

Functions for object control

|clone(name; ext)| create a copy of this object and extend it with ext; does not spawn| |instadup()| create an exact duplicate of this object in the World| |revert()| remove everything that makes the object unique; make it exactly like what it was spawned from|

Physics

All objects belong to the physics engine, but may be totally ignored by it.

|static| does not and will not move| |dynamic| moves under the auspices of the physics engine| |kinematic| moves under the auspices of the player or other control mechanism|

Physics properties work as such

|mass| affects how much a given force will move an object| |elasticity| affects momentum loss on collisions; multiplicative between two objects for each collision; 1 for no loss; 0 for total stoppage; >1 for a chaotic increasing entropy simulation| |friction| affects momentum loss when rubbing against another surface; multiplicative between the two objects|

Textures & images

A sprite is a display of a specific texture in the game world. The underlying texture has values associated with it, like how it should be rendered: is it a sprite, is it a texture, does it have mipmaps, etc. Textures are all file based, and are only accessed through the explicit path to their associated image file.

Finding & Addressing Objects

Editor & Debugging

Although intertwined, debugging functions and the editor are separate entities.

Debugging

Debugging functions are mapped to the F buttons, and are always available during gameplay in a debug build. Pressing the F button toggles the feature; pressing it with ALT shows a legend for that feature; pressing it with CTRL shows additional info

|F1| Draw physics info| |F3| Draw bounding boxes| |F12| Drawing gui debugging info|