Javascript is used here mostly to set up objects and tear them down. Although computationally expensive tasks can be done using QuickJS, Prosperon makes it easy to extend with raw C.
Prosperon schews the CommonJS and ES module systems for a custom one suitable for a computer game actor model. It is more restricted than either system, while retaining their full power.
Scripts are loaded into memory only once. Further `use` statements only generate references to the statements. Because *scripts* are executed in a lambda environment, any `var` declared inside the script files are effectively private variables, persistent variables.
In a *script*, `this` refers to `undefined`. It is nothng.
In an *actor* source file, `this` refers to the actor. Actors do not end in a `return` statement. *actor* source is intended to set up a new agent in your game. Set up the new entity by loading modules and assigning functions to `this`.
The first way you can customize Prosperon is by adding scripts to the folder you're running it from. Any file ending with *.js* is a *script* which can be ran by Prosperon.
Using `config.js` and `game.js`, you can write an entire game, without reaching any further. When you want to populate a world with independent actors, entities are what you will reach for.
The fundamental tool for building in Prosperon is the actor system. Actors run independently from each other. Actors are defined by a combination of code and data. All actors have a *master* which controls certain properties of the actor.
The most masterful actor is the *Empyrean*. The first actor you create will have the Empyrean as its master. Subsequent actors can use any other actor as its master.
Actor files end with the extension *.jso*[fn::"Javascript object".]. They list a series of functions to call on a newly formed actor. Actors have a number of useful functions which are called as defined.
Actors can be created using an optional configuration file. A configuration file is one of any accepted data types. Currently, JSON or [[https://www.crockford.com/nota.html][Nota]]. Configuration files are loaded after an actor's script file, overwriting any defined values on it.
Game worlds are made of entities. Entities are a type of actor with a number of useful properties. Entities can only be created on the actor named *Primum*[fn::See the Primum Mobile]. The Primum is the outermost actor with a physical space. While Actors are more abstract, Entities exist in a definite space, with a position, rotation, and so on. Entities can respond to physics and play sounds. Anything which can be thought of as having a position in space should be an entitiy.
The first and most masterful entity is the Primum. The Primum has no components, and its rotation and position are zero. It defines the center of the game.
Entities can have *components*. Components are essentially javascript wrappers over C code into the engine. Scripting is done to set the components up on entities, after which most of the work is done by the C plugin.
Components only work in the context of an entity. They have no meaning outside of a physical object in the world. They have no inherent scripting capabilities.
The ur[fn::A German prefix meaning primitive, original, or earliest.] system is a prototypical inheritence system used by the actor files. When actor files are loaded, they are stored as an ur. An *ur* holds a list of (text, config) required to create an entity.
When prosperon starts, it searches for urs by name. Any file ending in ".jso" or ".json" will be interpereted as an ur, with same named jso and json being applied as (text, config) for an ur. A jso or json alone also constitute an ur.
An ur can also be defined by a json file. If an ur is found, it takes predecent over auto generated urs. The json of an ur looks like this:
| field | description |
|----|----|
| text | Path to a script file, or array of script files, to apply to the object |
| data | Path to a json file, or array of json files, to apply to the object |
Any ur file with this sort of json creates an ur which can be created in the game. A file named "box.ur" will be ingested and be available as "ur.box". When saving differences, it creates a json file with the same name as an ur (in this case, "box.json").
Create an ur from the *hello* files above, and then spawn it.
```
ur.create("hello", "hello.jso", "hello.json");
Primum.spawn(ur.hello);
```
When creating an actor from source files, all of its setup must take place. In this example, the setup happens during *ur.create*, and spawning is simply a matter of prototyping it.
Objects can be composed on the fly by stringing together urs. For example, a "2x.json" might define scale as 2x. Then, you can create a goblin with `ur.goblin`, or a large goblin with `ur.goblin.2x`. This creates a goblin object, and then applies the 2x scripts and jsons onto the object.
When `goblin.big` is created, the new object has the `goblin` script run on it, followed by the `big` script. The `data` fields consist of objects prototyped from each other, so that the `__proto__` of `big.data` is `goblin.data`. All fields of this objects are assigned to the `big goblin`.
The unaltered form of every ur-based-entity is saved in the ur's `proto` field. As you edit objects, the differences between how your object is now, compared to its `ur.proto` is a list of differences. These differences can be rolled into the `ur`, or saved as a subtype.
Ur types are the prototype of created entities. This makes it trivial to change huge swathes of the game, or make tiny adjustments to single objects, in a natural and intuitive way. When a value is changed on an entity, it is private. When a value is changed on an ur, it propogates to all entities. Values cannot be added or removed in subtypes.
Actor data and ur types can remember which entities were contained in it when saving. They are stored in the *objects* field. When an entity with an *objects* field is spawned, it spawns all of the objects listed in turn.
The orc, for example, is addressable by `Primum.level1.orc`. The `human` has a `sword` spawned underneath it. When he is killed, his sword also disappears.
### Resources
Assets can generally be used simply with their filename. Assets can be modified with a sidecar file named *filename.asset*, so, a file `ball.png` can have additional parameters through its `ball.png.asset` file.
If the asset is not found, it is searched for until the project root is reached. The bumper can reference *score.wav* and have the path resolution take place. Later, if the it is decided for the bumper to have a unique score sound, a new /score.wav/ can be placed in its folder and it will work without changing any code.
Because the path is resolved during object load, you will need to fresh the bumper's ur or spawn a new bumper for it to use the newly placed /score.wav/.
An example is of the form `trees:/world/assets/nature/trees`. Links are called with `#`, so you can now make a "fern" with `Primum.spawn("#trees/fern.jso")`.
Instead of coding all the ur type creation by hand, Prosperon can automatically search your project's folder and create the ur types for you. Any /[name].jso/ file is converted into an ur with the name. Any /[name].json/ file is then applied over it, should it exist. If there is a /.json/ file without a corresponding /.jso/, it can still be turned into an ur, if it is a valid ur format.
`prototypes.generate_ur(path)` will generate all ur-types for a given path. You can preload specific levels this way, or the entire game using `prototypes.generate_ur('.')`. If your game is small enough, this can have a massive runtime improvement.
Input is done in a highly generic and customizable manner. *players* can take control of any object (actor or otherwise) in Prosperon, after which it is referred to as a *pawn* of a player. If the object has a defined *input* object, it is a valid pawn. One player can have many pawns, but each pawn may have only one player.
Pawns are added as a stack, with the newest ones getting priority, and handled first. It is possible for pawns to block input to lower pawns on the stack.
The editor input style defines keystrokes. It is good for custom editors, or any sort of game that requires many hotkeys. Keystrokes are case sensitive and can be augmented with auxiliary keys.
The GUI system which ships with Prosperon is called *MUM*. MUM is a declarative, immediate mode interface system. Immediate to eliminate the issue of data synchronization in the game.
Prospeorn comes with the [[https://chipmunk-physics.net][Chipmunk]] physics engine built in. It is a fast, stable physics solution. All entities are assumed to be physics based objects, and components can be added to them to enable more physics features.
Prosperon's visual editor is an assistant for the creation and editing of your game entities and actors. In the editor, all ur types are loaded, and assets are constantly monitored for changes for hot reloading.
The desktop is the topmost entity that exists in the editor. Instead of editing specific files, you simply load them into your desktop, and go from there. This makes it easier to see two different entities simultaneously so you can ensure changes to one are congruous with the vision for the others.
The main editor view is made up of entities. Each entity can have a number of components attached to it. When an entity is selected, its name, position, and list of components are listed.
Basic use of the editor involves spawning new entities, or ones from already made ur types, editing them, and then saving them as new ur types or overwriting the ones they spawned from. Specific tools have been written to make editing components and levels easier than with a text editor, and the editor is easily extendable for your own purposes.
Assign the entity's *gizmo* property to a function to have that function called each gui rendering frame.
The symbol `$` references the current REPL entity. If no entity is selected, the REPL entity is the currently edited one. Otherwise, it is the selected entity, or group of entities, as an array.
The REPL is a powerful tool for editing your game. Arbitrary code can be ran in it, meaning any esoteric activity you need done for your game can be done easily. Commonly used functions should be copied into your /editorconfig.js/ to be called and used at will.
Debugging functions are mapped to the F buttons, and are available in any debug build of the game. Pressing the specified key toggles the feature; pressing it with /alt/ shows a legend for that feature.
Images, videos, and sounds, are converted to assets most suitable for the target platform. This may be for speed or simple compatability. *You do not need to do anything*. Use your preferred asset types during production.
A *cdb* is known as a "constant database". It is a write once type of database, with extremely fast retrieval times. Packing your game into a cdb means to create a database with key:value pairs of the filenames of your game. The Prosperon executable is already packed with a core cdb. Your game assets are packed alongside it as the game cdb.
Game modification is trivial using this described system. By putting an asset in the same path as the asset's location in the game cdb, when that asset is requested it will be pulled from the file system instead of the game cdb.
Once a game's assets are modified, it may be desirable to ship them. Run `prosperon patch create {game}` to create a /patch.cdb/ filled only with the files that are different compared to those found in the /game.cdb/ in the /game/.
Many patches can be bundled by running `prosperon patch bundle {list of patches}`. This creates a patch that will update the game as if the user had updated each patch in order.
