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Prosperon Documentation
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Getting Started
Press 'i' to see the table of contents. Press '?' for shortcuts on navigating this document!
Installation
Linux & MacOS
Install the most recent binaries into your $PATH.
Windows
Copy the executable into any folder and run it. If no game is deteced, it scaffolds for you.
Playing your first game
Download any of the completed example projects. Run prosperon play in the folder.
Poke around the example projects. You will find it refreshingly straight forward.
Engine Tour
Prosperon is built in a code-first fashion.
Scripting
The scripting language used in Prosperon is Javascript, with QuickJS. It is ES2023 compliant. It is fast, and has a number of features that make it well suited for a video game engine, like ref counting. Read more about it here.
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.
How Prosperon games are structured
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.
Prosperon games are structured into two types of source files:
- scripts
- actors
Scripts end with a return statement. A script can return a function, an object of functions, or any other sort of value.
It is a common requirement to add some amount of functionality to an object. It can be easily done with a script file.
*script.js*
function hello() { say("hello"); };
return hello;var o = {};
o.use("hello.js");
o.hello();The use function on any object loads a module, and ~assign~s its return to the object.
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.
Script entry points
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.
| script | When called |
|---|---|
| config.js | First script on Prosperon load |
| game.js | Entry point for running the game |
| editorconfig.js | Entry point for running the editor |
| predbg.js | Called before running debug |
| debug.js | Debug set up |
| dbgret.js | After stopping debug mode, used for cleanup |
Try it out. Add a script called config.js to your folder, with this.
console.log("Hello world!");
Game.quit();Run prosperon. You will see "Hello world!" in the console, and it shuts down.
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.
Actors
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 master2 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.
| fn | description |
|---|---|
| spawn(text, config) | Creates an actor as the padawan of this one, using text |
| kill() | Kills an actor |
| delay(fn, seconds) | Calls 'fn' after 'seconds' with the context of the actor |
Actor Lifetime
When an actor dies, all of the actors that have it as their master3 will die as well.
Turns
Actors get fragments of time called a turn. Actors which belong to different systems can have different lengths of turns.
Actor files
Actor files end with the extension .jso4. 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.
| function | call time |
|---|---|
| start | The first function called when the actor is in the world |
| update | Called once per turn |
| gui | Called on GUI draw |
| stop | Called when the actor is killed |
| gizmo | Called by the editor when the entity is selected |
Create a new actor, then kill it.
var act_die_call = function() {
console.log(`Actor ${this.id} has died.`);
}
var act1 = Empyrean.spawn();
var act2 = actor1.spawn();
act1.stop = act_die_call;
act2.stop = act_die_call;
Empyrean.kill(); /* Error: The Empyrean cannot be killed */
act1.kill();
act2.kill(); /* Error: act2 has been killed because act1 was */Now simplify by putting the code into a file named hello.jso.
this.stop = function() {
console.log(`Actor ${this.id} has died.`);
}Now spawn two actors using it.
var act1 = Empyrean.spawn("hello.jso");
var act2 = act1.spawn("hello.jso");Actor configuration
Actors can be created using an optional configuration file. A configuration file is one of any accepted data types. Currently, JSON or Nota. Configuration files are loaded after an actor's script file, overwriting any defined values on it.
Add a name for the actor to take on using a configuration file named hello.json.
{
"name": "Actor 1"
}Now create hello.jso to use it.
this.start = function() { console.log(`I, ${this.name}, have been created.`); }Entities
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 Primum5. 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.
In editor mode, when an entity moves, all of its padawans also move.
When the game is actively simulating, this only holds if there are physical constraints between them.
Prosperon automatically generates physical pin constraints between objects with the appropriate physical properties.
Adding Components
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.
For example, to render an image, set up a sprite component on an entity and point its path to an image on your harddrive.
var ent = Empyrean.spawn();
var spr = ent.add_component(component.sprite);
spr.path = "image.png";Put that into your config file and run prosperon. You should see the contents of "image.png" on the screen.
Try using an animated gif. Prosperon has native support for gif animations!
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.
While components can be added via scripting, it is easier to add them via the editor, as we will later see.
Ur system
The ur6 system is a prototypical inheritence system used by the actor files. When actor files are loaded, they are stored as an ur. An ur represents a set of instructions to create the (text, config) needed to spawn an actor or entity.
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.
Each ur has the following fields.
| field | description |
|---|---|
| instances | An array of instances of this ur |
| name | Name of the ur |
| text | Path to the script file |
| data | Object to write to a newly generated actor |
| proto | An object that looks like a freshly made entity from the ur |
An ur has a full path given like ur.goblin.big. goblin and big can both possibly have a .jso script as well as a data file.
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.
Prototyping Entities
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.
Entities all have the following functions to assist with this:
| function | use |
|---|---|
| clone(parent) | Create an entity prototyped from the parent |
| dup(parent) | Create an exact duplicate of the parent |
| revert() | Removes all local changes on the entity |
Speaking of practical experience, is best for ur prototype chains to be shallow.
Spawning
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.
When an entity is spawned, it is addressable directly through its master entity. Its name is generated from its file or ur type name.
Let's take a simple RPG game.
Primum
level1
orc
goblin
human
sword
uiThe 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.
| sigil | meaning |
|---|---|
| / | root of project |
| @ | root of save directory |
| # | root of link |
Resources can be referenced in a relative manner by actor scripts. When it comes to actors using assets, relative filepaths are useful and encouraged.
/
score.wav
/bumper
hit.wav
bumper.jso
/ball
hit.wav
ball.jsoPath resolution occurs during actor creation. In effect, a reference to hit.wav in bumper.jso will resolve to the absolute path /bumper/hit.wav.
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.
Caution! 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.
Links
Links can be specified using the "#" sign. These are shortcuts you can specify for large projects. Specify them in the array Resources.links.
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").
Ur auto creation
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.
Folders and files beginning with a '.' (hidden) or a '_' will be ignored for ur creation.
The folder hierarchy of your file system determines the ur prototype chain. .jso files inside of a folder will be subtyped off the folder ur name.
Only one ur of any name can be created.
@/
flipper.js
flipper/
left.js
@/
flipper/
flipper.js
left/
left.js
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
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.
/newest/
car <== When a key is pressed, this is the first pawn to handle input
player
ui <== /block/ is set to true here, so editor recieves no input!
editor
/oldest/
The default player can be obtained with Player.players[0]. Players are all local, and the highest number is determined by platform.
The input object defines a number of keys or actions, with their values being functions.
Editor input
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.
| symbol | key |
|---|---|
| C | ctrl |
| M | alt |
| S | super |
var orc = Primum.spawn(ur.orc);
orc.inputs = {};
orc.inputs.a = function() { ... };
orc.inputs.A = function() { ... }; /* This is only called with a capital A! */
orc.inputs['C-a'] = function() { ... }; /* Control-a */
Player.players[0].control(orc); /* player 0 is now in control of the orc */The input object can be modified to customize how it handles input.
| property | type | effect |
|---|---|---|
| post | function | called after any input is processed |
release_post |
function | called after any input is released |
| fallthru | bool | false if input should stop with this |
| block | bool | true if input should stop with this |
The input can be modified by setting properties on the associated function.
| property | type | effect |
|---|---|---|
| released | function | Called when the input is released |
| rep | bool | true if holding the input should repeatedly trigger it |
| down | function | called while the input is down |
GUI
Game GUIs are written by registering an entity's gui property to a function.
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.
All GUI objects derive from MUM. MUM has a list of properties, used for rendering. Mum also has functions which cause drawing to appear on the screen.
Physics
Prospeorn comes with the 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.
Editor Tour
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.
To initiate it, execute prosperon.
Editing entities
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 REPL7
The REPL lets you poke around in the game. It makes iteration and experimentation fast, fun, and easy.
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.
Easily run commands on multiple entities using Javascript functions like for each.
$.forEach(e => console.log(e.pos));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.
Playing the game
Playing the game involves running the game from a special debug.js file, or from the beginning, as if the game were packaged and shipped.
| key | action |
|---|---|
| f5 | Play the game, starting with entry point debug.js |
| f6 | Play the game from the beginning |
While playing the game, a limited editor is available that allows for simple debugging tasks.
| key | action |
|---|---|
| C-p | Pause |
| M-p | One time step |
| C-q | Quit play, return to editor |
Script Editor
Prosperon comes with an in-engine script editor. It implements a subset of emacs, and adds a few engine specific features.
Syntax coloring? … nope!
The editor that ships with Prosperon has context coloring, which is a good deal more useful than syntax coloring.
Debugging
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.
| key | description |
|---|---|
| F1 | Draw physics info |
| F3 | Draw bounding boxes |
| F12 | Draw gui info |
Exporting your game
Prosperon is a multiplatform engine. Bundling your game for these platforms essentially involves three steps:
- Baking static content
- Conversion of assets
- Packing into a CDB8
To distribute your game for a given platform, run prosperon build {platform}.
| platform |
|---|
| Linux |
| MacOS |
| Windows |
You will find your game ready to go. Rename the executable to the name of your game and run it to play. Congratulations!
Building static content
Static content creation involves any number of optimizations.
- Bitmap font creation
- Texture map creation
Creation of these assets is invisible. Prosperon updates its understanding of how to pull assets based on the existance of these packed ones.
Converting assets
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.
Packing into a CDB
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.
You can create your game's cdb by running prosperon -b. You will find a game.cdb in the root directory.
Modding & Patching
When an asset is requested in Prosperon, it is searched for in the following manner.
- The cwd9
- The game cdb (not necessarily present)
- The core 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.
Given a Prosperon-built game, you can unpack its content into a directory by running prosperon unpack {game}.
Shipping
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.
To update game to use the new patch, run prosperon patch apply {patch}, replacing patch with the name of the cdb file generated above.
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.
Mods can be distributed with the same idea.
Read-eval-print loop
I am aware of the ongoing controversy surrounding the use of this term. That is precisely why I have used it: there are a plethora of similar relationships in video games, and by using a term most teams would rather not used, I have saved left the field of avaialable ones wide open
What a mouthful!
"Javascript object".
See the Primum Mobile
A German prefix meaning primitive, original, or earliest.
Read-eval-print loop
Constant database
current working directory