pogp

v0.2.74

Published

a year ago

The POG Protocol for game development defines a portable game loop and language-neutral binary representations of Inputs and State.

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neilsarkar

Portable Open Game Protocol 0.0.19

Making games should feel like playing games.

Introducing the POG protocol

The POG Protocol defines language-neutral binary representations of Inputs and State.

This allows us to create a portable game loop that can be run in browser or any major game engine.

Portable

browser - use wasm to prototype and playtest with hot reloading
standalone / mobile / console - use ffi to bring your game loop into any game engine
online multiplayer - run your game loop on any web server or exchange pogp binary input peer to peer

Open

input representations are based on web standards
state representations use open standards (WIP)
games that adopt the protocol can benefit from shared solutions for common functionality

Game

immersion during the development process is sacrosanct. making games feels like playing games.
the POG protocol is designed to be zero-copy, zero-alloc per frame
you can continue to use and benefit from all the great game making tools and rendering you use today for mobile, browser, standalone and console targets

Goals

The goal of the POG protocol is to help create better games for players, to make game development more accessible, and to reduce crunch.

The goal is for anyone familiar with basic software development to create a game using the protocol today, using the languages and tools they're already familiar with.

Web and app developers benefit from industry-wide adoption of open technology like the HTTP protocol and Linux.

Game developers have typically suffered from a more closed source mindset, with many shared solutions for crucial low-level problems locked behind paywalls or other privileged access.

I love games, and I believe that by embracing open standards and shared solutions across languages and game engines, there can be a better world for developers and players of games.

Code Example (typescript/browser)

import { GameLoop, MarshalInput, KeyboardSnapshot } from 'pogp';

const keyboard = new KeyboardSnapshot();
const heroElement = document.body.appendChild('div') as HTMLElement;

let state = {
	hero: { x: 0, y: 0 }
};

new GameLoop((frame, now, inputs) => {
	// read inputs from binary buffer
	keyboard.addInput(MarshalInput.decodeKeyboard(inputs));

	// run update loop
	if (keyboard.isKeyDown(Key.KeyD)) {
		state.hero.x += 10;
	} else if (keyboard.isKeyDown(Key.KeyA)) {
		state.hero.x -= 10;
	}

	// render to screen
	heroElement.style.transform = `translateX(${state.hero.x}px)`;
})

Interactive Examples

Pong

https://pogprotocol.com

Project Status

The Pog Protocol is in a pre-alpha state. The protocol itself is still being defined, and client libraries currently only exist for rust.

We are looking for domain experts to contribute to libraries for each major game engine and runtime environment.

If you are interested in contributing or adding an environment to the list, please open a github issue or drop me a line on discord nu11#1111 or neil at nullent.com

Path to 1.0

Define state protocol
Define rendering protocol
Flesh out existing libraries
- rust
- typescript
- unity c#
Add client libraries
- c++
- modern c#
Add online multiplayer demo
- in browser
- in a game engine
Add engine demos beyond unity
- unreal engine
- godot
- bevy

Client Libraries

Game Logic Client Libraries

Rendering Client Libraries

Contributors:

@ns - @neilsarkar

Reference

Inputs

Inputs contain the state of the input at the current frame.

Whenever possible, representations are based on open standards.

Gamepad (a.k.a. Controller) Input

Touch Input

Mouse Input

Keyboard Input

Gamepad Input

Gamepad input represents what's commonly called a "Controller".

We extend the open standard https://developer.mozilla.org/en-US/docs/Web/API/Gamepad with a standard for generic positional identifiers.

JSON Schema | JSON Example

Binary Schema | Binary Example

Gamepad JSON Schema

type

This will be an Input Type set to gamepad

The Gamepad.id of the gamepad

vendorId

The vendor id of the gamepad.

productId

The product id of the gamepad.

vendorName

A human readable name for the vendor, e.g. Nintendo, Microsoft, Sony etc

productName

A human readable name for the product, e.g. Left joy-con, Xbox Series S, Dualshock 5

buttons

An array of Button states
- label
  - the text printed on the button, e.g. Triangle, A, ZR
- value
  - int representing the percentage depressed with four digits of precision
- touched
  - boolean representing whether button is touched
- position
  - string enum representing button position , e.g. left-face-top, right-shoulder-front

axes

An array of Axes states
- hand
  - string enum representing hand intended to be used with joystick: left | right | unknown
- value
  - an array of two signed longs representing the x and y position of the thumbstick

Gamepad JSON Example

{
	type: 'Gamepad',
	id: 'Stadia Controller rev. A (STANDARD GAMEPAD Vendor: 18d1 Product: 9400)'
	vendorName: "Google",
	productName: "Stadia",

	buttons: [
		{
			label: 'A',
			position: 'right-face-bottom',
			value: 100000 // 100%
		},
		{
			label: 'B',
			position: 'right-face-right',
			value: 500600 // 50.06%
		},
		{
			label: 'X',
			position: 'right-face-left',
			touched: true,
			value: 0
		},
		{
			label: 'Y',
			position: 'right-face-top',
			value: 0
		},
		{
			label: 'L1',
			position: 'left-shoulder-front',
			value: 0
		},
		{
			label: 'L2',
			position: 'left-shoulder-back',
			value: 0
		},
		// ...
	],
	axes: [
		{
			hand: 'left',
			value: [
				0n, // x-axis idle
				2147483647n // y-axis max up
			]
		},
		{
			hand: 'right',
			value: [
				-2147483647, // x-axis full left
				-2147483647  // y-axis full down
			]
		}
	],
}

Gamepad Binary Schema

Gamepad Button Binary Schema

data | example | type | index | length (bytes) |-|-|-|-|-| position | 2 | byte (ButtonPosition) | 0 | 1 value | 100000 | uint32 | 1 | 4 label | "A" | string | 5 | 64

Gamepad Axes Binary Schema

data | example | type | index | length (bytes) |-|-|-|-|-| hand | 1 | byte (Hand) | 0 | 1 x | 100000 | int64 | 1 | 64 y | 100000 | int64 | 65 | 64

Keyboard Input

Keyboard keys are represented using the w3 standard, supporting standard 101, Korean, Brazilian and Japanese keyboards.

https://www.toptal.com/developers/keycode

https://www.w3.org/TR/uievents-code/#keyboard-mac

{
       type: "keyboard",
       keys: [
               27,
               65
       ]
}

Touch Input (WIP)

{
	type: "touch",
	resolution: [0,0],
	fingers: [
		// there will always be at least one element
		{
			position: [0,0],
			pressure: 0
		}
	]
}

Mouse Input (WIP)

{
	type: "mouse",
	resolution: [1920, 1080],
	position: [100, 100],
	buttons: [
		{
			id: 'left',
			down: true
		},
		{
			id :'right',
			down: false
		},
	],
	wheels: [
		{
			id: 'scroll',
			delta: [0,20,0]
		}
	]
}

Custom (WIP)

{
	type: "custom",
	id: 'my-flightstick',
	fields: [
		{
			id: 'whammybar',
			values: [420,69]
		},
		{
			id: 'something',
			values: [0]
		}
	]
}

State (WIP)

Game state represents the state of the game. This is going to be custom for each game.

int is short for int32

{
	// this is the pog protocol major version
	pog: 0,
	// this is the pog protocol minor version
	pogMinorVersion: 1

	// these are the members of the state.
	fields: {
		// primitives
		timeLeft: 'int',

		// objects defined below
		player: 'player',
		level: 'level',

		// arrays of primitives or objects
		enemy: ['enemy'],

		// dictionaries of primitives or objects
		levelClearTimes: {
			int: 'int'
		},
		levelsById: {
			int: 'level'
		}
	},

	// these are objects defined by the game
	objects: [
		player: {
			position: 'vector2',
			score: 'int',
			jump: 'bool',
			myIntList: ['int'],
		}
		enemy: {
			position: 'vector2',
			health: 'int',
		},
		level: {
			id: 'int',
			tiles: ['tile']
		},
		tile: {
			position: 'vector2',
			type: 'int'
		}
	],
}

The json state will exist in both the logic and the renderer, so object structures are not shared, only the values

data | example | type | index | length (bytes) |-|-|-|-|-| pog major version | 0 | int | 0 | 4 pog minor version | 1 | int | 4 | 4

* fields are done alphabetically

* vectors and fixed length structs are inline

* arrays, lists and dictionaries are represented as an integer of their total length

* array, list and dictionary reading happens after reading the primitives in the state

* strings are utf32 encoded

tic tac toe example:

{
	// 0 is not taken, 1 is X 2 is O
	board: [
		0, 0, 0,
		0, 2, 0
		1, 0, 0
	]
}

// fields
uint 9  // length of array

// arrays, lists and dictionaries
ubyte 0 // top left
ubyte 0 // top middle
ubyte 0 // top right
ubyte 0 // middle left
ubyte 2 // middle middle
ubyte 1 // bottom left
ubyte 0 // bottom middle
ubyte 0 // bottom right

pong example:

{
	isGameOver: false,
	player1: {
		position: [0, 100],
		score: 1
	}
	player2: {
		position: [100,-100],
		score: 0
	},
	ball: {
		position: [50, 50]
	}
}

Client libraries:

(json schema) => file of native object

(binary data, json schema) => native object

(native object, json schema) => binary data

e.g. csharp

public static string StateFile(string json, string path) {
	// outputs a .cs file to path that has the structure of the json file
}

Button Position Enum

Input Type Enum

Hand Enum

Key Enum

Published

Vulnerabilities

Links

Maintainers

Keywords

Readme

Portable Open Game Protocol 0.0.19

Introducing the POG protocol

Portable

Open

Game

Goals

Code Example (typescript/browser)

Interactive Examples

Project Status

Path to 1.0

Client Libraries

Reference

Inputs

Gamepad Input

Gamepad JSON Schema

Gamepad JSON Example

Gamepad Binary Schema

Gamepad Button Binary Schema

Gamepad Axes Binary Schema

Keyboard Input

Touch Input (WIP)

Mouse Input (WIP)

State (WIP)

Button Position Enum

Input Type Enum

Hand Enum

Key Enum