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Oak Nut engine.

Commonly called “onut”. Game engine focused on rapid development. Aimed at Game Jams.

Quick javascript sample

Load image and draw a sprite

var texture = getTexture("image.png");

function render() {
    // Begin a batch
    SpriteBatch.begin();
    
    // Draw a sprite at screen coordinates x=200, y=100 from top left corner.
    SpriteBatch.drawSprite(texture, new Vector2(200, 100));
    
    // End and flush the batch
    SpriteBatch.end();
}

Update loop

function update(dt) {
    spriteAngle += dt * 45; // Will rotate 45 degree per second
}

function render() {
    ...
    
    // Draw a sprite at with an animated angle
    SpriteBatch.drawSprite(texture, new Vector2(200, 100), Color.WHITE, spriteAngle);
    
    ...
}

See onut/samplesJS/ folders for more detailed samples.

Overview

List of projects using it:

Arctic Distress

Click to Repair

Eagle's Nest

Messenger Hacker

Retro Game War

Spy Satellite Showdown

Fire Whisperers

Cannon Fodder Commander

Release history

JavaScript Game

Compile the executable

  1. Clone onut somewhere on your PC.
  2. Generate using cmake.
  3. Build the JSStandAlone project in release.
  4. Copy the executable to your game’s folder.

Setting up your JavaScript project

Recommended to use Visual Studio Code.

  1. Create a folder for your game somehere on your PC
  2. Copy [onut path]/jsconfig.json, [onut path]/typings/onut.d.ts to YourGame path.
  3. Create a settings.txt file. Refer to samples to see what can be put in there.
  4. Create assets and javascript files
  5. main.js will always be the last JavaScript file executed, use it to initialize stuff.

main.js

function update(dt) {
    // Update your game here
}

function render() {
}

C++ game

Before you start. Please take note of the following folder structure. It is highly recommended for minimal setup time. The default asset search paths are configured for this structure. But it easy to add more using oContentManager->addSearchPath.

main.cpp

Make sure to define those 6 functions. Otherwise you will get unresolved errors.

void initSettings()
{
    // Set Default game settings can be set using oSettings.
}

void init()
{
    // Load your content.
}

void shutdown()
{
    // Cleanup.
}

void update()
{
    // Game logic.
}

void render()
{
    // Game render.
}

void postRender()
{
    // Render more stuff after post process.
}

void renderUI()
{
    // Draw imgui debug UI.
}

Look at samples to see what can be done here.

Specific usages

SpriteAnim

Sprite anims can be edited in Aseprite and exported as json. Certain flags can be set on frame’s properties. Properties are colon “:” separated.

i.e.: “loop:genfliph:next=idle

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Frame properties and their meaning:

name usage scope meaning
loop loop tag animation will be looped
genfliph genfliph tag an extra animation will be created with the name tag+”_fliph”, flipped horitontally
genflipv genflipv tag an extra animation will be created with the name tag+”_fliph”, flipped vertically
next next=tagName tag when this animation is finished, it will trigger tagName
origin origin=x,y frame set frame origin. This will apply to subsequent frames until the next origin.
sound sound=step.wav frame plays a sound on this frame
soundcue soundcue=step.cue frame plays a sound cue on this frame
vol vol=0.5 frame set volume for sound [0, 1].
pan pan=0.0 frame set panning for sound [-1, 1].
pitch pitch=2.0 frame set pitch for sound.

When exporting the sprite sheet in json format, make sure to change “Hash” to “Array”.

Mentions

Logo design by Pixilabs Software Inc.