Overview

An overview of Sonolus engines.

Purpose

Engine is the driver of a level.

Engine's main responsibility is to provide behavioral logics such as drawing of gameplay elements, playing of SFX, input handling, and judging player performance. A level is then able to provide data, and combining with engine's logic it can create a full gameplay experience for players.

An engine consists of configuration, play data, watch data, preview data, tutorial data, and rom.

Configuration

Engine configuration allows players to customize the gameplay experience of a level.

Engine configuration consists of options and UI.

Options

An engine can provide a list of adjustable options for players.

These options are engine defined. Some engines may have many options to allow players to better customize their gameplay experience, while some engine may have none.

Some common options are:

• Level Speed: how fast/slow the level is being played at.
• Note Size: how big the notes are.
• Random: whether the level is randomized.

UI

UI is standardized options for UI elements.

These UI options are always available and allow engines to adjust UI based on players' input.

Play Data

Engine play data is the brain of an engine in play mode.

Engine play data consists of skin, effect, particle, archetypes, nodes, and buckets.

Skin

Skin declares which skin sprites the engine wants access to.

Effect

Effect declares which effect clips the engine wants access to.

Particle

Particle declares which particle effects the engine wants access to.

Archetypes

Archetypes are abstractions of entities.

For example, an engine may have a "tap note" archetype, which is a note needs to be tapped by players. A level can have multiple "tap note" entities all using the same "tap note" archetype, but with different entity data.

In object oriented programming, an archetype would be a class, and an entity would be an instance of a class.

Nodes

Nodes are flattened AST (abstract syntax tree) of code.

For example, an engine may have a "Add" function node with a "5" number node and a "10" number node as its arguments. When engine executes this "Add" function node, it will add the two numbers together.

In most programming languages, a node would be a syntactic token.

Buckets

Buckets are categories of playable entities.

It is optional and used by engines to provide player judgement graphs of each category at result screen.

For example, an engine may have a "tap note" bucket which shows judgment graphs of player's performance on tap notes in milliseconds, and similarly a "release note" bucket.

Watch Data

Engine watch data is the brain of an engine in watch mode.

Engine watch data consists of skin, archetypes, and nodes.

Skin

Same as play mode.

Effect

Same as play mode.

Particle

Same as play mode.

Archetypes

Same as play mode.

Nodes

Same as play mode.

Preview Data

Engine preview data is the brain of an engine in preview mode.

Engine preview data consists of skin, archetypes, and nodes.

Skin

Same as play mode.

Archetypes

Same as play mode.

Nodes

Same as play mode.

Tutorial data

Engine tutorial data is the brain of an engine in tutorial mode.

Engine tutorial data consists of skin, effect, particle, instruction, archetypes, callbacks, and nodes.

Skin

Same as play mode.

Effect

Same as play mode.

Particle

Same as play mode.

Instruction

Instruction declares which texts and icons the engine wants access to.

Callbacks

Callbacks are nodes to execute when events happen.

Nodes

Same as play mode.

Rom

Engine rom contains efficient storage and retrieval of readonly data to be used.