void is a simple 2D engine for games and toy applications featuring:

• good typing.
• easy scripting in little code.
• fast loading.
• few dependencies.
• selective redraw for low energy idle.
• compilation to a single standalone HTML file.
• text, nine-patch, and button primitives for basic UI.
• DOM compatibility.

npm install --save @oidoid/void

• Aseprite
• cwebp

1. clone void as a sibling directory of the game.
2. npm link ../void from the game.
3. add customConditions to the root tsconfig for esbuild and a void reference for tsc. Eg:

{
  "extends": "./tsconfig.prod.json",
  "compilerOptions": {
    "customConditions": ["dev"],
  },
  "references": [{"path": "../void"}]
}

it's possible to use "paths": {"@oidoid/void": ["../void/src"]} instead of or in addition to customConditions. 4. for unit tests, run with NODE_OPTIONS=--conditions=dev.

to avoid threading template parameters throughout all code, declaration merging is used for the following:

• AnimData
• AtlasMap
• CamSchema
• CamUpdater
• Debug
• Draw
• DrawSchema
• Ent
• EntSchema
• Hook
• LevelZoo
• Loader
• PoolMap
• ReturnTag

it's similar to modifying HTMLElementTagNameMap.

populating the world usually requires defining a new ent (data type), a hook (behavior on data), a schema (level data format), and a parser (schema to ent transform). hooks are executed on ent lists ("zoos") in level loaders.

ents are plain, nonnullish, key-value data that describe game entities.

Ent is a superset of all possible key-values. use declaration merging to type. all other ents are subsets. eg, CursorEnt is {cursor: Cursor, sprite: Sprite}.

SpriteEnt is kind of a base game object that is drawable, describes bounds, and provides collision detection. if the ent should have no visual representation, leave the sprite as hidden.

the special Ent.invalid field flags whether the screen should be redrawn (which is high energy) and possibly when the hook should update. redrawing is necessary for animations but often not for static apps.

hooks are classes that process ents and usually pair to a specific ent. they're passed ents matching their query. eg, CursorHook requires at least the CursorEnt subset.

queries declare props required on an ent by a hook.

lists then ents are typically updated in insertion order. the cam and then cursor ents should appear first.

components are parsed and updated in key order. the recommended order is:

• debugInput
• id
• name
• text
• sprite
• textWH
• cursor
• hud
• ninePatch
• button
• textXY
• invalid
• override

hooks are uniquely associated with a key. zero or one hook per key. if multiple keys on an ent are associated with a hook, it will be run multiple times per update.

ents and subsystems self-report as invalid when an update or render is required. ents should avoid reading another ent's invalid state since it's cleared once that ent has been updated.

there are two schemas: a game configuration (void.json) and level configs (*.level.jsonc). the parser assumes a valid schema to minimize code size.

levels are described with the level schema. some schema components may only be applied at parse time.

there's no runtime validation.

© oidoid.

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with this program. If not, see https://www.gnu.org/licenses/.

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