/Cocoa

A general-purposed 2D rendering framework & visual novel engine.

Primary LanguageC++GNU General Public License v3.0GPL-3.0

Project Logo

JavaScript Engine for 2D Rendering on Linux

This project belongs to OpenACG Group.

わたしわ、高性能ですから！

Documentations

Motivation & Introduction

Cocoa is a project inspired by ATRI -My Dear Moments-, initially aiming to improve the VN experience on the Linux platform and provide a framework for those who are interested in VN creation. Although Cocoa is initially created for VN, it is completely a general-purposed 2D rendering framework that can fit other similar situations.

The project name Cocoa comes from an anime called Is the Order a Rabbit? which has a heroine named Kokoa Hoto. So its pronunciation is actually follows the Japanese Katakana ココア. But it also doesn't matter much if you pronounce it in English way.

TypeScript is the official programming language of Cocoa. Cocoa itself can be treated as a JavaScript engine, which is written in C++17. Rendering framework part of Cocoa is mostly built by native C++, while the visual novel framework part is completely built by TypeScript.

Cocoa is still being developed and haven't been ready for commercial use. Issues / Pull requests are welcome.

Platform

A typical feature of GNU/Linux platform is that there are usually more than one technique/solution to solve the same problem. For example, both PipeWire and PulseAudio are designed to be the audio backend on Linux. Some solutions are too old (but they are usually more stable and compatible, like X11 vs Wayland) and Cocoa does not and will not support them.

Generally, Cocoa always supports the newer technique when we have the choice, and there is a table showing what are or aren't supported:

Feature Support Not support
Display Server Wayland X11, Mir
Graphics Library Vulkan OpenGL
Audio Server PipeWire PulseAudio
Video Decoding Accel. VAAPI (DRM) VDPAU
  • For video decoding acceleration, Vulkan may be supported in the future.

Features

JavaScript Engine

  • ECMAScript 6 support, script files are treated as ES6 modules
  • Synthetic modules: import native language bindings by import keyword directly
  • Asynchronous filesystem API
  • V8 inspector on WebSocket: debug JavaScript with VSCode
  • WebAssembly support: run WASM modules compiled by Emscripten

Rendering (glamor module)

  • Skia-like API
  • Onscreen and offscreen rendering targets
  • Wayland support
  • Raster (CPU) and Vulkan (GPU) rendering backends
  • Asynchronous onscreen rasterization
  • LayerTree-based onscreen rendering
  • PNG, JPEG, Webp encoding and decoding

Other graphical features

  • SVG support (draw SVGs or use SVG as a rendering target)
  • Text layout
  • Lottie animation support
  • Computer vision by OpenCV WASM

Multimedia (utau module)

  • Multimedia decoding based on FFmpeg
  • Hardware-accelerated (VA-API) video decoding
  • Multimedia DAG filtering (some filters are hardware-accelerated)
  • PipeWire
  • Multimedia representation dispatcher
  • Video buffers can be exported as glamor texture

Building

See documentation for more details.

WebAssembly

WebAssembly is an experimentally supported feature. WASM module compiled by Emscripten can be loaded by //typescript/wasm/wasm-loader-polyfill.ts, and WASM modules known to run correctly on Cocoa can be find in //typescript/wasm, like Cairo and OpenCV. Every WASM module in that directory has a tutorial README.md which shows you how to compile it and make it run correctly on Cocoa.

Here is a simple example to load an Emscripten compiled module:

// `wasm-loader-polyfill.ts` is at `//third_party/typescript/wasm/wasm-loader-polyfill.ts`
import { LoadFromFile } from "./wasm-loader-polyfill";

const module = await LoadFromFile('/path/to/module.wasm', '/path/to/module.js');

Third Parties

Cocoa depends on many opensource projects and thanks to them give us a more convenient way to develop Cocoa without suffering.