Lempo Particle FX

Design stunning 2D & 3D particle effects visually in a desktop editor — then play them in GDevelop with the Advanced Particle Emitter extension. The browser preview shares one simulation engine across its renderers; the GDevelop extension keeps a separate runtime.

Editor v0.2.0 Extension v0.2.0 Export v1.2 Windows 10/11 · OpenGL 3.3 MIT License

📥 Download the editor Quick start →

Lempo Particle Editor — live editing with instant viewport feedback — **Lempo Particle Editor** — live editing with instant viewport feedback

What's inside?

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Desktop Editor

Dear PyGui app with live 3D/2D viewport, 12 particle shapes, per-state colors, force fields, deterministic seeds, templates and 100-step undo/redo.

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Trails & Ribbons

Unity-style trail inspector with 79 settings, curve & gradient editors, and 27 ready-made templates across five categories.

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Live Previews

The Dear PyGui viewport uses its drawlist and optional OpenGL raster layer. A separate browser fast preview uses Three.js, PixiJS or Canvas with 500 ms live-sync.

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GDevelop Extension

Advanced Particle Emitter renders your exported JSON in-game — 2D via PixiJS, 3D via Three.js, trails included.

Screenshots

3D viewport — meshes & billboards — **3D viewport** — meshes & billboards

2D viewport — sprites & SVG — **2D viewport** — sprites & SVG

3D browser fast preview (Three.js) — **3D browser fast preview** (Three.js)

2D browser fast preview (PixiJS) — **2D browser fast preview** (PixiJS)

How the pieces fit together

Part	What it is
Lempo Particle Editor	A Dear PyGui desktop app (`LempoParticleEditor.exe`) for designing effects with a live viewport, then exporting them as JSON.
Advanced Particle Emitter	A GDevelop extension (`AdvancedParticleEmitter.json`) that renders those effects in-game: 2D via PixiJS and 3D via Three.js.

The editor, browser preview and extension share export data contracts. The browser preview's Three.js, PixiJS and Canvas adapters use one TypeScript particle engine; GDevelop still has a separate simulation implementation, so some runtime behavior can differ. See Contracts & Export and the viewport migration notes.

Works in any GDevelop project — design the effect in the editor, play it in-game with the Advanced Particle Emitter extension.

Documentation

Page	What's inside
Installation & First Run	Download, requirements, the startup dialog, running from source
Editor Tour	Sidebar, emitter panel, force fields, states, shapes, navigation
Viewports & Previews	Dear PyGui viewport, GL raster layer, browser fast preview
Trails & Ribbons	Modes, inspector, emit types, templates, C++ API
Blend Modes	Normal, Additive, Subtractive, Multiply, Screen, Lighten, Overlay
GDevelop Guide	Import the extension, set resources, run in-game
Contracts & Export	Export format v1.2, particle record layout, migration
Testing	Full test matrix and CI gates
Roadmap & FAQ	What's done, what's planned, common questions