Libgdx Particles

libGDX Particle Effects

Quick reference for libGDX particle systems. Covers 2D ParticleEffect/ParticleEmitter/ParticleEffectPool, AssetManager loading, blend function management, and the 3D particle system (g3d.particles).

2D ParticleEffect

com.badlogic.gdx.graphics.g2d.ParticleEffect implements Disposable.

Loading

ParticleEffect effect = new ParticleEffect();

// From loose image files (images directory):
effect.load(Gdx.files.internal("explosion.p"), Gdx.files.internal("particles"));
//          ^ effect file                       ^ directory containing particle images

// From TextureAtlas:
effect.load(Gdx.files.internal("explosion.p"), myAtlas);

// From TextureAtlas with prefix:
effect.load(Gdx.files.internal("explosion.p"), myAtlas, "fx_");

The second parameter to load(FileHandle, FileHandle) is the images directory, NOT the effect file's parent. A common mistake is passing "" — use Gdx.files.internal("") for project root.

File format is .p (plain text), created by the Particle Editor tool.

Core Lifecycle

effect.start();                      // starts all emitters
effect.setPosition(x, y);           // set position on all emitters

// In render():
effect.update(Gdx.graphics.getDeltaTime());
effect.draw(batch);                  // param type is Batch (interface), not SpriteBatch

// Or combined:
effect.draw(batch, delta);           // calls update(delta) then draw(batch)

if (effect.isComplete()) { ... }     // true when ALL emitters are complete

effect.reset();                      // kills particles, resets scaling, restarts
effect.dispose();                    // only frees textures if loaded from directory (not atlas)

Key Methods

Scaling

effect.scaleEffect(2f);             // scale size AND motion by 2x
effect.scaleEffect(2f, 1f);         // scale size by 2x, motion by 1x
effect.scaleEffect(2f, 3f, 1f);    // xSize=2x, ySize=3x, motion=1x

WARNING: scaleEffect() is MULTIPLICATIVE. Each call multiplies onto the existing tracked scale. Calling scaleEffect(2f) twice results in 4x scale, not 2x. Call it once after loading.

reset(true) (the default) reverts scale to 1.0 by applying the inverse. reset(false) preserves the current scale — this is what ParticleEffectPool.free() uses.

Disposal

dispose() only frees textures when ownsTexture is true — i.e., when loaded via load(FileHandle, FileHandle) (directory). When loaded from a TextureAtlas, the atlas owns the textures and dispose() is a no-op. Dispose the atlas separately.

ParticleEmitter

com.badlogic.gdx.graphics.g2d.ParticleEmitter — each effect contains one or more emitters.

Key Methods

ParticleEmitter emitter = effect.findEmitter("sparks");

emitter.setContinuous(true);         // emitter loops
emitter.isContinuous();

emitter.allowCompletion();           // gracefully finish: stops spawning, existing particles live out
emitter.isComplete();                // true when done spawning AND all particles dead
emitter.getPercentComplete();        // 0.0–1.0

emitter.setPosition(x, y);
emitter.getX();  emitter.getY();

emitter.setAdditive(true);           // additive blending (default: true)
emitter.setPremultipliedAlpha(false); // premultiplied alpha (default: false)
emitter.setCleansUpBlendFunction(b); // restore blend state after draw (default: true)

emitter.getMaxParticleCount();
emitter.setMaxParticleCount(500);
emitter.getActiveCount();

Emitter Value Properties

All return value objects (not primitives). Modify via their setters.

The duration and durationTimer fields are public floats (milliseconds) and can be accessed directly.

There is NO setColor() on ParticleEmitter. Color is set via getTint() which returns a GradientColorValue.

SpriteMode Enum

ParticleEmitter.SpriteMode: single, random, animated — controls multi-sprite behavior per emitter.

ParticleEffectPool

com.badlogic.gdx.graphics.g2d.ParticleEffectPool extends Pool<PooledEffect>. Use to avoid GC from repeatedly creating/disposing effects.

// Create pool from a template effect (loaded once):
ParticleEffect template = new ParticleEffect();
template.load(Gdx.files.internal("explosion.p"), Gdx.files.internal("particles"));

ParticleEffectPool pool = new ParticleEffectPool(template, 4, 16);
//                                               effect  initial  max

// Obtain and use:
ParticleEffectPool.PooledEffect effect = pool.obtain();
effect.setPosition(x, y);

// In render():
effect.update(delta);
effect.draw(batch);

// When done (isComplete or manually):
effect.free();     // returns to pool — calls reset(false) internally (preserves scale matching)

// DO NOT call effect.dispose() — that would break the pool.

PooledEffect extends ParticleEffect. The free() method is a convenience that calls pool.free(this). The pool's free() resets the effect without resetting scaling, then re-matches scale to the template.

Standard Pool Pattern

Array<ParticleEffectPool.PooledEffect> activeEffects = new Array<>();

// Spawn:
ParticleEffectPool.PooledEffect effect = pool.obtain();
effect.setPosition(x, y);
activeEffects.add(effect);

// Update/draw:
for (int i = activeEffects.size - 1; i >= 0; i--) {
    ParticleEffectPool.PooledEffect effect = activeEffects.get(i);
    effect.draw(batch, delta);
    if (effect.isComplete()) {
        effect.free();
        activeEffects.removeIndex(i);
    }
}

AssetManager Loading

com.badlogic.gdx.assets.loaders.ParticleEffectLoader — synchronous loader for 2D effects.

// Default: images from effect file's parent directory
manager.load("particles/explosion.p", ParticleEffect.class);

// With TextureAtlas:
ParticleEffectLoader.ParticleEffectParameter param =
    new ParticleEffectLoader.ParticleEffectParameter();
param.atlasFile = "particles/particles.atlas";  // String, not FileHandle
// param.atlasPrefix = "fx_";                   // optional prefix for region names
manager.load("particles/explosion.p", ParticleEffect.class, param);

// With explicit images directory:
ParticleEffectLoader.ParticleEffectParameter param =
    new ParticleEffectLoader.ParticleEffectParameter();
param.imagesDir = Gdx.files.internal("particles/images");  // FileHandle, not String
manager.load("particles/explosion.p", ParticleEffect.class, param);

ParticleEffectParameter fields:

Default (no param): loads images from the .p file's parent directory.

Blend Function Management

Particle emitters default to additive blending (additive=true). After drawing, the emitter restores the batch's blend function to standard alpha blending — controlled by cleansUpBlendFunction (default: true).

// Disable cleanup for performance when drawing many additive effects in sequence:
effect.setEmittersCleanUpBlendFunction(false);
// ... draw multiple effects ...
// Manually restore blend function:
batch.setBlendFunction(GL20.GL_SRC_ALPHA, GL20.GL_ONE_MINUS_SRC_ALPHA);

Setting cleansUpBlendFunction=false avoids redundant batch flushes between effects that share the same blend mode. You MUST restore the blend function manually before drawing non-particle sprites.

Particle Editor

Standalone tool for creating/editing .p files.

• Legacy: com.badlogic.gdx.tools.particleeditor.ParticleEditor in gdx-tools (Swing + LWJGL2, issues on macOS/Apple Silicon).
• Recommended: gdx-particle-editor — pure Scene2D UI, works on all platforms. Exports same .p format.

3D Particle System (Brief)

Package: com.badlogic.gdx.graphics.g3d.particles — entirely separate from 2D particles. Different classes, different APIs, different file format.

DO NOT confuse com.badlogic.gdx.graphics.g2d.ParticleEffect (2D) with com.badlogic.gdx.graphics.g3d.particles.ParticleEffect (3D). They share the same simple class name but are unrelated.

Architecture

3D Setup Pattern

// ParticleSystem manages batches and effects
ParticleSystem particleSystem = new ParticleSystem();

// Create a batch (camera-facing quads):
BillboardParticleBatch billboardBatch = new BillboardParticleBatch();
billboardBatch.setCamera(camera);
particleSystem.add(billboardBatch);

// Other batch types:
// PointSpriteParticleBatch   — GPU point sprites (efficient, less flexible)
// ModelInstanceParticleBatch — 3D model instances (expensive, most versatile)

// Load via AssetManager:
Array<ParticleBatch<?>> batches = new Array<>();
batches.add(billboardBatch);
ParticleEffectLoader.ParticleEffectLoadParameter loadParam =
    new ParticleEffectLoader.ParticleEffectLoadParameter(batches);
manager.load("effect.pfx", com.badlogic.gdx.graphics.g3d.particles.ParticleEffect.class, loadParam);

// Render loop:
particleSystem.update();
particleSystem.begin();
particleSystem.draw();
particleSystem.end();
modelBatch.render(particleSystem);  // ParticleSystem implements RenderableProvider

The 3D ParticleEffectLoader is at com.badlogic.gdx.graphics.g3d.particles.ParticleEffectLoader — a SEPARATE class from the 2D loader. You MUST pass batches via ParticleEffectLoadParameter.

Note: The 3D particle system is complex and less commonly used. See the libGDX wiki on 3D particle effects for detailed documentation.

Common Mistakes

1. Calling scaleEffect() every frame — It multiplies onto existing scale. Calling scaleEffect(2f) twice = 4x scale. Call it once after loading, or track and undo with reset(true).
2. Forgetting update(delta) — Particles freeze in place. Must call every frame (or use draw(batch, delta) which combines both).
3. Calling dispose() on pooled effects — Use effect.free() to return to pool. dispose() destroys the textures and breaks the pool.
4. Loading in render() — new ParticleEffect() + load() is expensive. Load once in create(), then reuse or pool.
5. Wrong second argument to load() — The second parameter is the images directory (FileHandle), not the effect file path. Pass Gdx.files.internal("particles") for images in assets/particles/.
6. Calling setPosition() only once — Position is not inherited from a parent. If the effect follows a moving entity, call setPosition() every frame.
7. Disposing atlas-loaded effects — dispose() is a no-op when loaded from TextureAtlas (atlas owns the textures). Dispose the atlas instead.
8. Inventing effect.setColor() — Does not exist. Color is per-emitter via emitter.getTint() which returns a GradientColorValue.
9. Not calling start() after loading — A freshly loaded effect needs start() before particles emit. (Pool's obtain() calls start() automatically.)
10. Confusing 2D and 3D ParticleEffect — Same simple class name, different packages (g2d vs g3d.particles), completely different APIs. Wrong import = compile errors or wrong behavior.
11. Using allowCompletion() on non-continuous emitters — Only meaningful for continuous emitters. On non-continuous emitters it just sets durationTimer = duration, which may cause them to stop prematurely if called early.
12. Rendering particles outside SpriteBatch begin/end — effect.draw(batch) must be called between batch.begin() and batch.end(). The effect uses the batch's current projection matrix and blend state.

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