Particles

DownDraft includes a GPU compute particle system with configurable emitters.

Basic Usage

import { ParticleSystem, createFireEmitter } from "@downdraft/engine";

const particles = new ParticleSystem({
  maxParticlesPerEmitter: 5000,
  useGPUCompute: true,
  surfaceFormat: "rgba16float",
});
particles.prepare(device);

const emitterId = particles.registerEmitter(
  createFireEmitter({ position: [0, 1, 0] })
);

// In update loop:
particles.update(dt);

// In render pass:
particles.render(ctx, viewProj, cameraPos);

Smoke Emitter

import { ParticleSystem, createSmokeEmitter } from "@downdraft/engine";

const particles = new ParticleSystem({
  maxParticlesPerEmitter: 10000,
  useGPUCompute: true,
  surfaceFormat: "rgba16float",
});
particles.prepare(device);

const smokeId = particles.registerEmitter(
  createSmokeEmitter({ position: [0, 2, 0] })
);

// Update each frame
particles.update(dt);
particles.render(renderCtx, camera.viewProj, camera.position);

GPU Compute

When useGPUCompute is true, particle simulation (position integration, lifetime, spawning) runs on the GPU via compute shaders. This enables tens of thousands of particles with minimal CPU overhead.

Built-in Emitters

Emitter	Description
createFireEmitter	Fire effect with upward velocity, color fade, and size shrink
createSmokeEmitter	Smoke effect with slow upward drift and expansion

Custom emitters can be created by implementing the emitter interface.