Skip to content
Rengy
Menu

Tutorials

Particle Effects

about 6 hours 16 chapters

Fill a night town with particles, one control at a time: chimney smoke, a fountain, rain and fog, forge fire and sparks, fireflies, a coughing chimney, forces, rain that lands and splashes, fireworks, scripts, lamps and a glow, sparks in their own colours and a lantern-bat’s ribbon, and what each costs on a phone, then a gallery of six effects.

The finished town at night, playing: rain streaking down across the whole picture, smoke curling from two chimneys, a dark puff of soot now and then above the roofs, fire and sparks in the forge’s mouth at the left, fog along the street, the fountain’s jet, a warm light round each of the two street lamps, yellow fireflies at the right and now and then a ring of blue sparks at the well. A bat flits above the roofs trailing a warm ribbon, a shooting star crosses the upper sky from the left, and three firework shells burst high at the right into rings of coloured sparks
On this page

The town

Particle Effects fills one scene, Night Town: a town square at night in pixel art, with houses, a forge, a fountain, a well and two street lamps under a sky of clouds and mountains. The camera is fixed on it, so it is a showroom. You press Play and watch it; nothing is steered. You start from a starter with the town built and nothing moving in it, and add effects to it, a control at a time. A last chapter then finishes six small scenes of their own, each a recipe to take into your own game.

The tutorial is for learning every particle control to the end. Each one is defined with what it does, its unit and the range that looks right in the town. A control whose effect is not obvious is shown at the values that matter, side by side, and small effects are shown close up. A note says why wherever a result surprises you, and what it costs wherever it costs, on a phone most of all. Each effect ends with its values in a table, so you can build it again in your own game.

Each part ends on a town that looks finished at its level:

The town at the end of Part 1: grey smoke rising in a straight column from the first chimney, the fountain’s jet as a fine spray of pale blue dots rising over its basin, a pale fog lying along the street, a ring of blue-white sparks at the well, and the rain as a scatter of tiny pale dots across the sky
Basic, after chapter 4.
The town at the end of Part 2: flames flickering in the forge’s mouth with orange sparks flying out and a column of grey smoke rising above it, rain falling in streaks, smoke curling from two chimneys, a few yellow fireflies drifting over the right-hand houses, a pale fog along the street, and a ring of blue sparks at the well
Simple, after chapter 9.
The town at the end of Part 3: the same rain, smoke, fog and fountain, now with the street dark but for a warm glow round the two street lamps, the forge’s fire and the yellow fireflies glowing, a soft glow round the brightest points, three rings of coloured sparks bursting at the upper right, a shooting star’s dotted tail at the top left, and a bat above the roofs with its warm ribbon
Pro, the town lit and glowing, after chapter 14. Chapter 15 then trims it for a phone, and chapter 16 leaves the town for six scenes of their own.

What you need

  • Rengy, installed, on Windows or Linux. Getting started installs it and shows you round the editor.
  • The starter, particle-effects.zip: the town built with nothing moving, and every picture it uses. Unzip it somewhere outside your other projects; in the editor’s launcher, choose Open project… and pick the particle-effects folder.
  • Nothing else. Parts 1 and 2 are all clicks. Part 3 has six short Rengy Script files and one small shader, which the editor runs as they are, with nothing to install.

The town’s art is from the Gothicvania collection by ansimuz (Luis Zuno), in the public domain (CC0). The starter holds twelve pictures from the collection, the town’s layers and the gallery’s, and sixteen small ones cut out of them or drawn for the effects: a soft dot, sparks, smoke, a raindrop, flames, a snowflake, a leaf and the like.

Three parts

You can stop after any of them: each leaves you a town that works. The chapters below are listed by part.

  • Basic, chapters 1 to 4: the first puffs. Chimney smoke, a fountain that arcs, rain from the sky, fog along the street and a ring of light at the well.
  • Simple, chapters 5 to 9: making them look real. Forge fire that flickers through its frames, sparks that streak and trail, rain streaks, fireflies and curling smoke, a puff of soot, and a town that opens already smoking.
  • Pro, chapters 10 to 16: forces, chains and cost, then a gallery. Fireflies drawn to a lamp, rain that lands and splashes, fireworks, scripts that fire bursts and hear particles, lamps and a glow, sparks in their own colours, a lantern-bat’s ribbon, the town budgeted for a phone and exported, and six effects to take into your own game.

How long it takes

The sixteen chapters take about six hours at the keyboard, in sittings of fifteen to forty-five minutes. Every chapter ends at a place you can stop, with a Check it works box that says what you should see.

The chapters

Part 1 · Basic

The first puffs: chimney smoke, a fountain that arcs, rain from the sky, fog along the street and a ring of light at the well.

  1. 1 One emitter Put a chimney’s smoke on the town with one emitter: how many it makes, how long they live, how fast and which way they go, and how many can be alive at once. 20 min
  2. 2 Colour, size, fading Turn the chimney’s white dots into smoke: a grey that fades, a size that grows, a soft picture to draw, and the five ways a particle can meet what is behind it. 20 min
  3. 3 Gravity and drag Make the fountain’s water rise and fall back into its basin, and slow the chimney’s smoke into a plume: what Gravity pulls with, and what Drag takes away. 15 min
  4. 4 Where particles are born Rain from a line across the sky, fog from a box along the street, a ring of light on the well’s rim, and the fountain’s jet from a cone. 25 min

Part 2 · Simple

Making them look real: forge fire that flickers through its frames, sparks that streak and trail, rain streaks, fireflies and curling smoke, a puff of soot, and a town that opens already smoking.

  1. 5 Curves and gradients Forge fire that runs white, yellow, orange and smoke grey over its life, and sparks that shrink and redden as they slow. 25 min
  2. 6 Flipbooks and spin The fire redrawn as flames that flicker through eight frames, sparks that point along their flight, and billowing smoke that turns as it rises. 25 min
  3. 7 Streaks Rain that falls as streaks, longer the faster it goes, and sparks that leave a short trail of themselves behind. 15 min
  4. 8 Wandering Fireflies that drift on invisible currents, and two chimneys whose smoke curls instead of climbing straight. 20 min
  5. 9 Bursts and prewarm A chimney that coughs one puff of soot, a town that opens with its smoke already rising, and pools sized to what they hold. 20 min

Part 3 · Pro

Forces, chains and cost, then a gallery: fireflies drawn to a lamp, rain that lands and splashes, fireworks, scripts that fire bursts and hear particles, lamps and a glow, sparks in their own colours, a lantern-bat’s ribbon, the town budgeted for a phone and exported, and six effects to take into your own game.

  1. 10 Forces Attractors: fireflies drawn to a street lamp, a swirl of light at the well, and a push that fans the fountain out. 20 min
  2. 11 Collision Rain that lands on the roofs and the street and bounces a little, and sparks that skid across the cobbles. 15 min
  3. 12 Particles that make particles Every raindrop splashes where it lands, and a firework shell bursts into a shower that keeps its speed. 25 min
  4. 13 Particles and scripts Your first scripts: fireworks fired on a timer, a wishing well that hears the fireflies, a chimney that coughs, and a shooting star thrown across the sky. 30 min
  5. 14 Light, glow and your own look Street lamps that light the smoke and the rain, embers that glow, moths seen only in the light, a glow over the town, sparks each in a colour of its own, and a lantern-bat’s ribbon. 30 min
  6. 15 Particles on a phone What particles cost on a phone, why big soft ones cost more than many small ones, and the town budgeted, previewed at the Android tier and exported. 25 min
  7. 16 A gallery of effects Six small scenes finished with what you have learned — snow, an explosion, waterfall mist, falling leaves, a portal and dust in a shaft of light — each a recipe to take into your own game. 45 min

Start with chapter 1, One emitter →