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Vector Terrain

Free packv3.0.0-32DVector

Line landscapes for 2D games: one seeded polyline you can sample for a height anywhere, flatten into landing pads and blow craters into, without it ever folding over itself.

This is a Free pack. Every phaser.io account can use it in their games.

Released October 14, 2026 · updated October 20, 2026

Vector Terrain: a screenshot of its demo
A note about these graphics

Expansion packs don't come with graphics. This screenshot is one way of drawing what the pack does, made for its demo: none of the sprites, tiles or backgrounds in it are in the pack.

That's by design. A pack is a game's logic, mechanics and effects, and it works with whatever art you give it. Some packs draw effects, backdrops or 3D scenes of their own, but none carries a game's sprites.

So the look is yours. Make the art on phaser.io, bring your own, or let your agent draw it in code: the same pack can look like anything.

What it does

generateTerrain builds a landscape by midpoint displacement: it repeatedly splits each segment and pushes the new middle up or down by a shrinking amount. One number, the roughness, takes it from rolling hills to a mountain range. Both ends sit at the base height, and with a seed, or the game's own random source, the same landscape comes back every time.

The landscape is single-valued in x by construction, and everything else depends on that. Because no two vertices share an x, heightAtX finds the one segment that spans any x and returns the ground height there with a binary search, cheaply every frame. climbableX tests whether the rise between two positions is within a slope. flattenTerrain lays an exact pad or plateau and returns where it is. craterHeightfield carves a bowl.

A general polyline will not stand that treatment: carve two overlapping craters into an arbitrary outline and the line folds back on itself, after which "the height at x" has no answer. Here a crater only ever pushes vertices down, clamped to a floor, and every function keeps the vertices sorted, so the field stays single-valued however many shells land on it.

Features

  • Midpoint displacement — generateTerrain with a width, a base height, an amplitude, a roughness from 0 to 1, and clamps on how high and low the ground may go.
  • Spacing or passes — ask for a widest vertex gap with spacing, or a number of iterations, up to 16 passes.
  • Seeded — a seed or an rng; through game.vecTerrain it draws from the game's random source by default, so terrain replays with the game's seed.
  • Height anywhere — heightAtX by binary search, Infinity off either end.
  • Landing pads — flattenTerrain makes the ground flat between two x positions, at a height you choose or the middle's, and returns the pad.
  • Slope tests — climbableX checks a rise against a maximum slope; downhill always passes.
  • Craters — craterHeightfield lowers the ground inside a circle to a bowl, never below a floor, optionally refining the ground under it first.
  • Detail on demand — refineTerrain adds vertices in a span without changing its shape, so a crater can bite into ground generated coarsely.

Good for

  • Lander games — a jagged landscape with flat pads, in the style of Lunar Lander.
  • Artillery games — ground that craters under every shell and stays a clean line.
  • Side-scrolling shooters — the ground and, with a second field, the ceiling of a cave, in the style of Scramble.
  • Moon-buggy and driving games — a surface to sample under the wheels, with slope checks for climbing, in the style of Moon Patrol.

Make it yours

The options shape the land: width and baseY, the first displacement amplitude, the roughness that decides how much survives each pass, iterations or a spacing, minY and maxY clamps, and a seed or an rng. A cave is two landscapes from two calls, a ceiling with a small baseY and a floor with a large one; a vertical shaft is a landscape generated across the height and mapped with x and y swapped, then sampled with heightAtX(shaft, y).

Two very different games from the same calls: a lunar landing on a 2,400-unit landscape with a roughness of 0.55 and two flattened pads at different heights; and an artillery duel on gentle rolling hills where every shell calls craterHeightfield with a refinement step, so the ground under the tanks wears away shot by shot.

A quick look

A lunar landscape with two pads, a landing check, and a crater handed back to the drawn line:

const T = game.vecTerrain;
const ground = T.generateTerrain({ width: 2400, baseY: 520, amplitude: 180, roughness: 0.55, spacing: 12, minY: 260, maxY: 700 });
const pads = [T.flattenTerrain(ground, 400, 460), T.flattenTerrain(ground, 1500, 1540, 610)];
const line = game.vector.shape(ground, { closed: false, color: '#c8d0ff' });
if (craft.y + 10 >= T.heightAtX(ground, craft.x)) { /* landed on a pad, or crashed on the rocks */ }
T.craterHeightfield(ground, shell.x, shell.y, 24, 700, { step: 4 });
line.setPoints(ground, false);

Works with

  • vector-2d — draws the line, and takes the changed points after a crater.
  • vector-hit — collision against the line, through its wall segments.
  • physics-box2d — makes the line solid ground for bodies, as a chain.
  • thrust-craft — caves of several chains with graded contact, built on these heights.
  • lander-missions — landing-site rules and scoring.
  • excavation, procgen and terrain-3d — terrain dug cell by cell, seeded noise for other shapes, and the 3D counterpart.

Good to know

  • One line, with no overhangs and no caves in a single field: a tunnel needs two fields or a different representation.
  • Without a refinement step, a crater narrower than the vertex spacing only moves the vertices inside it, so it carves a notch or nothing.
  • A crater's floor bounds how deep the crater digs, not the terrain: ground already below it is left alone.
  • climbableX is a two-point slope test, not a walk, so a vehicle that should stop partway up a hill has to step it itself.
  • The functions change the array in place, so anything built from it, a drawn shape or a physics chain, must be given the new points.

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