Block it out

Worlds and Levels builds one level, Hollowmere, seen from the side: a vale ten screens wide, from a hut at its west end to a chapel at its east, and a crypt under the chapel. A pilgrim walks it. Nothing in it is made yet. This chapter blocks the whole vale out in grey, and each chapter after it replaces grey stand-ins with the real thing, so the vale can be walked end to end at every step.

The starter is worlds-and-levels.zip. It holds the project, its two scenes, the vale and the crypt, the chapel door’s script, the pilgrim and every picture drawn for the tutorial. The five pictures and the font that chapters 2, 6, 7, 10 and 14 ask you to download are not in it.

One unit is one art pixel, and y grows downward: the vale’s walking line is y 0, and a place above it has a negative y. The vale is 3200 units wide, ten screens of 320, and the pilgrim walks it at 160 a second. Its nodes:

He walks with A and D or the arrow keys, and leaps with Space, W or the up arrow. The crypt, scenes/crypt.ron, holds the same: him at 64, 0, where chapter 2’s stair will rise, his camera, and nothing else.

A second in, his feet are past y 400, straight below where he stood, and he is still falling. The camera stands at his framed point from the first frame, so it has nothing to catch up on; it follows him down into nothing. The first thing to make is something to stand on.

A level designer blocks a level out before any art exists: a box for every floor, wall and thing, in grey, so the level can be walked, its distances felt and its pieces moved while moving them still costs nothing. + Add node has two presets for it. A Shape draws an untextured rectangle, circle or capsule and holds nothing up. A Block is a Shape and a Collider of one size: what you see is what he stands on.

Reach for a Block wherever he walks, and a Shape wherever he does not. Later chapters replace the grey with the tool each thing wants: tiles for the buildings, painted from a grid of art (chapters 2 to 4); a Sprite Shape for the hills, a curve with edges (chapter 5); a Polygon for the mere, a flat outline (chapter 6); a Mesh for the sky, a shape you colour and map yourself (chapter 7); and a MultiMesh for the meadow, many copies of one shape (chapter 8).

Front and back are the Sort Layer first. Every node that draws stores one, a number, and a higher number draws in front; the project names the numbers. The starter names one, Default. Hollowmere uses eight, named once, back to front, and never reordered.

The names are written to sorting-layers.ron; the project file is left as it was. A node stores the number, not the name. The starter’s pilgrim was already at 6, so he is on Figures from now on without being touched. And moving a node up or down the Hierarchy never brings it in front of a node on a later layer.

The ground first. He walks the vale on one slab of grey, 320 deep, with the ravine cut out of it near the east end and bridged level, so D alone takes him from the hut to the chapel door. That is six Blocks, every one hung from the middle of its top, so its node is on the walking line.

A Block’s Shape and Collider are one box. The Collider’s size is the Shape’s, and its offset is the Shape’s middle: 0, 8 on the bridge, half its 16 below a node hung from its top. While they match, the Viewport draws them as one outline with one set of handles, and a drag writes both. The bridge shows two corners, its bottom two: the anchor on its top edge pins the top two, so they are no handles.

Drag the anchor with the Select tool. A fresh editor starts on the Move tool, and under it the ring sits under the gizmo’s middle square, which takes the drag; the corners work under every tool. Make the other five Blocks the same way, each a child of vale:

All six have Anchor 0.5, 0, Sort Layer Ground, the grey, and an Outline of 1 in 0.25, 0.25, 0.28. Every corner is on the 16 grid, and every top is the walking line: the ground runs from x -64 to 3200 with the ravine’s 160 cut out of it, bridged level, and the chapel’s grey floor lies on the east ground’s top. Nothing he walks on rises above y 0.

Everything he walks past and does not stand on is a Shape alone: the sky, the sun, the hut, the cliff, the mere, the meadow, the carts, the stalls, the banner and the four signposts. A Shape draws and holds nothing up, so its values are typed: there is no Collider to keep in step.

They go under the six Blocks, each a child of vale, in the order of the table: the sky and the sun first, then the hut. Each is named …-block, so the made thing that takes its place in a later chapter can take the plain name, and each is grey with an Outline of 1 in the darker grey, but the sun. All are Rectangles but the sun, a Circle, and the carts, Capsules. A signpost’s post goes under its board, as the board’s child.

The hut, the third, shows a Shape’s rows: Size 128, 96, and Anchor 0.5, 1, so it stands on its foot, the middle of its bottom edge, on the walking line; on Back.

The grey sky ends at the walking line, so the ravine shows the camera’s Background under the bridge. The sun is the one stand-in in colour, its ring 3 wide inside its edge:

The sun is on Far, not on Sky where it belongs by sense, because of how it is drawn. A round Shape with an outline is drawn as a mesh, and on one Sort Layer a mesh is drawn before a box it ties with: on Sky the grey sky’s box, drawn after it, would cover it. Far is in front of Sky, so the sun is drawn after the sky, whatever the Hierarchy says. Front and back are always the Sort Layer first.

Every kind of thing this tutorial draws answers the same three questions differently, and each chapter asks them of its own. Of the grey stand-ins:

• What collides: a Block, through its Collider. A Shape alone collides with nothing.
• What draws: both, their fill and their outline.
• What sorts: the Sort Layer first; on one layer, a round outlined Shape, a mesh, before a box. Never the Hierarchy.

Put him 60 above the middle of the mere and he falls straight through it and lands on the ground beneath, at y 0. The mere is drawn and holds nothing up, as the real mere will: he walks past it, not on it.

Held all the way, D takes him to the chapel door within 25 seconds. His feet never sink under the walking line, over the bridge and onto the chapel’s floor too, and no seam between two Blocks stops him or turns him back: at the door, the game changes to the crypt, where he falls, for nothing is built there yet. Chapter 2 gives it a floor.