Depth

Until now nothing has stood behind the street but the camera’s Background:

Night Town, from the same download as the castle, is a backdrop in seven pictures: a sky, its clouds, the mountains, a lit copy of the mountains, far buildings, a forest and a town. Each is a layer, and each layer is a plane: a node with a Parallax that moves everything drawn under it by a share of the camera’s motion. The further back a layer is, the less it seems to move, and that is what reads as depth.

+ Add node → Parallax makes a node with a Parallax and a Sprite on it: a plane with one picture. The planes go under the town’s root, from the furthest to the nearest, each on a Sort Layer in front of the one before. The sky is first.

Make the other six the same way, each under town, last, in this order. Each colour here is typed with the picker reading F, as in chapter 1. A field the table does not name stays as it comes. Every picture is in art, named night-town-background- and the layer.

The town’s layer is called townscape because the scene’s root is already town, and two nodes of one scene cannot share a name. lights is the mountains again with their windows lit, laid over them at the same Factor and Offset, so each of its copies is exactly on one of theirs; its Color’s alpha of 0.8 lets a fifth of the plain mountains show through.

Every Factor’s y is 1: up and down, every plane goes with the camera, so a plane’s y is its place in the view and not in the world. The view’s middle rests 24 above his feet, and the view reaches 90 above and below it. The tall pictures are centred on the middle. The forest and the town hang from 64 below it, 40 below the street’s top, so their feet are hidden behind the street. The far buildings hang from 8 above it, so their poles and the church tower stand clear of the forest. The sky is lifted 8 because chapter 7’s view is 240 tall, and the picture 224: without the lift, a strip of Background would show along the top.

A plane carries whatever is drawn under it, particles too. The fog is an emitter with a Parallax on the same node.

The puffs start at half their colour’s strength and fade out, under a plane whose own alpha is 0.6: faint, slow and long-lived. A plane copies only sprites and tilemaps, so the fog is drawn once, wherever the plane carries the emitter. The plane carries it 0.4 of the camera’s way while the view goes the whole street, so the box is 1800 wide, as wide as the stretch of town the view looks through it at.

The nearest plane is a row of roofs, painted from Gothic Horror’s tiles, which the starter holds. Paint them before the plane is added: until it is, the tiles are drawn where you paint them. They go behind the street, so hide the street while you paint.

The tint darkens the roofs to a dull brown, so they sit behind the street and not on it. The run is 77 cells, 1232 units, and with Repeat X off it comes once: with him past about x 1850 it is behind the view for good. Tick Repeat X and it comes round again, copied by the width of the cells you painted.

The game itself, played and recorded at half its window’s size. Play your own with F5.

On the screen a plane moves by one less its Factor, times the camera’s motion. A second into a walk the camera has moved about 104 units (the dead zone and the damping take that long to catch him up, so not his 160): the forest moves about 31 of the screen’s 104, the townscape 52, the rooftops about 73, and the sky none. The clouds drift 6 a second west on top of their share. The fog’s plane carries the emitter, and its puffs with it.

A leap is different: every Factor’s y is 1, so up and down every plane goes with the camera, and stays where it is on the screen. Only the street, which no plane carries, drops away under him.

The castle gets one plane: a brick wall behind its rooms, which repeats up the stair shaft as well as along it. Its picture, old-dark-castle-interior-background.png, is four bays side by side, 240 by 304 each: two with ivy and two without, each pair a bay of lantern-lit brick and a bay with an arched window, whose white lattice would draw the eye from him. The plane draws the first bay, a region of the picture.

Selected, a plane draws its home: the box its art fills where it would be with the camera at the world’s origin, its Offset added. On an axis it repeats along, a ruler runs along the home’s far edge, its bottom for Repeat X and its right for Repeat Y, with a tick where each copy starts:

The home is where the clock starts: a plane is drawn shifted from it by its Factor times where the camera rests. The ticks are every 240 along and every 304 up, the region’s own size, since its Repeat Period is 0. A plane whose art is particles, text or lights alone, as the fog’s is, draws no home: the editor measures only sprites, tiles and shapes. In the town, the camera rests at y -24, so a plane with a Factor y of 1 is drawn in the game 24 higher than its home.

Planes do not stack. A plane under another plane is carried by its own Factor alone: the nearest plane above a node is the one that moves it, and the outer plane’s Factor is not applied inside. Try it, and put it back.

It is a note and not a warning, since nothing is wrong with it: here both Factors are 0.9, and nothing moves differently. A nested plane is for a part of a layer that moves at a pace of its own. Press Undo in the toolbar, and lights is back under town where it was, and the note goes.

At 1280 by 720, chapter 5 draws a frame in 2 draw calls: the street, and him. Chapter 6 takes 11, one for each plane and its picture, and 231 sprites against 122, in the same 2 passes, with 0.85 MB more of pictures in memory. On a desktop, that is nothing.

The project’s Quality settings decide how many planes a frame draws. In File → Project settings…, on its Quality tab, each level has a Layers choice, and the game draws as many planes as the level its Desktop default names allows. Full draws every plane. Reduced keeps the six nearest: here it drops lights, clouds and sky. Minimal keeps the three nearest, townscape, fog and rooftops. The nearest are the planes whose Factor is furthest from 1; of two that tie, as mountains and lights do, the first in the Hierarchy stays.

Nothing new: the rig, every step, and the room holding it. The planes move no camera. Each reads where the camera rests, after the room has held it, and is drawn shifted from its home by its Factor of that. Every plane and everything else in the picture is drawn from the same camera, so a shake, in chapter 8, shakes them together.