Styles

A style changes how a cloud layer looks, in steps that each change the colour or shape of the faces. It has up to three looks:

• a server look that every player sees,
• a shader look for players who loaded the cloud fog pack,
• a post look, a screen effect on top, which players on Minecraft 26.3 and newer can get.

Styles live in the cloud-styles folder, and a layer file picks one with style.

shader:
  steps:
    puffs:
      kind: puffs
      scale: 40
    shading:
      kind: light
      amount: "1 + 0.3 * puff-up - 0.25 * smoothstep(0.25, 0.6, puff-gap)"
    tones:
      kind: bands
      count: 4
    line:
      kind: ink
      width: 1.5
  post:
    round: 8
    ink: 2

Puff shading in 4 flat tones with an ink outline, plus a post look on 26.3.

Shipped styles

No shipped layer uses a style until you give it one.

wisp suits see-through layers such as cirrus, the others solid layers such as cumulus. The variables, with their shipped value:

• warmth (0.35): warmth of the sun side at sunrise and sunset, 0 to 1.
• edge-softness (10): width of the outline fade, in blocks.
• low-y and high-y (224 and 480): block Y of the darkest and lightest sides (soft), or where the side shadow is deepest and where it is gone (toon). Set them to your cloud bases and tops: style: {use: soft, low-y: 256, high-y: 512}.
• depth-shading (0.18): how much darker the base is than the top, 0 to 1.
• detail, flatten, puff-light, valleys (0.25, 0.7, 0.7, 1): puff shading strength, how far all faces are pulled to one brightness, the share of light from the puffs, and the depth of the gaps between them.
• contrast (0.22): darkening of sides and bottoms away from the sun and at night, 0 to 1.
• dusk-glow (0.5): how pink the layer turns at sunrise and sunset, 0 to 1.

Style files

Each file in cloud-styles is one style, named after the file (a-z, 0-9, _ and - only). The plugin copies the shipped styles when they are missing and never overwrites yours.

Steps

server.steps and shader.steps hold named steps, run in file order, each with a kind and that kind's settings.

• Step names (lower-case words joined by -) are only labels.
• Settings are numbers or quoted formulas, except kind, blend, lit and the colours.

Server steps

• Each amount is rounded to colour-steps steps (1 to 64, default 16).
• live (0 to 1) passes a value per face, such as weather, to the shader input live, in 16 steps.
• A look that follows sun-height or golden-hour resends the whole layer to every player at each colour step during sunrise and sunset, so keep colour-steps low and such looks off large layers.

Shader steps

• Settings stay inside their range, except a formula amount of a color step.
• A puffs step, and any step that reads world-x, world-y, world-z, puff-up or puff-gap, runs on 26.2 and newer only. Older clients skip it.
• Players who get the post look skip feather, so their outline needs the post soften or stays hard (the console warns). They skip ink too when post.ink is set.
• feather treats an edge as outline only with open sky in front of it and up to three voxels behind it. ink, and formulas reading edge, edge-px or outline-px, use every outer edge. With both, the feather rule wins and the console warns.

Variables and formulas

• Variable names are lower-case words joined by -, but not use or the name of an input or function. A variable may not refer to itself through other variables.
• A formula can use numbers, + - * /, parentheses, variables, inputs, and the functions min, max, abs, clamp, mix, smoothstep, step, sin, cos, pow, sqrt, floor and fract.
• Write a - b with spaces, since a - between letters joins a name.
• Dividing by 0 and sqrt of a negative give 0, and an input without a value reads 0.
• A value belongs to the side whose inputs it reads: server steps cannot read shader inputs, and shader steps cannot read server inputs. Pass weather to the shader with live.

These functions work in shader steps only:

Inputs

Server inputs:

Shader inputs:

top, bottom and side work in both server and shader steps: 1 on a face of that kind, 0 otherwise.

• An outline edge is a face edge with nothing of the cloud beyond it, by the rules under Shader steps. edge counts less on faces seen almost edge-on.
• edge, face-width and face-height are estimates, so use them for gradual changes, not hard cut-offs.

Post look

Players on Minecraft 26.3 and newer get the post look while clouds.shader-pack.post-effects is on, see Shader Pack. Any style can set it under shader.post, in plain numbers. Pixel sizes are for a 1080 pixel tall window and scale with it.

• A style gets a post look when round, soften, puff, crevice or ink is above 0.
• With puff, ink still follows the block outline over the rounded-off corners, and the console warns.
• ink and crevice fade out by 1024 blocks, or follow clouds.shader-pack.fog-start and fog-end when those are set.
• See-through layers never get a post look, and anything see-through drawn over a cloud (ground fog, rain, another layer) hides that part from it.

Examples

Storms and dusk for every player, no pack needed:

server:
  colour-steps: 8
  steps:
    storm:
      kind: color
      blend: multiply
      color: "6A7180"
      amount: "storm"
    dusk:
      kind: color
      color: "FF9AB8"
      amount: "0.6 * golden-hour * max(0, facing-sun)"

Slate grey in storms, pink on the sun side at dusk.

Glowing cloud bottoms over a lava sea:

shader:
  steps:
    glow:
      kind: color
      color: "FF7A3A"
      amount: "0.6 * bottom * (1 - height-ramp(80, 200))"

Before 26.2 every bottom glows at half strength, since height-ramp reads 0.5 there.

Eaten edges, after a puffs step:

    erode:
      kind: opacity
      amount: "1 - (1 - step(20, edge)) * step(mix(1, 0.2, 0.5 * (1 - edge / 20)), puff-gap)"

Cuts the gaps between puffs out of the cloud within 20 blocks of its outline, more toward the edge (26.2+).

Using a style

Only the layer file picks a style, never a season, world or profile.

style:
  use: billowy
  depth-shading: 0.25

• use names a file in cloud-styles. Without the file, the layer keeps its plain look and the console says so.
• Other keys must be variables of the style, as numbers or formulas. A value that would make a server step read a shader input, or the reverse, is ignored with a console message.

A season, world or profile can change a layer's style variables under cloud-layers.<layer>.style, with numbers, operators like "*1.4", keyframes and formulas:

atmosphere:
  cloud-layers:
    cumulus:
      style:
        warmth:
          START: 0.2
          END: 0.6

In a season file.

Only the server look follows these changes. A variable only the shader reads keeps its file value, with a warning.

Who sees the shader look

A player sees the shader look when all three hold:

1. The cloud fog pack is on. It holds shader looks for at most 16 layers whose style has shader steps or a post look.
2. Your players get that version of the pack (the plugin checks Nexo's pack, or you set clouds.shader-pack.served).
3. The player's client loaded the pack.

Everyone else sees the server look. A changed shader look needs a restart, and players need the new pack.

• Players with a shader pack loaded in Iris or a similar mod see the server look. Sodium and ImmediatelyFast work with both looks.
• With MythicHUD's pack also served, clients on 1.21.6 to 1.21.8 and 26.1 see only the server look.

Checking a style

• /ms atmosphere profile prints style <name>; shader steps: <steps>; post: <settings> for each styled layer, then each variable with its value and source.
• /ms atmosphere stats shows shader looks on and post effect on on the Renderer: line for a player who gets them.
• /ms atmosphere info shows on the Fog pack line how many shader looks the pack holds and whether players get them.
• Console warnings start with the file and the step, for example cloud-styles/soft.yml shader.steps.outline: 'blokcs' is not a setting of a feather step (its settings are blocks, kind, pixels, top), ignoring.