Specification

This specification defines a format outlining a set of rules for custom sky rendering. These rules can be organized into 11 groups. Please refer to the side panel for the table of contents.

To start writing your configuration for your skybox, create a text file, and save it as a .json. The format starts with a { and ends with a }. In between you can start adding your parameters from these 11 groups, called objects. Each object is separated by a , and can be be arranged in any order.

Throughout the document, you will find examples. Additionally, at the bottom of the page, you'll find examples of various skybox types, demonstrating the structure of a complete file. Template files are also provided to assist you in starting your own pack quickly.

1. Schema version

The current version is 2, but this may change in the future. The mod isn't yet stable since we are in the 0.x phase. This object is required.

"schemaVersion": 2

2. Type

There are three main types of skyboxes: monocolor skyboxes, textured skyboxes, and vanilla skyboxes. One of the 3 types is required.

2.1 Monocolor skyboxes

Name	Description
monocolor	Shows a single plain color for the full skybox.

"type": "monocolor"

2.2 Textured skyboxes

Name	Description
square-textured	uses 6 separate 1:1 aspect ratio texture files for the 6 sides of the skybox
animated-square-textured	uses multiple sets of 6 separate 1:1 aspect ratio texture files for an animated skybox
single-sprite-square-textured	uses a single 3:2 aspect ratio texture file for the skybox
single-sprite-animated-square-textured	uses multiple 3:2 aspect ratio texture files for an animated skybox
multi-texture	uses a grid of textures- arranged in a single texture atlas- for an animation

"type": "single-sprite-square-textured"

Example for (animated-)square-textured skybox

Example for single-sprite-(animated-)square-textured skybox

Here's an example of an animation texture used for the multi-texture skybox type. Frames should be ordered from top to bottom, then left to right as seen below. Each frame can be of any size and aspect ratio. However, the combined size of the texture should not exceed 8192x8192 pixels. Only very recent GPUs can handle textures up to 16384x16384 pixels.

2.3 Vanilla skyboxes

Name	Description
overworld	This will show the overworld's skybox.
end	This will show the end's skybox.

"type": "overworld"

3. Color

This is exclusive to- and is a requirement when using the monocolor type of skybox.

Name	Description	Required	Default
red	Specifies the amount of red color to be used. Must be a value between 0 and 1.	✔️	-
green	Specifies the amount of green color to be used. Must be a value between 0 and 1.	✔️	-
blue	Specifies the amount of blue color to be used. Must be a value between 0 and 1.	✔️	-
alpha	Specifies the amount of alpha transparency to be used. Must be a value between 0 and 1.	❌	1.0

"color": {"red": 0.84, "green": 0.91, "blue": 0.72, "alpha": 1.0}

4. Texture

This is exclusive to- and is a requirement for the two non-animated skybox types.

Name	Description
texture	Used for the single-sprite-square-textured skybox type. Specifies the directory for the texture file.
textures	Used for the square-textured skybox type. Specifies the directory for the texture files to be used for the top, bottom, east, west, north and south sides of the skybox.

"texture": "fabricskyboxes:sky/skybox.png"

OR

"textures": {
  "top": "fabricskyboxes:sky/skybox_top.png",
  "bottom": "fabricskyboxes:sky/skybox_bottom.png",
  "east": "fabricskyboxes:sky/skybox_east.png",
  "west": "fabricskyboxes:sky/skybox_west.png",
  "north": "fabricskyboxes:sky/skybox_north.png",
  "south": "fabricskyboxes:sky/skybox_south.png"
}

5. Animations

This is exclusive to- and is a requirement for the multi-texture skybox type. You can incorporate as many animations as needed.

The animation texture will cycle through within the designated animation area, determined by the UV ranges. The number of steps in the cycle is defined by the number of rows and columns on the animation texture.

Name	Description	Required
texture	Specifies the location of the texture to be used when rendering the animation	✔️
uvRanges	Specifies the location in UV ranges to render the animation	✔️
gridColumns	Specifies the amount of columns the animation texture has	✔️
gridRows	Specifies the amount of rows the animation texture has	✔️
duration	Specifies the default duration of each animation frame in milliseconds	✔️
frameDuration	Specifies the specific duration per animation frame, which overrides duration	❌

Example for a skybox with 2 animations

"animations": [
  {
    "texture": "fabricskyboxes:/sky/anim_texture_1.png",
    "uvRanges": {
      "minU": 0.25,
      "minV": 0.25,
      "maxU": 0.5,
      "maxV": 0.5
    },
    "gridColumns": 2,
    "gridRows": 4,
    "duration": 50,
    "frameDuration": {"1": 20, "5": 10}
  },
  {
    "texture": "fabricskyboxes:/sky/anim_texture_2.png",
    "uvRanges": {
      "minU": 0.3333,
      "minV": 0.6666,
      "maxU": 0.2,
      "maxV": 0.4
    },
    "gridColumns": 3,
    "gridRows": 5,
    "duration": 10,
    "frameDuration": {"1": 30, "5": 40}
  }
]

5.1 UV ranges

Specifies a UV range object for defining texture coordinates. All fields are required.

Name	Description
minU	Specifies the minimum U coordinate
minV	Specifies the minimum V coordinate
maxU	Specifies the maximum U coordinate
maxV	Specifies the maximum V coordinate

The UV map uses the 3:2 aspect ratio skybox template, as shown in the example below. It is worth noting, that the aspect ratio of your animated area does not necessarily need to match the aspect ratio of the frames in your animation texture. This means, that your frames will be stretched to fit the animation area, even if the aspect ratios do not match. As an example, if your frame is a perfect square, but your animated area is a rectangle, your frame will appear stretched.

5.2 Frame duration

Overrides the default duration of each frame that is set by duration, allowing unique duration for each frame in the animation. All fields are optional. The total number of frames specified should not exceed the number of frames included on the animation texture.

Name	Description
1	Specifies the duration of the 1st animation frame in milliseconds
2	Specifies the duration of the 2nd animation frame in milliseconds
3	Specifies the duration of the 3rd animation frame in milliseconds
4	Specifies the duration of the 4th animation frame in milliseconds

6. Animation textures

This is exclusive to and a requirement for the two animated skybox types. Depending on the chosen skybox type, you will need to specify the textures differently.

Below is an example for animated-square-textured skyboxes, using a 3-frame animation as an example.

"animationTextures": [
  {
    "top": "fabricskyboxes:sky/skybox_frame1_top.png",
    "bottom": "fabricskyboxes:sky/skybox_frame1_bottom.png",
    "east": "fabricskyboxes:sky/skybox_frame1_east.png",
    "west": "fabricskyboxes:sky/skybox_frame1_west.png",
    "north": "fabricskyboxes:sky/skybox_frame1_north.png",
    "south": "fabricskyboxes:sky/skybox_frame1_south.png"
  },
  {
    "top": "fabricskyboxes:sky/skybox_frame2_top.png",
    "bottom": "fabricskyboxes:sky/skybox_frame2_bottom.png",
    "east": "fabricskyboxes:sky/skybox_frame2_east.png",
    "west": "fabricskyboxes:sky/skybox_frame2_west.png",
    "north": "fabricskyboxes:sky/skybox_frame2_north.png",
    "south": "fabricskyboxes:sky/skybox_frame2_south.png"
  },
  {
    "top": "fabricskyboxes:sky/skybox_frame3_top.png",
    "bottom": "fabricskyboxes:sky/skybox_frame3_bottom.png",
    "east": "fabricskyboxes:sky/skybox_frame3_east.png",
    "west": "fabricskyboxes:sky/skybox_frame3_west.png",
    "north": "fabricskyboxes:sky/skybox_frame3_north.png",
    "south": "fabricskyboxes:sky/skybox_frame3_south.png"
  }
]

And for the single-sprite-animated-square-textured skybox type.

"animationTextures": [
  "fabricskyboxes:sky/skybox_frame1.png",
  "fabricskyboxes:sky/skybox_frame2.png",
  "fabricskyboxes:sky/skybox_frame3.png"
]

7. FPS

This is exclusive to- and a requirement for the two animated skybox types.

Name	Description
fps	Specifies the number of frames to be rendered per second.

"fps": 1

8. Blend

Specifies how the skybox should blend with the previously rendered sky layer, the vanilla skybox being the first layer. All fields are optional.

In FabricSkyboxes, the blending of textured skyboxes is achieved using glBlendFunc. The provided blending types serve as presets, utilizing the same equations outlined below for the custom type. For decorations, the blending used aligns with the vanilla game's approach, particularly for the sun and moon blending.

Name	Description	Default
type	Specifies the type of the blend for the skybox only. Valid types are: add, subtract, multiply, screen, replace, alpha, dodge, burn, darken, lighten, decorations, disable and custom.	add
blender	only use this when using the custom blend type

"blend": {
  "type" : "alpha"
}

OR

"blend": {
  "type" : "custom",
  "blender": {
    "sFactor": 0,
    "dFactor": 769,
    "equation": 32774,
    "redAlphaEnabled": true,
    "greenAlphaEnabled": true,
    "blueAlphaEnabled": true,
    "alphaEnabled": false
  }
}

Name	Description	Default
sFactor	Specifies the OpenGL source factor to use.
dFactor	Specifies the OpenGL destination factor to use.
equation	Specifies the OpenGL blend equation to use.
redAlphaEnabled	Specifies whether alpha state will be used in red shader color or predetermined value of 1.0.	false
greenAlphaEnabled	Specifies whether alpha state will be used in green shader color or predetermined value of 1.0.	false
blueAlphaEnabled	Specifies whether alpha state will be used in blue shader color or predetermined value of 1.0.	false
alphaEnabled	Specifies whether alpha state will be used in shader color or predetermined value of 1.0.	false

More information on custom blend can be found in the blend documentation.

9. Properties

Specifies common properties used by all types of skyboxes.

Name	Description	Required	Default
priority	Specifies the order which skybox will be rendered. If there are multiple skyboxes with identical priority, those skyboxes are not re-ordered therefore being dependant of Vanilla's alphabetical namespaced identifier's loading.	❌	0
fade	Specifies the time of day in ticks that the skybox should start and end fading in and out.	✔️	-
rotation	Specifies the rotation speed and angles of the skybox.	❌	[0,0,0] for static/axis/timeShift, 0 for rotationSpeedX/Y/Z, true for skyboxRotation
transitionInDuration	Specifies the duration in ticks that skybox will fade in when valid conditions are changed. The value must be within 1 and 8760000 (365 days * 24000 ticks).	❌	20
transitionOutDuration	Specifies the duration in ticks that skybox will fade out when valid conditions are changed. The value must be within 1 and 8760000 (365 days * 24000 ticks).	❌	20
changeFog	Specifies whether the skybox should change the fog color.	❌	false
fogColors	Specifies the colors to be used for rendering fog. Only has an effect if changeFog is true.	❌	0 for each RGB value
sunSkyTint	Specifies whether the skybox should disable sunrise/set sky color tinting.	❌	true
inThickFog	Specifies whether the skybox should be rendered in thick fog.	❌	true
minAlpha	Specifies the minimum value that the alpha can be. The value must be within 0 and 1.	❌	0.0
maxAlpha	Specifies the maximum value that the alpha can be. The value must be within 0 and 1.	❌	1.0

"properties": {
  "priority": 1,
  "fade": {
    "startFadeIn": 1000,
    "endFadeIn": 2000,
    "startFadeOut": 3000,
    "endFadeOut": 4000,
    "alwaysOn": false
  },
  "rotation": {
    "rotationSpeedY": 0.866,
    "static": [0.0, 0.0, 0.0],
    "axis": [0.0, -180.0, 0.0],
    "timeShift": [0, 0, 0],
    "skyboxRotation": true
  },
  "transitionInDuration": 200,
  "transitionOutDuration": 300,
  "changeFog": true,
  "fogColors": {"red": 0.84, "green": 0.91, "blue": 0.97, "alpha": 1.0},
  "sunSkyTint": true,
  "inThickFog": true,
  "minAlpha": 0.1,
  "maxAlpha": 0.9
}

As you can see, fade, rotation (and its static, axis and timeShift components) have multiple object within, so let's take a look at those in more detail. For fogColors, refer to Color for the specification.

9.1 Fade object

Stores a list of four integers which specify the time in ticks to start and end fading the skybox in and out.

Name	Description	Required	Default
startFadeIn	The time in ticks when a skybox will start to fade in.	✔️ | ❌	-
endFadeIn	The time in ticks when a skybox will end fading in.	✔️ | ❌	-
startFadeOut	The time in ticks when a skybox will start to fade out.	✔️ | ❌	-
endFadeOut	The time in ticks when a skybox will end fading out.	✔️ | ❌	-
alwaysOn	Whether the skybox should always be at full visibility.	❌ | ✔️	false

Fade and alwaysOn can be use exclusively.

Conversion table:

Time in Ticks	Clock Time
0	6 AM
6000	12 AM
12000	6 PM
24000	12 PM

9.2 Rotation Object

Specifies the speed, static- and axis of rotation for a skybox as well as its timeshift. This object is used by both Properties and Decorations. Properties only affects the skybox rotation, and Decorations only affect the sun, moon and stars rotation. All fields are optional.

Name	Description	Default
static	Specifies the static rotation in degrees	[0,0,0]
axis	Specifies the axis rotation in degrees	[0,0,0]
timeShift	Specifies the time shifted for rotation	[0,0,0] (integers only)
rotationSpeedX/Y/Z	Specifies the speed of the skybox rotation around the X, Y or Z axis, in rotations per 24000 ticks	0
skyboxRotation	During sunset/rise, the rotation speed for the sun/moon will slow down/speed up. This object can toggle this behavior.	true for properties, false for decorations

Static is a mapping option, which allows you to reorient your skybox's default position. For example, you can flip your skybox upside down using static. The axis refers to the actual axis, which the skybox will visibly revolve around. The speed parameter determines how many full rotations the sky makes in a single in-game day.

timeShift facilitates synchronization between the skyboxes utilized by both FabricSkyBoxes and OptiFine. By default, FabricSkyBoxes initiates rotation at 0 tick time, whereas OptiFine begins at 18000 tick time.

skyboxRotation becomes noticeable when the time is set to 12000 or 0. During sunrise and sunset, the sun/moon will be slightly above the horizon. This represents the default behavior for decorations when skyboxRotation is set to false. If set to true, the sun/moon will align exactly with the horizon line at times 12000 and 0. This adjustment ensures that the rotation parameters function similarly for both the skyboxes and the sun/moon, enhancing the reliability of rotation configuration.

9.3 Float vector

Specifies a list of three floating-point literals to represent degrees of rotation.

To get a better understanding on how to define these degrees for static and axis, take a look at the image below.

Additionally, a Blender tool has been developed courtesy of @UsernameGeri, allowing real-time visualization and adjustment of both static rotation and axis, providing insights into their impact on the skybox's rotation. This tool is compatible with both FabricSkyBoxes and OptiFine.

Instructions for the tool are documented within the blend file. Only the most basic Blender skills are required to utilize this tool, such as navigating the interface and selecting and rotating objects.

Blender is a free, open source software. Download at https://www.blender.org/

10. Conditions

Specifies when and where a skybox should render. All fields are optional.

Name	Description
worlds	Specifies a list of worlds sky effects that the skybox should be rendered in.
dimensions	Specifies a list of dimension that the skybox should be rendered in.
weather	Specifies a list of weather conditions that the skybox should be rendered in. Valid entries are clear, rain, rain_biome, thunder and snow.
biomes	Specifies a list of biomes that the skybox should be rendered in.
xRanges	Specifies a list of coordinates that the skybox should be rendered between.
yRanges	Specifies a list of coordinates that the skybox should be rendered between.
zRanges	Specifies a list of coordinates that the skybox should be rendered between.
loop	Specifies the loop object that the skybox should be rendered between.
effects	Specifies a list of player status effects during which the skybox should be rendered.

The difference between rain and rain_biome will be apparent in a desert for example. Here, when it rains in the world, a sky using rain_biome will not be visible, whereas one using rain will be. This is to allow to differentiate between biomes where it actually rains, and where it doesn't during weather.

"conditions": {
  "worlds": ["minecraft:overworld"],
  "dimensions": ["my_datapack:custom_world"],
  "weather": ["rain", "thunder"],
  "biomes": ["plains", "forest", "river"],
  "xRanges": [{"min": -100.0, "max": 100.0}],
  "yRanges": [{"min": -128.0, "max": 150.0}, {"min": 200.0, "max": 320.0}],
  "zRanges": [{"min": -150.0, "max": 150.0}],
  "loop": {"days": 8, "ranges": [{"min": 0, "max": 4}, {"min": 5, "max": 8}]},
  "effects": ["minecraft:jump_boost", "minecraft:speed", "minecraft:slowness"]
}

Similarly to Properties, some conditions have multiple objects within. Let's take a look at them.

10.1 MinMax Entry Object

These objects are used by the x-y-z range objects, and the loop object. Multiple MinMax entries can be specified within one range.

Name	Description
min	Specifies the minimum value, inclusive
max	Specifies the maximum value, exclusive

These MinMax ranges should be thought of as sections on a number line, rather than incremental steps, like blocks in Minecraft. This means, that you can specify them to a decimal point precision.

To show a concrete example, let's take a look at the day ranges of a loop object.

"loop": {
  "days": 8,
  "ranges": [{"min": 0, "max": 4}, {"min": 5, "max": 8}]
}

For the purposes of x-y-z ranges, this means that if you want 2 skyboxes to transition when crossing a certain coordinate threshold, you will need to look out for a "gap", as seen in the image above. To avoid this gap, where no sky is shown, you will need to specify the ranges something like this:

sky1.json

"yRanges": [
  {"min": -128.0, "max": 150.0}
]

sky2.json

"yRanges": [
  {"min": 150.0001, "max": 200.0}
]

The reason why we don't write "min": 150.0 in sky2.json, is because then both sky 1 and 2 would overlap and show when standing on Y=150. This peculiarity is really only noticeable on the Y coordinate, as it is easy to align the player on exact whole coordinates, but it can also happen on the X and Z coordinates as well, it's just less likely. Even with the method show above, there is still a gap in-between the 2 skyboxes, but it's very unlikely you will manage to align the player that precisely.

10.2 Loop object

Name	Description
days	Specifies the length of the loop in days.
ranges	Specifies the days where the skybox is rendered.

The loop object's start and end points are determined by the fade times in the given skybox. The loop starts at startFadeIn, and ends at endFadeOut after the specified number of days. To give a concrete example, let's use these parameters:

"properties": {
  "fade": {
    "startFadeIn": 1000,
    "endFadeIn": 2000,
    "startFadeOut": 3000,
    "endFadeOut": 4000
  }
},
"conditions": {
  "loop": {
    "days": 8,
    "ranges": [{"min": 0, "max": 4}, {"min": 5, "max": 8}]
  }
}

In this scenario, the loop starts at /time set 1000. Then if we /time add 195000 (8×24000+(4000-1000)), that is when the loop will end, and it will start again the next day at time 1000.

See also MinMax Entry Object for examples on the implementation.

11. Decorations

Stores all specifications for the stars, sun and moon configuration. For optimal results, the moon texture should use the same layout as the vanilla moon texture. The Default value stores the overworld sun and moon textures and sets all enabled to true. All fields are optional.

Name	Description	Default
blend	Specifies the type of the blend or the decorations only. Valid types are: add, subtract, multiply, screen, replace, alpha, dodge, burn, darken, lighten, decorations and disable.	decorations
sun	Specifies the location of the texture to be used for rendering the sun.	Default sun texture (minecraft:textures/environment/sun.png)
moon	Specifies the location of the texture to be used for rendering the moon.	Default moon texture (minecraft:textures/environment/moon_phases.png)
showSun	Specifies whether the sun should be rendered.	true
showMoon	Specifies whether the moon should be rendered.	true
showStars	Specifies whether stars should be rendered.	true
rotation	Specifies the rotation of the decorations.	[0,0,0] for static/axis/timeShift, 0 for rotationSpeedX/Y/Z, false for skyboxRotation

"decorations": {
  "blend": {"type": "decorations"},
  "sun": "minecraft:textures/environment/sun.png",
  "moon": "minecraft:textures/environment/moon_phases.png",
  "showSun": true,
  "showMoon": true,
  "showStars": true,
  "rotation": {
    "rotationSpeedX": 0.5,
    "static": [0.0, 0.0, 0.0],
    "axis": [0.0, 0.0, 90.0],
    "timeShift": [0, 0, 0],
    "skyboxRotation": false
  }
}

Rotation in Decorations only affects the sun, moon and stars, and not the skybox. To see how to implement the rotation, check Rotation Object and Float Vector.

It is worth knowing, that it is possible to specify unique rotation and blending mode for the sun, moon and stars all individually, if they are set to show true in 3 separate json files, and the other 2 decorations are set to show false. You can also add multiple suns and moon with different blending and/or rotation, if you assign them to multiple different sky layers.

Examples and templates

monocolor

{
	"schemaVersion": 2,
	"type": "monocolor",
	"color": {"red": 0.84, "green": 0.91, "blue": 0.72, "alpha": 1.0},
	"blend": {"type" : "add"},
	"properties": {
		"priority": 1,
		"fade": {
			"startFadeIn": 1000,
			"endFadeIn": 2000,
			"startFadeOut": 3000,
			"endFadeOut": 4000,
			"alwaysOn": false
			},
		"rotation": {
			"rotationSpeedY": 0.0,
			"static": [0.0, 0.0, 0.0],
			"axis": [0.0, -180.0, 0.0]
		},
		"transitionInDuration": 200,
		"transitionOutDuration": 300,
		"changeFog": true,
		"fogColors": {"red": 0.84, "green": 0.91, "blue": 0.97, "alpha": 1.0},
		"sunSkyTint": true,
		"inThickFog": true,
		"maxAlpha": 0.9
	},
	"conditions": {
		"worlds": ["minecraft:overworld"],
		"dimensions": ["my_datapack:custom_world"],
		"weather": ["rain", "thunder"],
		"biomes": ["plains", "forest", "river"],
		"xRanges": [{"min": -100.0, "max": 100.0}],
		"yRanges": [{"min": -128.0, "max": 150.0}, {"min": 200.0, "max": 320.0}],
		"zRanges": [{"min": -150.0, "max": 150.0}],
		"loop": {
			"days": 8,
			"ranges": [{"min": 0, "max": 4}, {"min": 5, "max": 8}]
		},
		"effects": ["minecraft:jump_boost", "minecraft:speed", "minecraft:slowness"]
	},
	"decorations": {
		"blend": {"type" : "add"},
		"sun": "minecraft:textures/environment/sun.png",
		"moon": "minecraft:textures/environment/moon_phases.png",
		"showSun": true,
		"showMoon": true,
		"showStars": true,
		"rotation": {
			"rotationSpeedX": 0.5,
			"static": [0.0, 0.0, 0.0],
			"axis": [0.0, 0.0, 90.0]
		}
	}
}

square-textured

{
	"schemaVersion": 2,
	"type": "square-textured",
	"textures": {
		"top": "fabricskyboxes:sky/skybox_top.png",
		"bottom": "fabricskyboxes:sky/skybox_bottom.png",
		"east": "fabricskyboxes:sky/skybox_east.png",
		"west": "fabricskyboxes:sky/skybox_west.png",
		"north": "fabricskyboxes:sky/skybox_north.png",
		"south": "fabricskyboxes:sky/skybox_south.png"
	},
	"blend": {"type" : "alpha"},
	"properties": {
		"priority": 1,
		"fade": {
			"startFadeIn": 1000,
			"endFadeIn": 2000,
			"startFadeOut": 3000,
			"endFadeOut": 4000,
			"alwaysOn": false
			},
		"rotation": {
			"rotationSpeedY": 0.866,
			"static": [0.0, 0.0, 0.0],
			"axis": [0.0, -180.0, 0.0]
		},
		"transitionInDuration": 200,
		"transitionOutDuration": 300,
		"changeFog": true,
		"fogColors": {"red": 0.84, "green": 0.91, "blue": 0.97, "alpha": 1.0},
		"sunSkyTint": true,
		"inThickFog": true,
		"maxAlpha": 0.9
	},
	"conditions": {
		"worlds": ["minecraft:overworld"],
		"dimensions": ["my_datapack:custom_world"],
		"weather": ["rain", "thunder"],
		"biomes": ["plains", "forest", "river"],
		"xRanges": [{"min": -100.0, "max": 100.0}],
		"yRanges": [{"min": -128.0, "max": 150.0}, {"min": 200.0, "max": 320.0}],
		"zRanges": [{"min": -150.0, "max": 150.0}],
		"loop": {
			"days": 8,
			"ranges": [{"min": 0, "max": 4}, {"min": 5, "max": 8}]
		},
		"effects": ["minecraft:jump_boost", "minecraft:speed", "minecraft:slowness"]
	},
	"decorations": {
		"blend": {"type" : "screen"},
		"sun": "minecraft:textures/environment/sun.png",
		"moon": "minecraft:textures/environment/moon_phases.png",
		"showSun": true,
		"showMoon": true,
		"showStars": true,
		"rotation": {
			"rotationSpeedX": 0.5,
			"static": [0.0, 0.0, 0.0],
			"axis": [0.0, 0.0, 90.0]
		}
	}
}

single-sprite-square-textured

{
	"schemaVersion": 2,
	"type": "single-sprite-square-textured",
	"texture": "fabricskyboxes:sky/skybox.png",
	"blend": {"type" : "alpha"},
	"properties": {
		"priority": 1,
		"fade": {
			"startFadeIn": 1000,
			"endFadeIn": 2000,
			"startFadeOut": 3000,
			"endFadeOut": 4000,
			"alwaysOn": false
			},
		"rotation": {
			"rotationSpeedZ": 0.866,
			"static": [0.0, 0.0, 0.0],
			"axis": [0.0, -180.0, 0.0]
		},
		"transitionInDuration": 200,
		"transitionOutDuration": 300,
		"changeFog": true,
		"fogColors": {"red": 0.84, "green": 0.91, "blue": 0.97, "alpha": 1.0},
		"sunSkyTint": true,
		"inThickFog": true,
		"maxAlpha": 0.9
	},
	"conditions": {
		"worlds": ["minecraft:overworld"],
		"dimensions": ["my_datapack:custom_world"],
		"weather": ["rain", "thunder"],
		"biomes": ["plains", "forest", "river"],
		"xRanges": [{"min": -100.0, "max": 100.0}],
		"yRanges": [{"min": -128.0, "max": 150.0}, {"min": 200.0, "max": 320.0}],
		"zRanges": [{"min": -150.0, "max": 150.0}],
		"loop": {
			"days": 8,
			"ranges": [{"min": 0, "max": 4}, {"min": 5, "max": 8}]
		},
		"effects": ["minecraft:jump_boost", "minecraft:speed", "minecraft:slowness"]
	},
	"decorations": {
		"blend": {"type" : "screen"},
		"sun": "minecraft:textures/environment/sun.png",
		"moon": "minecraft:textures/environment/moon_phases.png",
		"showSun": true,
		"showMoon": true,
		"showStars": true,
		"rotation": {
			"rotationSpeedY": 0.5,
			"static": [0.0, 0.0, 0.0],
			"axis": [0.0, 0.0, 90.0]
		}
	}
}

animated-square-textured

{
	"schemaVersion": 2,
	"type": "animated-square-textured",
	"animationTextures": [
		{
			"top": "fabricskyboxes:sky/skybox_frame1_top.png",
			"bottom": "fabricskyboxes:sky/skybox_frame1_bottom.png",
			"east": "fabricskyboxes:sky/skybox_frame1_east.png",
			"west": "fabricskyboxes:sky/skybox_frame1_west.png",
			"north": "fabricskyboxes:sky/skybox_frame1_north.png",
			"south": "fabricskyboxes:sky/skybox_frame1_south.png"
		},
		{
			"top": "fabricskyboxes:sky/skybox_frame2_top.png",
			"bottom": "fabricskyboxes:sky/skybox_frame2_bottom.png",
			"east": "fabricskyboxes:sky/skybox_frame2_east.png",
			"west": "fabricskyboxes:sky/skybox_frame2_west.png",
			"north": "fabricskyboxes:sky/skybox_frame2_north.png",
			"south": "fabricskyboxes:sky/skybox_frame2_south.png"
		},
		{
			"top": "fabricskyboxes:sky/skybox_frame3_top.png",
			"bottom": "fabricskyboxes:sky/skybox_frame3_bottom.png",
			"east": "fabricskyboxes:sky/skybox_frame3_east.png",
			"west": "fabricskyboxes:sky/skybox_frame3_west.png",
			"north": "fabricskyboxes:sky/skybox_frame3_north.png",
			"south": "fabricskyboxes:sky/skybox_frame3_south.png"
		}
	],
	"fps": 4,
	"blend": {"type" : "alpha"},
	"properties": {
		"priority": 1,
		"fade": {
			"startFadeIn": 1000,
			"endFadeIn": 2000,
			"startFadeOut": 3000,
			"endFadeOut": 4000,
			"alwaysOn": false
			},
		"rotation": {
			"rotationSpeedX": 0.866,
			"static": [0.0, 0.0, 0.0],
			"axis": [0.0, -180.0, 0.0]
		},
		"transitionInDuration": 200,
		"transitionOutDuration": 300,
		"changeFog": true,
		"fogColors": {"red": 0.84, "green": 0.91, "blue": 0.97, "alpha": 1.0},
		"sunSkyTint": true,
		"inThickFog": true,
		"maxAlpha": 0.9
	},
	"conditions": {
		"worlds": ["minecraft:overworld"],
		"dimensions": ["my_datapack:custom_world"],
		"weather": ["rain", "thunder"],
		"biomes": ["plains", "forest", "river"],
		"xRanges": [{"min": -100.0, "max": 100.0}],
		"yRanges": [{"min": -128.0, "max": 150.0}, {"min": 200.0, "max": 320.0}],
		"zRanges": [{"min": -150.0, "max": 150.0}],
		"loop": {
			"days": 8,
			"ranges": [{"min": 0, "max": 4}, {"min": 5, "max": 8}]
		},
		"effects": ["minecraft:jump_boost", "minecraft:speed", "minecraft:slowness"]
	},
	"decorations": {
		"blend": {"type" : "add"},
		"sun": "minecraft:textures/environment/sun.png",
		"moon": "minecraft:textures/environment/moon_phases.png",
		"showSun": true,
		"showMoon": true,
		"showStars": true,
		"rotation": {
			"rotationSpeedZ": 0.5,
			"static": [0.0, 0.0, 0.0],
			"axis": [0.0, 0.0, 90.0]
		}
	}
}

single-sprite-animated-square-textured

{
	"schemaVersion": 2,
	"type": "single-sprite-animated-square-textured",
	"animationTextures": [
		"fabricskyboxes:sky/skybox_frame1.png",
		"fabricskyboxes:sky/skybox_frame2.png",
		"fabricskyboxes:sky/skybox_frame3.png"
	],
	"fps": 4,
	"blend": {"type" : "alpha"},
	"properties": {
		"priority": 1,
		"fade": {
			"startFadeIn": 1000,
			"endFadeIn": 2000,
			"startFadeOut": 3000,
			"endFadeOut": 4000,
			"alwaysOn": false
			},
		"rotation": {
			"rotationSpeedY": 0.866,
			"static": [0.0, 0.0, 0.0],
			"axis": [0.0, -180.0, 0.0]
		},
		"transitionInDuration": 200,
		"transitionOutDuration": 300,
		"changeFog": true,
		"fogColors": {"red": 0.84, "green": 0.90, "blue": 0.97, "alpha": 1.0},
		"sunSkyTint": true,
		"inThickFog": true,
		"maxAlpha": 0.9
	},
	"conditions": {
		"worlds": ["minecraft:overworld"],
		"dimensions": ["my_datapack:custom_world"],
		"weather": ["rain", "thunder"],
		"biomes": ["plains", "forest", "river"],
		"xRanges": [{"min": -100.0, "max": 100.0}],
		"yRanges": [{"min": -128.0, "max": 150.0}, {"min": 200.0, "max": 320.0}],
		"zRanges": [{"min": -150.0, "max": 150.0}],
		"loop": {
			"days": 8,
			"ranges": [{"min": 0, "max": 4}, {"min": 5, "max": 8}]
		},
		"effects": ["minecraft:jump_boost", "minecraft:speed", "minecraft:slowness"]
	},
	"decorations": {
		"blend": {"type" : "screen"},
		"sun": "minecraft:textures/environment/sun.png",
		"moon": "minecraft:textures/environment/moon_phases.png",
		"showSun": true,
		"showMoon": true,
		"showStars": true,
		"rotation": {
			"rotationSpeedZ": 0.5,
			"static": [0.0, 0.0, 0.0],
			"axis": [0.0, 0.0, 90.0]
		}
	}
}

multi-texture

{
	"schemaVersion": 2,
	"type": "multi-texture",
	"animations": [
		{
			"texture": "fabricskyboxes:sky/animation.png",
			"uvRanges": {
				"minU": 0.416666666,
				"minV": 0.5,
				"maxU": 0.583333333,
				"maxV": 0.75
			},
			"gridColumns": 2,
			"gridRows": 3,
			"duration": 500
		}
	],
	"blend": {"type" : "alpha"},
	"properties": {
		"priority": 1,
		"fade": {
			"startFadeIn": 1000,
			"endFadeIn": 2000,
			"startFadeOut": 3000,
			"endFadeOut": 4000,
			"alwaysOn": false
			},
		"rotation": {
			"rotationSpeedZ": 0.866,
			"static": [0.0, 0.0, 0.0],
			"axis": [0.0, -180.0, 0.0]
		},
		"transitionInDuration": 200,
		"transitionOutDuration": 300,
		"changeFog": true,
		"fogColors": {"red": 0.84, "green": 0.91, "blue": 0.97, "alpha": 1.0},
		"sunSkyTint": true,
		"inThickFog": true,
		"maxAlpha": 0.9
	},
	"conditions": {
		"worlds": ["minecraft:overworld"],
		"dimensions": ["my_datapack:custom_world"],
		"weather": ["rain", "thunder"],
		"biomes": ["plains", "forest", "river"],
		"xRanges": [{"min": -100.0, "max": 100.0}],
		"yRanges": [{"min": -128.0, "max": 150.0}, {"min": 200.0, "max": 320.0}],
		"zRanges": [{"min": -150.0, "max": 150.0}],
		"loop": {
			"days": 8,
			"ranges": [{"min": 0, "max": 4}, {"min": 5, "max": 8}]
		},
		"effects": ["minecraft:jump_boost", "minecraft:speed", "minecraft:slowness"]
	},
	"decorations": {
		"blend": {"type" : "screen"},
		"sun": "minecraft:textures/environment/sun.png",
		"moon": "minecraft:textures/environment/moon_phases.png",
		"showSun": true,
		"showMoon": true,
		"showStars": true,
		"rotation": {
			"rotationSpeedY": 0.5,
			"static": [0.0, 0.0, 0.0],
			"axis": [0.0, 0.0, 90.0]
		}
	}
}