Overview: Uniforms

Uniforms are values sent from the CPU, and as such they cannot change from one shader invocation to the next within a render call. Most uniforms provided by Iris are constant across the entire frame, some values change between different geometry (such as renderstage).

Below is an index of all Uniforms available in Iris. Uniforms marked as Iris Exclusive are only available in Iris, and uniforms marked as Optifine CU / Iris are available in Optifine only through custom uniforms but are available anywhere in Iris. Any unmarked uniforms is available in either Optifine or Iris.

Camera/Player

Uniform	Type	Value Range	Description	Tag
cameraPosition	vec3		Position of the camera in world space
eyeAltitude	float		Y coordinate of the player in blocks
cameraPositionFract	vec3	[0,1)	Fractional component of the camera position in world space	Iris Exclusive
cameraPositionInt	ivec3		Integer component of the camera position in world space	Iris Exclusive
previousCameraPosition	vec3		Value of cameraPosition from the previous frame	Iris Exclusive
previousCameraPositionFract	vec3	[0,1)	Value of cameraPositionFract from the previous frame	Iris Exclusive
previousCameraPositionInt	ivec3		Value of cameraPositionInt from the previous frame	Iris Exclusive
eyePosition	vec3		World space position of the player’s head model	Iris Exclusive
relativeEyePosition	vec3		World space offset from the player head to the camera	Iris Exclusive
playerBodyVector	vec3	[0,1]	World aligned direction of player model’s body	Iris Exclusive
playerLookVector	vec3	[0,1]	World aligned direction of player model’s head	Iris Exclusive
upPosition	vec3	[0, 100]	Upwards direction in view space, length of 100
eyeBrightness	ivec2	[0, 240]	Light value at the player’s location: (block, sky)
eyeBrightnessSmooth	ivec2	[0, 240]	eyeBrightness smoothed over time by eyeBrightnessHalfLife
centerDepthSmooth	float	[0,1]	Depth buffer value at the center of the screen, smoothed over time
firstPersonCamera	bool	true / false	Whether the player camera is in first person mode	Iris Exclusive

Player Status

Uniform	Type	Value Range	Description	Tag
isEyeInWater	int	0, 1, 2, 3	Fluid that the camera is currently in
isSpectator	bool	true / false	Whether the player is currently in spectator mode	Iris Exclusive
isRightHanded	bool	true / false	Whether the player’s main hand is set to right hand	Iris Exclusive
blindness	float	[0,1]	Blindness effect multiplier
darknessFactor	float	[0,1]	Strength of the darkness effect
darknessLightFactor	float	[0,1]	Strength of the dimming effect from the darkness status effect
nightVision	float	[0,1]	Night vision effect multiplier
playerMood	float	[0,1]	Player mood value
constantMood	float	[0,1]	playerMood but it doesn’t reset at 1.0	Iris Exclusive
currentPlayerAir	float	[0,1]	Normalized air the player has remaining	Iris Exclusive
maxPlayerAir	float	-1, 300	Maximum player air when underwater	Iris Exclusive
currentPlayerArmor	float	-1, [0,1]	Normalized armor player has equipped	Iris Exclusive
maxPlayerArmor	float	50	Maximum player armor value	Iris Exclusive
currentPlayerHealth	float	-1, [0,1]	Normalized health the player has remaining	Iris Exclusive
maxPlayerHealth	float	-1, [0, 1024]	Maximum player health value	Iris Exclusive
currentPlayerHunger	float	-1, [0,1]	Normalized hunger level of player	Iris Exclusive
maxPlayerHunger	float	20	Maximum player hunger value	Iris Exclusive
is_burning	bool	true / false	Whether the player is currently on fire	Optifine CU / Iris
is_hurt	bool	true / false	Whether the player is currently taking damage	Optifine CU / Iris
is_invisible	bool	true / false	Whether the player is invisible	Optifine CU / Iris
is_on_ground	bool	true / false	Whether the player is currently touching the ground	Optifine CU / Iris
is_sneaking	bool	true / false	Whether the player is currently sneaking	Optifine CU / Iris
is_sprinting	bool	true / false	Whether the player is currently sprinting	Optifine CU / Iris
hideGUI	bool	true / false	Whether the player’s GUI is hidden

Screen/System

Uniform	Type	Value Range	Description	Tag
viewHeight	float	[1,∞)	Height of the game window in pixels
viewWidth	float	[1,∞)	Width of the game window in pixels
aspectRatio	float	(0,∞)	Aspect ratio of the game window
screenBrightness	float	[0,1]	Screen brightness from video settings
frameCounter	int	[0, 720719]	Number of frames since start of program
frameTime	float	(0,∞)	Frame time of the previous frame in seconds
frameTimeCounter	float	[0, 3600)	Running time of the game in seconds
currentColorSpace	int	0, 1, 2, 3, 4	Display color space, controlled through video settings	Iris Exclusive
currentDate	ivec3		System date: (year, month, day)	Iris Exclusive
currentTime	ivec3		System time: (hour, minute, second)	Iris Exclusive
currentYearTime	ivec2		Time since beginning of the year and until the end of the year	Iris Exclusive

ID

Uniform	Type	Value Range	Description	Tag
entityId	int	[0, 65535]	ID of the currently rendering entity (gbuffers_entities)
blockEntityId	int	[-32768, 32767]	ID of the currently rendering block entity (gbuffers_block)
currentRenderedItemId	int	[0,65535]	Item ID of currently rendering item/armor/trim	Iris Exclusive
currentSelectedBlockId	int	[-32768, 32767]	Block ID of block selected by the player	Iris Exclusive
currentSelectedBlockPos	vec3		Player space position of the center of the block selected by the player	Iris Exclusive
heldItemId	int	[0, 65535]	Item ID of the item in the player’s hand
heldItemId2	int	[0, 65535]	Item ID of the item in the player’s offhand
heldBlockLightValue	int	[0,15]	Light value of the item held in the player’s hand
heldBlockLightValue2	int	[0,15]	Light value of the item held in the player’s offhand

World/Weather

Uniform	Type	Value Range	Description	Tag
sunPosition	vec3	[0,100]	Position of the sun in view space, length of 100
moonPosition	vec3	[0,100]	Position of the moon in view space, length of 100
shadowLightPosition	vec3	[0,100]	Position of shadow source in view space, length of 100
sunAngle	float	[0,1]	Angle of the sun within the complete day-night cycle
shadowAngle	float	[0,0.5]	Angle of shadow source (whichever is higher in the sky)
moonPhase	int	[0,7]	Current moon phase
rainStrength	float	[0,1]	Current strength of rain
wetness	float	[0,1]	rainStrength but smoothed over time with wetnessHalfLife
thunderStrength	float	[0,1]	Current strength of thunderstorm	Iris Exclusive
lightningBoltPosition	vec4		Position of a lightning bolt being rendered, or vec4(0.0)	Iris Exclusive
worldTime	int	[0, 23999]	Current in-game time
worldDay	int	[0 - )	Number of in-game days passed

Biome/Dimension

Uniform	Type	Value Range	Description	Tag
biome	int		Biome currently occupied by the player	Optifine CU / Iris
biome_category	int		Category of the biome currently occupied by the player	Optifine CU / Iris
biome_precipitation	int	0, 1, 2	Type of precipitation in the current biome	Optifine CU / Iris
rainfall	float	[0,1]	Rainfall property of the current biome	Optifine CU / Iris
temperature	float		Temperature property of the current biome	Optifine CU / Iris
ambientLight	float	[0,1]	Ambient light property of the current dimension	Iris Exclusive
bedrockLevel	int	[-2032, 2016]	Y coordinate of the bedrock floor in the current dimension	Iris Exclusive
cloudHeight	float		Y coordinate of the vanilla cloud plane	Iris Exclusive
hasCeiling	bool	true / false	Whether the current dimension has a ceiling	Iris Exclusive
hasSkylight	bool	true / false	Whether the current dimension has sky lighting	Iris Exclusive
heightLimit	int	[16, 4064]	Distance from maximum to minimum block heights in current dimension	Iris Exclusive
logicalHeightLimit	int		Logical height of the current dimension	Iris Exclusive

Rendering

Uniform	Type	Value Range	Description	Tag
near	float	0.05	Near clipping plane distance
far	float	(0, - )	Current render distance in blocks
alphaTestRef	float	[0,1]	Cutout alpha discard threshold
chunkOffset	vec3		Chunk offset for terrain model space position
entityColor	vec4	[0,1]	Entity tint color
blendFunc	ivec4		Alpha blending function multipliers: (srcRGB, dstRGB, srcA, dstA)
atlasSize	ivec2	[0, - )	Size of the texture atlas, 0 if not bound
renderStage	int		”Render stage” of the current geometry
fogColor	vec3	[0,1]	Horizon fog color
skyColor	vec3	[0,1]	Upper sky color
fogDensity	float	[0,1]	Relative fog density
fogStart	float	(0, - )	Starting fog distance in blocks
fogEnd	float	(0, - )	Ending fog distance in blocks
fogMode	int	2048, 2049, 2048	Fog type used for vanilla fog
fogShape	int	0,1	Fog shape used for vanilla fog

Matrices

Uniform	Type	Value Range	Description	Tag
gbufferModelView	mat4		Player space to view space in general
gbufferModelViewInverse	mat4		Converts from view space to player space in general
gbufferProjection	mat4		Converts from view space to clip space in general
gbufferProjectionInverse	mat4		Converts from clip/screen to view space in general
shadowModelView	mat4		Converts from player space to shadow view space in general
shadowModelViewInverse	mat4		Converts from shadow view space to player space in general
shadowProjection	mat4		Converts from shadow view space to shadow clip space in general
shadowProjectionInverse	mat4		Converts from shadow clip/screen space to shadow view space in general
gbufferPreviousModelView	mat4		Value of gbufferModelView from the previous frame
gbufferPreviousProjection	mat4		Value of gbufferProjection from the previous frame
modelViewMatrix	mat4		Converts from model space to view space in general
modelViewMatrixInverse	mat4		Converts from view space to model space for current geometry
projectionMatrix	mat4		Converts from view space to clip space for current geometry
projectionMatrixInverse	mat4		Converts from clip/screen space to view space for current geometry
normalMatrix	mat3		Converts normals from model space to view space for current geometry
textureMatrix	mat4		Transforms texture coordinates before sampling