feat: directives/uniforms: add iris exclusive directives

src/content/docs/reference/Directives/Constants/entityShadowDistanceMul.mdx

@@ -0,0 +1,16 @@
+---
+title: entityShadowDistanceMul
+description: entityShadowDistanceMul
+sidebar:
+  label: entityShadowDistanceMul
+  order: 3
+  badge:
+    text: Iris Only
+    variant: tip
+---
+
+### `const float entityShadowDistanceMul = 1.0;`
+
+#### Location: composite, deferred, final, prepare
+
+This value controls the bounds for entity shadows to be rendered. By default, it is the value set for terrain. Any floating point number that is not 1 is multiplied by the terrain distance to get the final shadow distance multiplier.

src/content/docs/reference/Directives/Constants/voxelDistance.mdx

@@ -0,0 +1,18 @@
+---
+title: voxelDistance
+description: voxelDistance
+sidebar:
+  label: voxelDistance
+  order: 3
+  badge:
+    text: Iris Only
+    variant: tip
+---
+
+### `const float voxelDistance = 160.0;`
+
+#### Location: composite, deferred, final, prepare
+
+Setting [`shadow.culling = reversed`](/reference/directives/shadersproperties/shadow_culling) in shaders.properties will create an area around the player where geometry in the shadow pass will not be culled. Outside this area, geometry will be culled as if shadow culling was enabled. This "unculled" distance is controled with `const float voxelDistance`, and the culled distance is controlled as normal with `const float shadowDistance` (and cannot be lower than `voxelDistance`). This feature is intended for packs which utilize both voxelization and a shadow map.
+
+It is also recommended (but not required) to use the feature flag [`REVERSED_CULLING`](/reference/directives/shadersproperties/flags) to avoid compatibility issues with older Iris versions.

src/content/docs/reference/Directives/Shaders.Properties/flags.mdx

@@ -21,7 +21,7 @@ iris.features.optional=BLOCK_EMISSION_ATTRIBUTE ENTITY_TRANSLUCENT SSBO
 
 The following are currently valid options:
 
-`SEPARATE_HARDWARE_SAMPLERS` (required for Separate Hardware Shadow Samplers)
+`SEPARATE_HARDWARE_SAMPLERS` (required for [Separate Hardware Shadow Samplers](/reference/buffers/shadowtex))
 
 `PER_BUFFER_BLENDING`
 
@@ -33,8 +33,8 @@ The following are currently valid options:
 
 `CUSTOM_IMAGES` (required for Custom Images)
 
-`HIGHER_SHADOWCOLOR` (required for Extended Shadowcolor)
+`HIGHER_SHADOWCOLOR` (required for [Extended Shadowcolor](/reference/buffers/shadowcolor))
 
-`REVERSED_CULLING` (recommended, but not required for Reverse Shadow Culling)
+`REVERSED_CULLING` (recommended, but not required for [Reverse Shadow Culling](/reference/directives/constants/voxeldistance))
 
 `BLOCK_EMISSION_ATTRIBUTE` (recommended, but not required for [Block Emission: at_midBlock.w] as of [iris-1.7.0-snapshotmc1.20.4-a787322])

src/content/docs/reference/Directives/Shaders.Properties/particles_ordering.mdx

@@ -0,0 +1,20 @@
+---
+title: particles.ordering
+description: particles.ordering
+sidebar:
+  label: particles.ordering
+  order: 2
+  badge:
+    text: Iris Only
+    variant: tip
+---
+
+### `particles.ordering=<mixed|after|before>`
+
+#### Location: shaders.properties
+
+This controls how particles will be rendered. There are 3 possible options for this value.
+
+- `mixed`: Opaque particles are rendered before the [deferred](/reference/programs/deferred) pass, and translucent particles are rendered after. This is the default if no [deferred](/reference/programs/deferred) passes are present.
+- `after`: All particles are rendered after the [deferred](/reference/programs/deferred) pass. This is the default if there are any [deferred](/reference/programs/deferred) passes.
+- `before`: All particles are rendered before the [deferred](/reference/programs/deferred) pass.

src/content/docs/reference/Directives/Shaders.Properties/separateEntityDraws.mdx

@@ -0,0 +1,16 @@
+---
+title: separateEntityDraws
+description: separateEntityDraws
+sidebar:
+  label: separateEntityDraws
+  order: 2
+  badge:
+    text: Iris Only
+    variant: tip
+---
+
+### `separateEntityDraws=<true|false>`
+
+#### Location: shaders.properties
+
+If `separateEntityDraws` is true in shaders.properties, translucent entities and block entities will wait to be drawn until after the deferred pass, and then will be drawn in the `gbuffers_entities_translucent` and `gbuffers_block_translucent` programs.

src/content/docs/reference/Directives/Shaders.Properties/shadow_culling.mdx

@@ -0,0 +1,15 @@
+---
+title: shadow.culling
+description: shadow.culling
+sidebar:
+  label: shadow.culling
+  order: 2
+---
+
+### `shadow.culling=<true|false|reversed>`
+
+#### Location: shaders.properties
+
+Controls culling in the [`shadow`](/reference/programs/shadow) pass. Enabling it will prevent geometry which would not cast a shadow through the view frustum from rendering. Disabling it will prevent any geometry within the shadow distance from being culled.
+
+Iris adds an additional option, `reversed`, which disables culling within a specific radius of the player as defined in [`voxelDistance`](/reference/directives/constants/voxeldistance), while retaining culling outside of that distance. It is also recommended (but not required) to use the feature flag [`REVERSED_CULLING`](/reference/directives/shadersproperties/flags) to avoid compatibility issues with older Iris versions.

src/content/docs/reference/Directives/Shaders.Properties/shadow_enabled.mdx

@@ -0,0 +1,16 @@
+---
+title: shadow.enabled
+description: shadow.enabled
+sidebar:
+  label: shadow.enabled
+  order: 2
+  badge:
+    text: Iris Only
+    variant: tip
+---
+
+### `shadow.enabled=<true|false>`
+
+#### Location: shaders.properties
+
+Normally Optifine/Iris will check if the shadow buffers are bound and used to determine when to enable/disable the shadow pass. Iris offers an additional explicit control for enabling/disabling the pass. Thic can be useful for voxelization which doesn't write to a [shadowtex](/reference/buffers/shadowtex)/[shadowcolor](/reference/buffers/shadowcolor) buffer (for example SSBOs or custom images).

src/content/docs/reference/Directives/Shaders.Properties/shadow_player.mdx

@@ -0,0 +1,16 @@
+---
+title: shadowPlayer
+description: shadowPlayer
+sidebar:
+  label: shadowPlayer
+  order: 2
+  badge:
+    text: Iris Only
+    variant: tip
+---
+
+### `shadowPlayer=<true|false>`
+
+#### Location: shaders.properties
+
+This value controls if the player should have a shadow rendered. This is forced on if `shadowEntities` (default `true`) is enabled. This also controls shadows of any entities the player is riding.

src/content/docs/reference/Directives/Shaders.Properties/supportsColorCorrection.mdx

@@ -0,0 +1,18 @@
+---
+title: supportsColorCorrection
+description: supportsColorCorrection
+sidebar:
+  label: supportsColorCorrection
+  order: 2
+  badge:
+    text: Iris Only
+    variant: tip
+---
+
+### `supportsColorCorrection=<true|false>`
+
+#### Location: shaders.properties
+
+Iris 1.6.4 added support for additional color spaces beyond sRGB (DCI_P3, Display P3, REC2020, and Adobe RGB). This does not allow for outputting HDR values, it simply applies a tonemapping operation in the given color space instead of sRGB.
+
+By default, Iris will assume all shaders output sRGB, and if a different color spaces is selected it will convert the sRGB output to that color space for display. If `supportsColorCorrection = true` is in shaders.properties however, this conversion will be left up to the shader. In all scenarios, the chosen colorspace is avaliable through the uniform [`currentColorSpace`](/reference/uniforms/general/currentcolorspace).

src/content/docs/reference/Directives/Shaders.Properties/voxelizeLightBlocks.mdx

@@ -0,0 +1,20 @@
+---
+title: voxelizeLightBlocks
+description: voxelizeLightBlocks
+sidebar:
+  label: voxelizeLightBlocks
+  order: 2
+  badge:
+    text: Iris Only
+    variant: tip
+---
+
+### `voxelizeLightBlocks=<true|false>`
+
+#### Location: shaders.properties
+
+Using `voxelizeLightBlocks` in shaders.properties, you can now voxelize light blocks in the shadow or main pass.
+
+This only applies to light blocks ([Minecraft Wiki](https://minecraft.wiki/w/Light_Block)), which are a specific block which is invisible but emits a specific level of light. This does not affect any other blocks or geometry.
+
+Light blocks will be rendered as a single (degenerate) invisible quad with all points centered on the middle of the block. (`at_midBlock` will be 0.) The ID will correspond as normal to the light block, and UV will be 0. `lmcoord.xy` will both be the value of the light made by the light block.

src/content/docs/reference/Uniforms/General/currentRenderedItemId.mdx

@@ -0,0 +1,20 @@
+---
+title: currentRenderedItemId
+description: currentRenderedItemId
+sidebar:
+  label: currentRenderedItemId
+  order: 1
+  badge:
+    text: Iris Only
+    variant: tip
+---
+
+### `uniform int currentRenderedItemId;`
+
+Iris allows detecting items and armor during rendering on *anything*.
+
+Using `uniform int currentRenderedItemId;`, you can detect items and armor rendered in the level at the point of render. This is similar to [`heldItemId`](/reference/uniforms/general/helditemid) and [`heldItemId2`](/reference/uniforms/general/helditemid2), except it applies to the currently rendered item/armor instead of the held item.
+
+There are some new ID's that can be detected alongside items and armor:
+
+`trim_material` to detect armor trims on armor. (For example, `trim_emerald`).