block.properties

The block.properties file (located in the shaders folder) lets you assign IDs to specific blocks/block entities by their Minecraft ID. These IDs can be read through mc_Entity and blockEntityId respectively in gbuffers and shadow shaders. The block.properties file should be placed in the shaders folder.

Blocks and block entities can be assigned to an ID in this file, with the following syntax:

block.<ID> = [<namespace>:]<block_id>[:<NBT_tag>=<value>]

# for example
block.5 = stone minecraft:oak_trapdoor:open=true

The optional namespace allows support for modded blocks/block entities. Multiple blocks/block entities can be assigned to a single ID, however a single block/block entity can only be assigned to a single ID. IDs are stored internally as 16-bit signed integers, and can store values between -32768 and 32767.

NBT’s can optionally be specified with the <NBT_tag>=<value> format. They can be used to specify specific states for some blocks, for example redstone which is on/off, orientation for slabs/stairs, etc. For more info on NBT’s, see the Minecraft Wiki.

Data Pack Tags

Iris 1.7 adds support for data pack tags, which allow assigning groups of block based on attributes of the block. For more info on tags, see the Minecraft Wiki.

To specify a tag, use the following syntax %<tag> instead of the old block ID syntax. Use the IRIS_TAG_SUPPORT macro in block.properties to detect if the current version of Iris supports tags:

#ifdef IRIS_TAG_SUPPORT
  block.<ID> = %[<namespace>:]<tag>
#endif

# for example
#ifdef IRIS_TAG_SUPPORT
  block.9 = %minecraft:leaves %logs
#endif