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Iris Docs

PBR Standards

Texture packs can optionally provide extra data to Iris through the use of normal and specular maps.

For more information on normal maps and specular maps, check out learnopengl.com.

Access

Normal map textures have the same name as the texture they should be attached to, with the _n suffix. For example, for a block of cobblestone, the texture is called cobblestone.png, and the normal map for cobblestone would be cobblestone_n.png. Likewise, specular maps have the suffix _s, meaning for cobblestone it would be cobblestone_s.png.

These textures are provided in the form of two additional texture atlases.

  • uniform sampler2D normals
  • uniform sampler2D specular

These texture atlases should be sampled in the same way that gtexture is sampled.

Formats

There are two standard formats used for encoding PBR data in the normal and specular maps - oldPBR (also known as seusPBR) and labPBR.

LabPBR

LabPBR is the preferred format for encoding PBR data, specified by shaderLABS. For specifics on the standard, visit the wiki page.

oldPBR (seusPBR)

Note: Most modern resource packs do not use oldPBR.

oldPBR is not a standard format, so much as a general convention that was followed by shader developers prior to the specification of labPBR. It is also known as seusPBR due to the fact that Sonic Ether’s Unbelievable Shaders (a popular series of shaderpacks) do not support labPBR, and thus an oldPBR compatible pack is needed to use with them.

  • The normal is encoded in the rgb components of the normal map.
  • The height is encoded in the a component of the normal map.
  • The smoothness is encoded in the r component of the specular map.
  • The metallness is encoded in the g component of the specular map.
  • The emissiveness is encoded in the b component of the specular map.

Checking the format

A texture pack can optionally declare that it is LabPBR compliant (and the version of the format it uses) in texture.properties by adding something like the following

If labPBR is declared at all, the following preprocessor define will be declared

texture.properties
format=lab-pbr
// this will be defined
MC_TEXTURE_FORMAT_LAB_PBR

Additionally, if a version is specified, a further define will be declared. For example, with version 1.3:

texture.properties
format=lab-pbr/1.3
// this will be defined
MC_TEXTURE_FORMAT_LAB_PBR
MC_TEXTURE_FORMAT_LAB_PBR_1_3

Note: At the time of writing, the only supported LabPBR version is 1.3. Specifying other versions in a texture pack may cause errors.