WEBGI_materials_bumpmap glTF Extension

Contributors

Palash Bansal, @repalash

Status

Draft.

Dependencies

Written against the glTF 2.0 spec.

Exclusions

This extension must not be used on a material that also uses KHR_materials_pbrSpecularGlossiness.
This extension must not be used on a material that also uses KHR_materials_unlit.
This extension must not be used on a material that also uses KHR_materials_volume.

Overview

This extension adds support for setting bumpTexture and bumpScale.
bumpTexture sets the bump map from the R channel. The black and white values map to the perceived depth in relation to the lights. Bump doesn’t actually affect the geometry of the object, only the lighting.
bumpScale defines how much the bump map affects the material. Typical ranges are 0-1. Bump map is ignored if bumpScale == 0

Extending Materials

Sample values:

{
    "materials": [
        {
            "extensions": {
                "WEBGI_materials_bumpmap": {
                    "bumpScale": 0.6,
                    "bumpTexture": { "index": 1 },
                }
            }
        }
    ]
}

Implementation details

Basic Implementation similar to three.js: bumpMap in MeshPhysicalMaterial
Alternative implementation with Parallax Bump Mapping.

TODO: add technical details.

Known Implementations

WebGi
- Core Viewer
- Core Editor

Resources

Simple Plane glTF with BumpMap: TODO.
Parallax Mapping plugin sample: https://showcase.pixotronics.com/demos/plugins~parallax-mapping.html (TODO)