PBR roadmap

[lilleyse]

• Proof-of-concept - Load glTF 1.0 models with hard-coded materials and shaders from https://github.com/khronosGroup/gltf-webgl-pbr. Use the sun as the sole light source.
• Finish up glTF 2.0 support
  • Gltf 2.0 #4808
  • Update version -> 2.0 (#271) gltf-pipeline#272
  • 2.0 pbr gltf-pipeline#274 - the material translation here is good for testing, but will be removed once PBR support is complete.
• Support normal mapping
  • glTF without TANGENT attribute - compute tangent with screen space derivatives if supported
  • glTF with TANGENT attribute - just compute bitangent easily
• Lighting ideas
  • Simple ambient factor
  • Experiment with default environment maps shipped with Cesium
  • Get atmosphere color / ground color
  • Render cube map dynamically
• Handle spec-gloss extension.

@moneimne feel free to add ideas/comments as we go through this. The main first goal is to render with PBR shaders but use the sun as the only light source. After that we can experiment with different light sources like environment maps, atmosphere color, area lights, etc. I'll also add more ideas as we go.

[pjcozzi]

Before exploring Lighting ideas and spec-gloss extension, please do the least amount reasonable to get a full glTF 2.0 implementation working - including morph targets - and merged into master.

[moneimne]

Idea for applying PBR to geospatial: Altering the metallic and roughness of a model at runtime to achieve certain results, For example, one can add highlights or rim lights to a model to represent selection by manipulating the metallic and roughness parameters.

[pjcozzi]

@lilleyse OK to close this? Is there anything left in the roadmap that should perhaps move to #4009?

[lilleyse]

The only thing left unfinished here is Handle spec-gloss extension. so good to close.