flowchart TB
  A["hollowcube mesh:<br/>position, normal, colour"] --> B["vertex shader<br/>reads a_texcoord0"]
  B --> C{"bgfx renderer"}
  C -- "D3D12" --> D["input element TEXCOORD0:<br/>float2 at offset 0"]
  D --> E["UV = position x, y:<br/>stone texture on the cubes"]
  E --> F["mtl12 draws what<br/>D3D12 asks for"]
  C -- "Metal" --> G["fallback attribute:<br/>UChar2 at offset 0"]
  G --> H["integer UVs:<br/>one texel, flat cubes"]
  H --> I["the reference differs<br/>from the D3D12 image"]