Three ways to disappear.
glTF does not ask the renderer to guess what alpha means. The asset declares OPAQUE,
MASK, or BLEND; GLTFLoader maps that contract into material sorting,
alpha testing, depth writing, and face policy.
Building one loader-parsed glTF asset with three declared alpha modes…
- backend
- —
- modes
- —
- meshes
- —
- draw calls
- —
- frame ms
- —
The parsed materials will expose their alpha policy after GLTFLoader finishes.
waiting
waiting
waiting
- OPAQUE
- —
- MASK
- —
- BLEND
- —
The opaque subject behind the panels makes MASK's discarded fragments and BLEND's sorted overlay visible.
WebGPU and WebGL2 use the same generated glTF fixture; the renderer backend changes the material implementation, not the declared alpha modes.
The renderer or GLTFLoader could not create the study.
Derived from the official GLTFLoader and Material contracts, the official WebGPU alpha-hash, WebGL alpha-hash, and physical transmission alpha examples, and the Khronos glTF alpha coverage contract. Use ?forceWebGL=1 to inspect the forced WebGL2 path.