Reasoned through but never watched happen, per the file's own "Not
separately stress-tested" note. Temporarily dropped PAGE from 1024 to
64 so tabs's ordinary mix of text sizes/families already exceeds one
page; a throwaway eprintln in grow_array confirmed two real grows in
one run (1->2, 2->4 layers), and run-headless.sh showed every tab's
text rendering correctly across layers, with no corruption. Both
temporary changes reverted; tabs and minimal confirmed byte-identical
to the pre-check screenshots afterward.
Co-Authored-By: Claude Sonnet <noreply@anthropic.com>
The old pipeline bound every texture ever drawn (glyph atlas pages and
standalone images alike) in one binding_array<texture_2d<f32>> and asked
every device, unconditionally, for VK_EXT_descriptor_indexing -- which a
real share of Android GPUs lack and which failed outright on the Android
emulator's software Vulkan (see TEXTURES.md's "iris's binding array does
not survive real Android hardware").
Implements TEXTURES.md's "Recommended shape": the glyph atlas is now one
texture_2d_array (a layer per page, grown by doubling + GPU-side
copy_texture_to_texture); a standalone image is its own ordinary Texture
and BindGroup, drawn with its own draw() call from a separate per-layer
instance list; group 2's layout is {atlas array, one image slot, sampler,
masks}. request_device now asks for no features and no binding-array
limits at all, and UiLimits is gone.
Also fixes (by making moot) the changed=false bug the review found, where
a Patch in the same batch could cancel an earlier Push's rebuild signal,
and documents the swap_remove draw-order invariant apply_free already
relied on.
Verified: cargo fmt/build/clippy/test clean in iris/ on the pinned
nightly; minimal and tabs render correctly via run-headless.sh; a
throwaway example confirmed the standalone-image bind-group path renders;
rigs/gpu-probe, updated to the new empty feature/limit set, confirms
request_device succeeds on the ai-app-2 emulator's software Vulkan
(EMU_GPU=software) -- see TEXTURES.md's "Implemented, 2026-09-04" for the
exact command and output. RUST.md's blocking item is resolved.
Co-Authored-By: Claude Sonnet <noreply@anthropic.com>
Written for review before iris's render core changes. Covers the bindless
binding-array problem, the gpu-probe measurements (emulator and sourced
real-hardware findings), what growth already costs today in the current
code, the egui_wgpu/Vello prior art, and the recommendation with its open
questions -- not yet implemented.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
irisandClaude Sonnet