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>
Iris asked whether the 'unknown number of images' approach even works on
mobile. It does not, measured with a new rig (rigs/gpu-probe, no APK
needed) and sourced rather than recalled: the emulator's software Vulkan
refuses iris's descriptor-indexing request outright, and on real hardware
the current Android Vulkan Profile baseline (80.1% of active devices)
does not require VK_EXT_descriptor_indexing either -- Arm's own docs say
only Valhall/5th-Gen Mali (2019+) support it.
iris already solved the identical problem for text in I1 (the glyph
atlas). The recommendation is to generalize it to images rather than
widen the binding array further; not yet implemented, since it changes
iris's render core.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
irisandClaude Sonnet