The plumbing for O(1) subtree movement (LAYOUT.md §2), with every slot
still at zero, so this changes no pixels and the next commit can change
behaviour against a known-good picture.
Every active widget owns a slot in `UiData::moves`: a translation in
physical pixels and the slot it is relative to. A primitive instance and
a mask each name one, and `prelude.wgsl` walks the chain and adds the
accumulated delta. A mask resolves its own chain rather than the drawn
primitive's, so a stationary viewport can clip content that moves inside
it. `CHAIN_LIMIT` is stated on both sides; it bounds a malformed cycle
rather than any real tree.
A slot outlives any one `ActiveData`, because a redraw replaces that
while the widget's children go on pointing at the slot, so it lives in
`UiRenderState::moves` keyed by widget and is retired when the widget
stops being drawn. `MoveIdx` is its own type rather than another
`Id<u32>`: it sits beside `MaskIdx` in an instance and the two must not
be swappable.
`Vec2` is now `repr(align(8))`, which is WGSL's alignment for a
`vec2<f32>`, so a GPU struct holding one is laid out the way its shader
reads it without saying so itself -- `GlyphPrimitive` no longer states
its own alignment, and `MoveOffset` never has to. Both keep a manual
`unsafe impl Pod`, since the trailing padding that alignment introduces
is what `derive(Pod)` refuses. `WindowUniform` holds the `Vec2` its
shader has always called `dim` rather than two loose floats, which was
the last place the two sides described the same bytes differently.
Checked: fmt, clippy and 40 tests. `tabs` (with the image replay),
`view` and `minimal` render byte-identical to `upstream/main`, and
`text` is unchanged.
Two majors, and the renderer is under everything else left to extract -- so it goes before the slices that would otherwise be written against wgpu 28 and then again against 30. `image` 0.25.6 -> 0.25.10 rides along. `winit` stays on 0.30.12, since 0.31 is only a prerelease and nothing here needs it; `parley` 0.11.1 is current.
What the API asked for, beyond the version:
- **An instance takes the display it will present on**, and GLES on Wayland needs it, so the window the surface is made from is handed over with it. That one matters for Android rather than for this machine.
- **`get_current_texture` returns a status rather than a `Result`**, which replaced an `unwrap` that would have panicked on a resize or an occluded window: reconfigure when the surface is outdated, lost or suboptimal, and skip the frame when there is nothing to draw into.
- **Presenting moved to the queue**, still after `pre_present_notify`.
- **Bind group and vertex buffer layouts are sparse**, so each slot states `Some(layout)`.
Verified the same way as #11: the tabs example with two runtime-added images, an image alone in a layer, and glyphs from a four-page atlas all render identically. `tests/draw_cost.rs` gives 33.6/167/587/2855 us per frame at 8/64/256/1024 layers, against 33.3/161/588/2903 on wgpu 28 -- no change.
---------
Co-authored-by: iris <2+iris@noreply.localhost>
Reviewed-on: iris/iris#13
Reviewed-by: iris <2+iris@noreply.localhost>
Co-authored-by: AIris <4+iris-ai@noreply.localhost>
Replaces the bindless `binding_array<texture_2d<f32>>` the renderer bound every texture through. That array needs `VK_EXT_descriptor_indexing`, which a real share of Android GPUs lack, so the old shape did not run there at all.
The two things being bound want opposite treatment, so they are now split:
- **Glyph atlas pages become layers of one `texture_2d_array`.** A glyph primitive carries a `layer` instead of a view/sampler index pair. A layer index is an ordinary sampling operand, so this needs nothing beyond plain Vulkan 1.0 / GLES. Growing the atlas recreates the array with headroom and `copy_texture_to_texture`s the old layers across, no readback.
- **A standalone image gets its own texture and its own bind group,** and draws in its own call. It no longer needs a per-instance entry in `PrimitiveData`: the bind group has already picked the texture.
`Primitives` keeps images in a list of their own as a result, with `PrimitiveChange::is_image` naming which list a renumbering belongs to -- the two have independent index spaces, so `(layer, inst_idx)` alone would collide between them.
Two notes on judgement calls, since this slice was rebuilt on top of `main` rather than transplanted:
- The source version renamed `GlyphEntry::is_colored` to `is_color` and added a second `IS_COLOR` flag constant beside the existing `GlyphEntry::IS_COLORED`. Both dropped: #10's naming and its `flags()` are kept, and UVs stay `Vec2` rather than going back to `[f32; 2]`.
- `ImageGpu` no longer holds the `Texture` behind its view, which removes an `#[allow(dead_code)]`. A `TextureView` keeps its own reference to the texture, checked by rendering rather than assumed -- see below.
### Verification
```
cargo fmt --all --check
cargo clippy --workspace --all-targets --locked -- -D warnings
cargo test --workspace --locked
```
All clean; the 4 text-edit tests pass. The only clippy output is the pre-existing future-incompatibility notice about `naga`/`wgpu`/`winit`.
Because this is a rendering change, it was also run for real rather than only compiled. The `tabs` example was rendered on this machine's GPU -- Venus onto an RX 7900 XT, confirmed from the loaded ICD (`libvulkan_virtio.so` on `/dev/dri/renderD128`) rather than assumed, since a failed Vulkan init here silently falls back to llvmpipe and would make the screenshots meaningless.
Screenshots before and after the change are **byte-identical** (same md5) in two scenes: the default tab, which exercises text (the atlas path) and rects, and the image tab with a standalone image pushed at startup, which exercises the per-image bind group. The image-tab scene needed a temporary local edit to the example to push the image without a click; that edit is not part of this branch. The same comparison, re-run after dropping the `Texture` field, is still byte-identical -- which is the check that the view alone keeps it alive.
---------
Co-authored-by: iris <2+iris@noreply.localhost>
Reviewed-on: iris/iris#11
Reviewed-by: iris <2+iris@noreply.localhost>
Co-authored-by: AIris <4+iris-ai@noreply.localhost>
iris-ai
