Makes large-model streaming over a network actually good — fixing read
amplification, then first-paint latency — building on the byte-range work.
v14 layout + TOC (SidecarLayout, pure + unit-tested)
The loader chunks meshes by spatial Morton order, but the sidecar stored
geometry in mesh-id order, so a chunk's meshes were scattered through the
file: streaming one chunk meant either hundreds of tiny range requests or
reading (and discarding) everything between them — a 113 MB model fetched
~340 MB, a 531 MB model 2.25 GB (4.2x). Fix: at bake, reorder meshes into
the loader's chunk order and rebuild vertex/index(LOD0+LOD1)/instance
sections so each chunk is one CONTIGUOUS byte range, and bake a chunk TOC
({first_mesh, mesh_count}). The loader builds chunks straight from the TOC
rather than re-deriving the plan — the float Morton quantisation isn't
bit-identical across toolchains (x86 baker vs wasm loader), so a re-derived
plan scatters the chunks. Format bumped to v14 (regenerate sidecars). The
reorder buckets instances by per-instance mesh_id (the baker never sets
MeshInfo.first_instance — trusting it scrambled every transform → geometry
at the origin). Multiset-verified on a 28,900-instance model: every
instance's placement + geometry preserved. Result: 531 MB fetches 531 MB
(1.0x) in 72 requests (was 2036).
Progressive streaming (concurrency cap + small chunks)
Even at 1x, geometry appeared only after ~the whole model arrived: the
browser multiplexes every in-flight Range request over one HTTP/2 conn, so
unbounded concurrency (9 in flight) split the bandwidth and nothing finished
until the end (measured: first paint after 113 of 118 MB / 35 s @ 24 Mbps).
Cap concurrent chunk loads (kMaxWebInflightChunks=2): the priority-sorted
top chunks finish and paint first, then the next → first paint 9 s. Chunk
size dropped 16->4 MB (cheap now that each chunk is one read; matches Cesium
3D Tiles / xeokit / SVF2) for smoother progression. First-paint is now
metadata-bound (~10 MB tail) — the next lever.
111/111 unit (new test_sidecar_layout: geometry preserved, contiguous layout,
Morton-identity) + 6/6 web smoke pass; desktop bake (SceneLoader) reorders
before writeSidecar; embedded web sample regenerated to v14.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Splits the v13 metadata wire-format knowledge out of the FILE*-bound
streaming reader into pure, buffer-based functions so the web byte-range
path (#88) can reuse it without loading the whole sidecar into the wasm
heap:
- parseSidecarHead — validates the 16-byte head, yields num_vertex_bytes
- parseSidecarTail — parses meshes/instances/georef/elements/strings
from an in-memory tail buffer, bounds-checked
- planSidecarReadRanges + SidecarReadPlan — the range-coalescing /
scatter planner, promoted out of the anonymous namespace
readSidecarMetadataOnly and the range readers now call these; desktop
behaviour is unchanged (head + tail are small, the bulk is still skipped
via seek). The metadata tail is split from the head around the bulk
sections, so a blob-backed loader just slices those two regions and
hands the bytes to the same parsers.
Closes a coverage gap: StreamingLoader had no unit tests. Adds
test_streaming_loader.cpp (7 cases: metadata round-trip, corrupt/truncated
rejection, vertex+index range scatter, head validation, tail truncation,
read-plan coalescing). 107/107 unit tests pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The GL backend is gone (task #53). The wgpu/non-wgpu folder split and
the Wgpu* class prefix were both disambiguation artefacts from the
overlap period — now pure dead weight.
## Folder + library merge
* `src/ifcviewer-wgpu/` → folded into `src/ifcviewer/` (git mv tracks
every file as a rename so blame/log history survives).
* `src/ifcviewer-wgpu-minimal/` → `src/ifcviewer-minimal/` (the exe was
already named `IfcViewerMinimal`; this just brings the folder + CMake
target name into line).
* `src/ifcviewer-wgpu/tests/test_wgpu_{selection,visibility}.cpp` →
`src/ifcviewer/tests/test_{selection,visibility}.cpp`, folded into
the existing `add_ifcviewer_unit_test(...)` helper.
* The `IfcViewerWgpu` static library is dissolved — its sources become
part of the unified `IfcViewer` static library, which now bundles
scene/loader + renderer in one target. The pre-merge circular
dependency (IfcViewer linking IfcViewerWgpu just to get the
ViewportWindow.h include path that SceneLoader.h needs) goes away.
* The wgpu-native FetchContent block, the Cocoa/QuartzCore link on
Apple, the OBJCXX-enabled `.mm` source, and the wgpu-native runtime
install all move into `src/ifcviewer/CMakeLists.txt` unchanged.
## Type renames (Wgpu prefix dropped from every Wgpu* identifier)
WgpuAreaMeasurement → AreaMeasurement
WgpuBufferPool → BufferPool
WgpuLengthMeasurement → LengthMeasurement
WgpuMetalSurface → MetalSurface
WgpuModelGpuData → ModelGpuData
WgpuOverlayFrame → OverlayFrame
WgpuOverlayRenderer → OverlayRenderer
WgpuSectionPlane → SectionPlane
WgpuSelectionState → SelectionState
WgpuStreamingLoader → StreamingLoader
WgpuStreamingThread → StreamingThread
WgpuViewportWindow → ViewportWindow
WgpuVisibilityState → VisibilityState
CMake target IfcViewerWgpuMinimal → IfcViewerMinimal (exe name was
already this since wgpu shipped as default).
Deliberately kept: `onWgpuLog` (wgpu-native log callback — names a
binding to an external API, not one of *our* types), and the WGPU*
enum/struct prefixes from wgpu-native's own headers. `WgpuMemProbe`
lives in the separate `src/wgpu-mem-probe/` standalone diagnostic
project and isn't touched.
## Include-path updates
Every `#include "../ifcviewer-wgpu/Wgpu<X>.h"` → `"../ifcviewer/<X>.h"`,
every in-directory `#include "Wgpu<X>.h"` → `"<X>.h"`. Includes from
sibling subdirectories (modules/, etc.) are updated to point at
`../../../ifcviewer/` instead of `../../../ifcviewer-wgpu/`.
## cmake/CMakeLists.txt simplification
The redundant `add_subdirectory(ifcviewer-wgpu)` blocks (one inside
the BUILD_BONSAIVIEWER fan-in, one in the BONSAIVIEWER-less standalone
block) collapse into a single unconditional
`add_subdirectory(../src/ifcviewer ifcviewer)`. The standalone block
keeps only `wgpu-mem-probe` (the diagnostic tool, unrelated to the
viewer lib).
## Verification
* Full build green: `IfcViewer` static lib, `IfcViewerMinimal` exe,
`BonsaiViewer` exe, all four pre-existing ifcviewer unit tests, and
the two new-location tests (`test_selection`, `test_visibility`).
* No stray `Wgpu<X>` identifier remains across `src/ifcviewer/`,
`src/bonsaiviewer/`, `src/ifcviewer-minimal/` (verified by grep).
* Renames tracked by git as `R` entries — `git log --follow` on
ViewportWindow.cpp etc. continues to show history through the move.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Dion Moult