a3d 0.9.0

Changelog

All notable changes to a3d are recorded here. The format follows
Keep a Changelog, and versions follow
Semantic Versioning.

[0.9.0] - 2026-09-11

First public release.

0.9 rather than 1.0 because the container format is at v0.1 and is still
allowed to change: a MRPH chunk is reserved but unimplemented, and the
uint16 vertex index is a format-level ceiling that a future version may
raise. Everything documented in the README as verified has been run on
hardware.

Added

• Binary asset container (.a3d): offsets rather than pointers, so an image
  is usable in place from memory-mapped flash with no fixup pass.
• Scene runtime: node hierarchy, world transforms, materials, textures.
• Skeletal animation: clip playback, quantized channels, GPU-free skinning
  parallelised across an executor.
• Tile binner: per-tile triangle lists, so a scene renders into a small
  internal-RAM tile rather than a full framebuffer.
• Software rasterizer (SoftBackend): RGB565, Gouraud and flat shading,
  perspective-correct texturing with mipmaps, nearest and bilinear filtering,
  specular, transparency, depth-aware 3D lines, and a no-depth fast path.
• 2D canvas and bitmap text: a hand-authored 5x7 font, plus generated 8x14,
  12x21 and 20x35 sizes in a header each, and one blitter that reads all of
  them. tools/gen_font.py produces more from any monospace TTF whose licence
  allows it; see docs/FONTS.md.
• Executors: serial, std::thread, and FreeRTOS.
• Loaders: stdio, ESP-IDF partition, SD/SDMMC, and STL (binary and ASCII, from
  a file or from memory, welded and fed through the same binner and rasterizer
  as a container mesh).
• Python exporter: glTF/GLB to .a3d, with mesh decimation and animation
  key reduction.
• Arduino library support, from the same files as the ESP-IDF component.
  Everything lives under one src/ root because Arduino adds exactly
  <lib>/src to the include path and will not add a second; ESP-IDF is told
  INCLUDE_DIRS "src" and every #include "a3d/...", "viewer/...",
  "backends/..." and "loaders/..." resolves from it. #include <a3d.h>
  brings up the renderer in one line - it is at the root of src/ because
  Arduino's resolver indexes only the headers directly there, and a library
  whose every header is one level down is never matched at all.
• Two Arduino sketches under examples/Arduino/, which the IDE shows as one
  submenu. Waveshare_ESP32-S3-Touch-AMOLED-1.75C puts Fox and CesiumMan on a
  466x466 round AMOLED and runs from boot; Model_From_Header renders off
  screen and needs no wiring at all. Both compiled and linked on arduino-esp32
  3.3.10. Neither has been flashed.
• tools/a3d_export.py --header FILE.a3d writes a container as a C byte array,
  which is the only way onto an Arduino board short of a file system. The array
  is 4-byte aligned, and that is required rather than cosmetic: a3d casts the
  base pointer to the file header, so an unaligned container is refused on the
  board and never at compile time.
• a3d::Viewer (src/viewer/a3d_viewer.h): a model on a screen in four calls -
  begin(), an open*(), frame(). It owns the tile buffers, the binners,
  the orbit camera and the animation player, and it exists to make the orderings
  that are silent when wrong impossible to get wrong.
• a3d_view: renders a container to a PNG contact sheet on the host, so an
  asset can be looked at before it is ever flashed.
• a3d_export.py --project DIR writes a buildable ESP-IDF project around a
  model, and --panel / --touch generate the display glue for the buses this
  project has driven glass with.
• Board detection for ESP32-P4, ESP32-S3 and ESP32-C6, including whether the
  part has a floating-point unit.

Known limitations

See the README. The short version: textures must be power-of-two RGB565, a
single mesh cannot exceed 65,535 vertices, there is no top-left fill rule, and
a part without an FPU (ESP32-C6) is roughly an order of magnitude slower.