A 20-second camera orbit around a glossy race car in a neon workshop. The supplied OBJ and MTL are parsed by Jet at startup: this is a model-loading example, not a generated C++ mesh. The car contains 404 triangles, including four triangles for its separately authored front and rear windows.

• Textured Phong body paint with a coloured ambient light, directional light and additive specular highlights (exponent 32). This creates a metallic appearance; it is not a physically based metal/roughness material.
• All four wheels use the original livery texture unlit, with specular disabled. The body has 200 Phong triangles; the wheels have 200 unlit triangles.
• A shared 256x256, 256-colour livery: 64 KiB of indices plus a 512-byte RGB565 palette. Palette textures use nearest sampling and perspective-correct UVs.
• A 128x64 RGB565 workshop panorama with nearest sampling on the windows. environmentReflectionUV computes view-dependent reflection coordinates from world-space surface positions, normals and camera position. U is unwrapped across the panorama seam before triangle interpolation.
• Opaque chrome-style windows reflect the distant-room panorama. This is an approximation: it does not capture the current framebuffer, reflect the car itself, or reproduce nearby geometry with parallax.
• Unlit workshop geometry, neon strips and a rectangular contact shadow, with painter sorting and no depth allocation. Background geometry is submitted before the sorted body and windows. This arrangement is tailored to the orbit; it is not a general solution for arbitrary intersecting models.

The workshop palette and window panorama have lifted dark tones for the S3 display. Body ambient lighting is RGB (130, 123, 150), preserving the cool/purple tint and existing directional/specular settings.

The floor grid uses 440-unit cells (18 narrow quads, 36 triangles). The shadow is one two-triangle, 360-by-930 rectangle inset from the car's footprint. Both remain untextured, unlit geometry.

The original export shares the body material with its first wheel. Asset preparation rebinds only that wheel to an existing, identical wheel material before embedding the OBJ. Source files, geometry and UVs remain unchanged.

The original export's inward normals and mirrored coordinate system are converted in loadCar: reflect positions across X and negate the Y/Z normal components, retaining the original triangle order and UV islands. The texture conversion also changes the image's vertical origin to match OBJ UVs. Flipping the whole atlas horizontally would put tyre and body regions on the wrong faces.

Jet's loader reuses vertices with identical position/UV/normal indices, retaining UV and hard-normal seams. MTL textures are matched against a supplied texture library; unresolved maps retain the material colour. The loader currently expects positive v/vt/vn face indices and triangles or quads. It is not a full OBJ/MTL implementation or an image decoder.

Both textures use nearest sampling, and BILINEAR_FILTER=0 removes the unused filtering path from this example. To compare filtered windows, enable that build option and set environment.bilinear=true in Workshop::loadCar.

The shared runtime provides the same dual-core rendering, queued scanout and full-resolution FPS/MS/TRIS/TRI-S overlay as the other examples. FPS counts fields; MS and TRI/S use actual render time, including setup and both raster workers.

Jet's opaque untextured UNLIT span path makes the room cheap even in a build with Phong and texturing enabled. Eligible spans use paired/SIMD RGB565 stores while textured, lit, blended and custom-shader materials retain their regular paths. The example places larger static mesh allocations in PSRAM during startup, then restores the normal allocation threshold, leaving internal memory for hot transform scratch. Immutable texture data stays in flash.

Jet also detects exactly matching triangle normals in Phong/Gouraud and evaluates their lighting once per triangle. Phong keeps its additive specular highlight; Gouraud also requires matching cached vertex brightness. This model's 200 Phong body triangles have constant normals, so they are eligible without changing materials; the 200 wheel triangles bypass lighting entirely. Smooth triangles keep their interpolating path. Fixed-point colour rounding can differ slightly from the original per-pixel normal interpolation.

Measured S3 cadence with the simplified floor/shadow, nearest-sampled windows and unlit wheels averages 59.8 fields/s after startup. Earlier versions ran at 45-52 before the constant-normal shortcut and 25-28 before the earlier optimisations. See the validation record for conditions and limits.

From an ESP-IDF 6.0.x terminal in this directory:

idf.py -B build-s3 "-DIDF_TARGET=esp32s3" "-DSDKCONFIG=sdkconfig.s3" build
idf.py -B build-s3 "-DIDF_TARGET=esp32s3" "-DSDKCONFIG=sdkconfig.s3" -p PORT flash monitor

Use the template wiring. P4 configuration is included, but this example has only been built and measured on S3.

For a C++17 host compiler and CMake (use a developer prompt for MSVC):

cmake -S tests -B build-preview -DCMAKE_BUILD_TYPE=Release
cmake --build build-preview --config Release
ctest --test-dir build-preview -C Release --output-on-failure

The tests write car.ppm, showing four orbit views. Preview counters remain unmeasured. Hardware provides the performance measurements.

The source files and prepared textures live in assets; generated headers are checked in, so Python is not required to build the firmware. To regenerate them, install Pillow and run python tools/prepare_assets.py. Optionally pass --font path/to/font.ttf for the two bitmap labels. See asset provenance.