2026-06-17

[markaren]

Changelog

A large feature release: procedural content generators (terrain, trees, grass,
roads), big Vulkan path-tracer and WebGPU advances, cross-backend shadow
improvements, several new demos (forest, drive, mountains, RL swarm, LIDAR-SLAM),
and a reinforcement-learning (RLtools) integration.

Added — library

• Procedural vegetation — extras/vegetation/TreeGenerator + TreeTextures
  (parametric trees with bark/leaf textures, color variation and clumping) and
  GrassField (reusable instanced GPU vertex-shader wind grass for GL/WebGPU).
• GrassMesh — a Vulkan-oriented grass object: a single merged geometry
  GPU-deformed by a wind compute pass with in-place BLAS refit (one TLAS
  instance for an entire field).
• Procedural terrain — extras/terrain/TerrainGenerator: noise + hydraulic
  (droplet) and thermal erosion, slope/altitude/snow splat → albedo, with
  import/export.
• extras/road/RoadGenerator — centerline/corridor road generation.
• Point-cloud / mapping utils — extras/pointcloud/{Icp, VoxelGrid, MarchingCubes} (used by the LIDAR-SLAM demo).
• extras/physx/PhysxVehicleEngineDrive — PhysX engine-drive vehicle with
  tire-slip / suspension telemetry.
• utils/Parallel — cross-platform parallel-for with a serial fallback.

Added — examples & demos

• forest_demo — procedural forest: terrain, instanced trees, GPU-wind grass
  and flowers, rocks; runs on GL, WebGPU and the Vulkan path tracer.
• Drive — procedural driving demo (road + terrain + foliage, PhysX vehicle,
  procedural audio, day/night). (Add procedural drive demo #365)
• mountains — procedural mountains, themed presets.
• tree_demo — standalone tree generator showcase.
• RLtools — reinforcement-learning integration: live SAC pendulum trainert
  (pendulum/acrobot); opt-in THREEPP_WITH_RLTOOLS, THREEPP_RLTOOLS_FAST.
• lidar_slam — LIDAR SLAM with occupancy + marching-cubes map views.
• Vulkan capture harness — committed examples/vulkan/capture_util.hpp
  (--cam/--look reframing, --profile per-pass timings, image-diff/PSNR) and
  a gitignored scratch/ convention for throwaway debug tools.

Vulkan (path tracer)

• Performance: a pipeline cache (Vulkan: disk-backed pipeline cache to fix slow startup #366); foliage deform + TLAS refit folded
  into the frame command buffer, removing the per-frame vkQueueWaitIdle
  (CPU scene-prep ~20–40 ms → <1 ms, flat across resolution); light-change fast
  path; ReSTIR DI/GI spatial-reuse skipped on converged static pixels.
• Lighting: GI bounce and reflected-hit (cheapHit) NEE now loop all analytic
  lights for ≤8-light scenes (was 1 stochastic pick → spotlight/point shimmer);
  improved rect-area lights.
• Deferred: glass no longer dull (PT-parity roughness cap, sharper env
  misses, Fresnel glint); secondary rays honor alphaMode (blend composite,
  cutout alpha-test, glass interior stops at embedded content); transmission +
  alphaMode BLEND honored (smoked glass no longer opaque-black); depth-gated
  reflection reproject (fixes edge smear when turning).
• Sprites/particles: render world-space Sprites and ParticleSystem
  billboards. (Vulkan: render world-space Sprites and ParticleSystem billboards #368)
• vulkan_ocean: procedural lighthouse, realistic 3-DOF ship dynamics
  (surge/sway/yaw, rudder/telegraph, autopilot, heel/squat/grounding); GPU grass;
  dead per-vertex foam buffer removed.
• Robustness: fixed startup crash when non-PT objects precede meshes
  (entry-indexed buffers sized to entry count); fixed large-scene flicker and
  runtime-object flakiness; version-aware texture cache; debug-view fixes;
  split-screen (scissor-clipped PT pane + overlay compose).
• Tests: golden-image regression net for the PT/deferred path.

WebGPU

• Instanced ShaderMaterials — the custom (GLSL→WGSL) pipeline now supports
  instanceMatrix (binding-28 storage buffer), so InstancedMesh + a
  ShaderMaterial renders (e.g. the forest's GPU-wind grass).
• Fixed vec2 custom-uniform packing (std140 padding + CPU packer) — any
  ShaderMaterial with a vec2 uniform previously uploaded it as zero.

Shadows (GL + WebGPU)

• WebGPU now renders InstancedMesh shadow casters (a GPU-instanced depth
  pipeline) — instanced trees/rocks previously cast no shadow.
• WebGPU auto-sizes its shadow atlas to the largest per-light shadow->mapSize
  (clamped), instead of a fixed 1024.
• Default shadow-map resolution raised 1024 → 2048 (more expensive shadows by
  default — modern desktop affords it).
• Crane3R: fixed an inverted orthographic shadow frustum.

OpenGL

• Fixed the Reflector rendering reflections too dark (missing output OETF in
  the shared shader; no-op on WebGPU's sRGB swapchain).

PhysX

• physx_vehicle: procedural audio (skid/wind/impacts/horn) from PhysX telemetry;
  brake/reverse lights, RPM + slip HUD; better tire handling and substep tuning.

Fixed

• Sound asset paths (certain example sounds were silently ignored);

Infrastructure / docs

• Compile-only Vulkan CI job.
• README: AI-assisted-development section; research/education framing.

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This discussion was created from the release 2026-06-17.