Solo C++20 · Vulkan 1.3 · no editor host

Hybrid renderer I own end to end — path tracer + deferred on one scene graph.

Not a Unity plugin. Not a toy Cornell box. ~52K lines C++, ~14K GLSL, 121 shaders — KHR RT, ReSTIR GI, DLSS Ray Reconstruction, and a multi-pipeline inverse lab with published ΔPSNR plates.

Shaoxuan (Frank) Yin github.com/Qervas/ohao_engine Graphics / GPU systems

~67 fps

RT path-traced helmet orbit
DLSS-RR · outdoor HDRI

+24.5 dB

Diff-IR quality plate ΔPSNR
outdoor dense roughness

2 pipes

Deferred + KHR PT share
scene · materials · TLAS

Watch the story Source Inverse RESULTS Portfolio

Live · path-traced orbit

01 — Architecture

One scene. Two rendering contracts.

Built to learn how a modern hybrid renderer is wired — not wrapped in an engine SDK. Path tracer is ground truth and indirect light. Deferred is interactive iteration. Hybrid adds RT shadows + 1-bounce RT GI on the deferred G-buffer.

Path tracer

Vulkan KHR RT

Raygen / closest-hit / miss / any-hit. MIS with Owen-scrambled Sobol. Offline + realtime rgen variants. NEE, env CDF, progressive accumulation.

Deferred

Real-time product path

G-buffer, bindless materials, PBR (Cook-Torrance GGX). Shared TLAS with the RT stack. Fast iteration without reloading the world.

Systems

Not only pixels

Physics (GJK/EPA + BVH), audio, animation, scene ECS. Same C++20 modular layout — render / gpu / physics / scene crates.

DamagedHelmet · PBR metal / glass / cables

Lantern · emissive + wood structure

MetalRoughSpheres · rough↔smooth · metal↔dielectric calibration grid

02 — Real-time path tracing

Interactive 1-spp that still looks intentional.

NVIDIA DLSS 4 Ray Reconstruction (raw NGX Vulkan on Linux) + vendor-neutral SVGF. ReSTIR GI on outdoor HDRI. Offline path: Intel OIDN + NRD compose.

ReSTIR GI · outdoor

ReSTIR off ReSTIR on Drag

OIDN · 16 spp helmet

16 spp raw OIDN Drag

DLSS-RRNGX Vulkan · Linux

SVGFvendor-neutral denoise

ReSTIRGI reservoirs · outdoor

OIDN / NRDoffline + compose

03 — Inverse lab

Recover materials from pixels — on the same Vulkan host.

Multi-pipeline IR: path-tracer oracle (capture-gated LABTEST) + Diff-IR Deferred sibling where free dense maps are the beauty source of truth. Fit is train-only. Published dB always name the metric domain.

Diff-IR quality plate · 1080p SHOW · spheres · helmet · outdoor — wrong init → recovered → GT

Preset	Init → train PSNR	ΔPSNR	Rough map MSE	Domain
spheres	38.3 → 58.1	+19.8 dB	0.362 → 0.179	Deferred dense ORM · 1080p
helmet	35.8 → 57.6	+21.8 dB	0.362 → 0.081	same
outdoor	32.4 → 56.9	+24.5 dB	0.362 → 0.194	same

Novel-HDRI relight + recovered roughness maps

PT capture-gated oracle · lantern frontier · holdout 32.5 dB

Dense metallic ORM.b · ΔPSNR +26.8 dB · map MSE 0.405 → 0.006

Museum amphora · MAPTEST +21.5 dB · domain ohao_museum_studio_protocol

Analytic albedo path: GRADCHECK vs finite differences, ~19.7× wall-clock vs full 3-pass coord FD. Not reverse-mode autodiff theater — linear solve + residual + sparse polish

04 — Interview mode

They ask X. You point here.

Keyboard 1–5 jumps beats. Send this URL before the call. No textbook chapters — proof first.

They ask	You show
“What is OHAO?”	Hero — hybrid Vulkan RT, orbit video, ~67 fps claim
“Path tracer or raster?”	Stack — both, shared scene / materials / TLAS
“How do you make 1-spp usable?”	Realtime — drag ReSTIR + OIDN compares
“Any research-y results?”	Inverse — Diff-IR plates, +19.8…+24.5 dB, capture-gated PT
“Is inverse just a slide demo?”	No — live `inverse_fit` + RESULTS.md tables; museum / dense maps ship in docs/media
“Code?”	github.com/Qervas/ohao_engine

OHAO Engine — solo Vulkan 1.3 hybrid renderer (path tracer + deferred + inverse lab). Demo: https://qervas.github.io/ohao-engine/

GitHub Inverse RESULTS Portfolio Thesis demo Email Frank