One engineer. Twelve years. A bindless, GPU-driven engine with real-time path-traced global illumination.

A personal R&D engine, not a commercial product. No roadmap promises, no support queue, no compromises on the vision.

--- ## The Engine Spartan started as a university project. Ten years of nights and weekends later, its rendering technology runs in **Godot Engine** and **S.T.A.L.K.E.R. Anomaly**, ships in a **published programming book**, and anchors a community of **600+** engineers on Discord. This is what a codebase looks like when a single person owns every line for a decade: no legacy committees, no half-migrated architectures, no "we'll fix it in the next version." One philosophy applied without compromise: **favor real-time over baked, dynamic over static, modern over safe.** Every system here exists to serve that. **There is a destination that gives all this tech a purpose.** Curious? **[Read the plan →](https://github.com/PanosK92/SpartanEngine/blob/master/plan.md)** --- ## The Trailer [![Engine Trailer](https://raw.githubusercontent.com/PanosK92/SpartanEngine/master/.github/images/video_promo.png)](https://www.youtube.com/watch?v=TMZ0epSVwCk) --- ## Worlds

Launch the engine and choose from a selection of default worlds. Nothing is a canned demo—every world is physics-enabled. Walk around, pick up objects with your mouse, or take a car for a spin.
### Forest

The most demanding world: **256 million** procedurally generated grass blades (inspired by Ghost of Tsushima), spanning **64.1 km²** covered with thousands of trees and rocks. ### More Worlds | Sponza 4K | Basic | |:-:|:-:| |

Classic Dubrovnik building—ideal for path tracing |

Reality shifts to a nearby frequency |

A neon-soaked city, built to push the engine toward real-time path-traced driving through rain-slicked streets at 60fps, that's the plan. | --- ## Rendering The renderer is built around one principle: **the GPU owns the data.** Every resource (geometry, materials, textures, lights, transforms, AABBs) lives in persistent, globally accessible buffers. No per-draw descriptor updates, no per-draw resource binding, no CPU-side draw loops. ### Architecture - **Zero-binding draw path**, all per-draw data lives in a single bindless storage buffer, push constants carry only an index - **Single global vertex and index buffer** for all geometry (inspired by id Tech), with **vertex pulling** that bypasses the Input Assembler and is shared by rasterization and ray tracing - **GPU-driven indirect rendering** with per-meshlet frustum, Hi-Z occlusion, and backface cone culling, the CPU issues a single `DrawIndexedIndirectCount` per pass - **Meshlet clustering** via meshoptimizer, no mesh shader dependency - **Bindless everything**: materials, lights, samplers, uber shaders, minimal PSO permutations - **Universal HLSL** compiled for both Vulkan (SPIR-V) and DirectX 12 - **GPU-side asset processing**: mip generation (FidelityFX SPD) and texture compression (Compressonator) at load time, not baked offline - **Unified deferred rendering**, opaque and transparent surfaces share the same BSDF and render path - **Async compute** for SSAO and screen-space shadows, parallel with shadow rasterization ### Lighting and Global Illumination - **ReSTIR path tracing** with spatiotemporal reservoir resampling for real-time multi-bounce global illumination - **Clustered deferred shading** with a GPU-built logarithmic-Z grid and cone-vs-AABB culling for spots, scales to many local lights at near-constant per-pixel cost - **Hardware ray-traced reflections and shadows** via ray queries - **Atmospheric scattering** and image-based lighting with bent normals - **Volumetric clouds** (Nubis-style) baked into the sky panorama, with cumulus and cirrus layers, multi-scatter lighting and aerial perspective - **Volumetric fog** with temporal reprojection and shadow casting - **FFT ocean** with a Tessendorf spectrum and multi-cascade IFFT in compute, driving a camera-following clipmap with choppy displacement, dynamic normals and crest foam - **Screen-space shadows** (inspired by Days Gone) and **XeGTAO** ambient occlusion - **Shadow map atlas** with fast filtering and penumbra estimation ### Performance and Upscaling - **Variable rate shading** and **dynamic resolution scaling** - **TAAU**, temporal anti-aliasing with built-in upsampling, Halton-jittered with variance-clip history reprojection - **Intel XeSS 2** upscaling - **FXAA** - **Custom breadcrumbs** for GPU crash tracing and post-mortem debugging ### Camera and Post-Processing - Physically based camera with auto-exposure and physical light units (lumens and kelvin) - Tonemappers: ACES, AgX, Gran Turismo 7 (default) - HDR10 output - Bloom, motion blur, depth of field, chromatic aberration, film grain, sharpening (CAS) --- ## Car Simulation — 200Hz A full vehicle dynamics simulation running inside the PhysX fixed-timestep loop. Not a gameplay approximation—the kind of model you'd expect from a dedicated racing sim, embedded in a general-purpose engine. | System | Details | | ------------------- | -------------------------------------------------------------------------------------------------- | | **Tires** | Pacejka MF 5.2 with combined slip, thermal model, pressure, wear, multiple surfaces | | **Suspension** | Convex hull sweep contact, spring-damper, anti-roll bars, bump stops, bump steer, camber/toe | | **Weight transfer** | Geometric + elastic lateral split via roll center heights and roll stiffness | | **Drivetrain** | Engine torque curve, turbo, 7-speed gearbox, rev-match, open/locked/LSD differentials, RWD/FWD/AWD | | **Brakes** | Thermal model with fade, front/rear bias, slip-threshold ABS | | **Aerodynamics** | Drag, front/rear downforce, ground effect, DRS, rolling resistance | | **Steering** | Ackermann geometry, high-speed reduction, self-aligning torque | | **Assists** | ABS, traction control, handbrake | | **Integration** | Semi-implicit Euler with consolidated net-torque per wheel | | **Input** | Controllers and steering wheels with haptic feedback | | **Camera** | GT7-inspired chase camera with speed-based dynamics | --- ## Engine Systems | System | Details | | ----------------- | ------------------------------------------------------------------------------------------------- | | **Particles** | GPU-driven with compute emission and simulation, depth-buffer collision, soft blending | | **Animation** | Full skeletal animation: keyframed clips, crossfade blending, four-bone skinning, and two-bone inverse kinematics with ground-aware foot planting | | **Physics** | PhysX with rigid bodies, character kinematics, and vehicle dynamics | | **Scripting** | Lua 5.4 via Sol2 with full engine API and lifecycle callbacks | | **Audio** | 3D positional audio, streaming, reverb, procedural synthesis via SDL3 | | **Input** | Keyboard, mouse, controllers, and steering wheels with haptic feedback | | **Entity system** | Component-based with transform hierarchies, prefabs, and XML serialization | | **Procedural roads** | Catmull-Rom spline roads with extruded profiles, terrain conforming, instanced prop placement, and path followers | | **Cinematics** | Camera cut sequencer with entity tracking, spline-driven movement, and exact cut timing | | **Threading** | Hardware-aware thread pool with parallel loops and nested parallelism detection | | **VR (WIP)** | OpenXR with multiview single-pass stereo (Vulkan and DirectX 12) | | **Profiling** | Nsight/RGP-style timeline with separate graphics and async compute lanes, RenderDoc integration | | **Asset import** | 40+ model formats (Assimp), 30+ image formats (FreeImage), 10+ font formats (FreeType) | | **Editor** | ImGui-based with hierarchy, asset browser, inspector, script and shader editors, gizmos, profiler | --- ## Getting Started ### Building One-click project generation—see the **[Building Guide](https://github.com/PanosK92/SpartanEngine/wiki/Building)** for details. ### Learning the Engine Start with **[Game.cpp](https://github.com/PanosK92/SpartanEngine/blob/master/source/runtime/Game/Game.cpp)**, it shows how default worlds are loaded and is the best entry point for understanding the engine's structure. For gameplay scripting, check out the **[Lua Scripting Guide](https://github.com/PanosK92/SpartanEngine/wiki/Scripting)**, it covers the full API, lifecycle callbacks, and examples. --- ## Podcast

Exploring the tech world and beyond

Meeting the brightest minds across cutting-edge industries.

📺 Watch on YouTube
🎧 Listen on Spotify

--- ## Community ### Contributing Contributors get access to **[exclusive perks](https://github.com/PanosK92/SpartanEngine/wiki/Perks-of-a-contributor)** designed to accelerate learning and skill development. **[Read the Contributing Guide →](https://github.com/PanosK92/SpartanEngine/wiki/Contributing)** ### Sponsorship I cover the Dropbox hosting that makes the one-click setup work. If Spartan has taught you something, or if you just want to fuel another decade of this, **[sponsorship](https://github.com/sponsors/PanosK92)** goes directly into keeping the lights on and the project moving. --- ## Projects Using Spartan | Project | Description | | -------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Godot Engine** | Integrates Spartan's TAA ([view source](https://github.com/godotengine/godot/blob/37d51d2cb7f6e47bef8329887e9e1740a914dc4e/servers/rendering/renderer_rd/shaders/effects/taa_resolve.glsl#L2)) | | **S.T.A.L.K.E.R. Anomaly** | Rendering addon using Spartan's source ([ModDB](https://www.moddb.com/mods/stalker-anomaly/addons/screen-space-shaders)) | | **Programming Book** | Jesse Guerrero's [beginner programming book](https://www.amazon.com/dp/B0CXG1CMNK) features Spartan's code and community | | **University Thesis** | Originally created as a portfolio piece while studying at the [University of Thessaly](https://en.wikipedia.org/wiki/University_of_Thessaly) with Professor [Fotis Kokkoras](https://ds.uth.gr/en/staff-en/faculty-en/kokkoras/) | **Using code from Spartan?** [Reach out](https://twitter.com/panoskarabelas), I'd love to showcase your project! --- ## License **[MIT License](https://github.com/PanosK92/SpartanEngine/blob/master/license.md)**, free to use with attribution.