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.

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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 →

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The Trailer

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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.

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
• Froxel volumetric fog, a single view-aligned volume for height and distance fog, sun shafts, and underwater caustic shafts, with temporal reprojection and shadowing
• 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 3 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)

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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.

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Engine Systems

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Getting Started

Building

One-click project generation—see the Building Guide for details.

Learning the Engine

Start with Engine.cpp, it is the engine entry and the best place to learn the startup path. For gameplay scripting, check out the Lua Scripting Guide, it covers the full API, lifecycle callbacks, and examples.

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Podcast

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Community

Contributing

Contributors get access to exclusive perks designed to accelerate learning and skill development.

Read the Contributing Guide →

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 goes directly into keeping the lights on and the project moving.

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Projects Using Spartan

Using code from Spartan? Reach out, I'd love to showcase your project!

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License

MIT License, free to use with attribution.