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origin: floating_fp64_ bodies: n-body gpu epoch: J2000.0
vulkan 1.3 compute: tiled smem integrator: verlet
Proceduralabs / Game Dev / Ikarus
Real-Time Physically Accurate Universe Simulator

Ikarus

A Vulkan-powered, GPU-accelerated space engine that simulates the physics of our universe. Real N-body astrophysics running at interactive framerates.

2M Bodies @ 60 FPS
1M× Time Acceleration
FP64 Floating Origin
RTX 40 Target Hardware
C++20
Language
Vulkan
Graphics API
GLSL 460
Shader Language
GLM
Math Library
VMA
Allocator
CMake
Build System
Watch two neutron stars spiral into a black hole in real time. Feel gravitational waves ripple across the screen as they merge. Crank time to 1,000,000× and watch an entire galaxy evolve in seconds.

Ikarus is not a game engine with physics bolted on. It is a real astrophysics simulator that runs at interactive framerates. Every body in the simulation follows N-body gravitational dynamics computed on the GPU via tiled shared-memory compute shaders.

Fly from Earth to the edge of the observable universe without a single precision error. Real SI units — meters, kilograms, meters per second — everywhere. No arbitrary scaling. No shortcuts. Just physics.

From gravity
to merger

Four-stage GPU simulation pipeline. N-body gravitational dynamics, extended-body collision detection, neutron-star merging with mass-energy conversion, and gravitational-wave emission — all running in parallel on compute shaders.

01

N-Body Solver

Full GPU-accelerated N-body computation using tiled shared-memory compute shaders. Millions of gravitationally interacting bodies at 60+ FPS on RTX 40-series hardware.

Tiled SMEM Compute SSBO
02

Collision & Merging

Extended-body simulation with real radii. Accurate collision detection triggers automatic merging — neutron-star pairs collapse into black holes with momentum conservation and 1–5% mass-to-energy conversion.

Real Radii Merge Queue Schwarzschild
03

Gravitational Waves

Every merger emits a detectable gravitational-wave event. Real-time propagation with screen-space distortion — visible shockwaves rendered as quadrupole stretch/squeeze in the fragment shader.

GW Events Wavefront Quadrupole
04

Time Engine

Variable world-time acceleration from 1× to 1,000,000×+ with adaptive sub-stepping. Fixed-timestep Verlet integrator maintains physics stability at any time scale. Future RK4 upgrade planned.

Verlet Sub-Step RK4 Future
Technical Deep Dive

Core Systems

Coordinate System
01

Double-Precision Floating Origin

The same technique used in professional astrophysics codes. Double-precision coordinates on the CPU, camera-relative 32-bit rendering on the GPU. Seamless travel from planetary surfaces to intergalactic distances with zero jitter.

FP64 CPU Coords
FP32 GPU Render
SI Units Meters / KG
Rendering Engine
02

Instanced GPU Rendering

Real-radius spheres rendered direct from the physics SSBO via instancing. Type-based visuals distinguish rocky planets, glowing neutron stars, and black holes with accretion-disk placeholders. Additive-blend particles with velocity trails.

Instanced Draw Mode
48 Bytes Per Particle
LOD Sphere→Billboard
Procedural Universe
03

GPU Universe Seeding

Compute-shader-driven procedural generation. Spiral galaxies with embedded solar systems, random neutron-star and black-hole populations, and pre-scheduled merger events. One click generates an entire universe.

Compute Seeding
Spiral Galaxy Gen
SPICE Planned Import
Controls & UI
04

ImGui Debug Panel

High-precision quaternion free-fly camera up to 0.999c. Full ImGui panel with world-time slider, spawn menu for planets/NS/BH, gravitational constant tweaking, demo selector, and real-time performance graphs.

Quat Camera
0.999c Max Velocity
ImGui Interface

RTX 4090 Predicted

2M bodies
Newtonian @ 60 FPS

Up to 2,000,000 gravitationally interacting bodies at sustained 60 FPS using tiled shared-memory compute. Scales linearly with GPU compute power.

50K bodies
Full Merging + GW Events

10,000–50,000 bodies with complete collision detection, automatic merging, gravitational-wave emission, and screen-space distortion effects.

~200 MB
Memory for 1M Bodies

48-byte compact GpuParticle SSBO layout. SOA structure on CPU with double precision, minimal memory footprint on the GPU side.

System Design

Architecture & Scale

01

Post-Newtonian Corrections

0.5PN corrections already stubbed into the integrator. Future full 1PN/2PN implementation for relativistic orbits near compact objects — accurate precession and orbital decay without full GR overhead.

0.5PN Stub 1PN / 2PN Precession Orbital Decay
02

Modular Subsystems

Every major system is a self-contained module: floating_origin.h, world_time.h, merge_queue.h, gw_events.h. Open architecture makes it trivial to plug in custom shaders, models, or external data sources.

floating_origin.h world_time.h merge_queue.h gw_events.h
03

Shader Hot-Reload

GLSL 460 compute and fragment shaders support hot-reload during development. Iterate on gravitational-wave distortion effects, accretion-disk visuals, and particle rendering without restarting the engine.

GLSL 460 Hot Reload Compute + Frag Live Iteration

Under the Hood

Language C++20
Graphics API Vulkan 1.3 (Hpp)
Base Sascha Willems computenbody fork
Math GLM (double-precision)
Allocator VMA
Build CMake + Ninja
Shaders GLSL 460 (hot-reload)
GPU Storage 48-byte GpuParticle SSBO
CPU Storage SOA, double precision
Platform Cross-platform (CMake)

Implementation Roadmap

Phase 1 Complete

GPU N-Body Foundation

GPU N-body base with double-precision stubs, compute shader pipeline, and injection points for all future subsystems. The scaffolding everything builds on.

N-Body Base FP64 Stubs Compute Pipeline
Phase 2 In Progress

Floating Origin & Live Mergers

Floating origin coordinate system, world-time acceleration, live neutron-star/black-hole merging with visible gravitational-wave time ripples. Nine fully working one-click demos.

Floating Origin World Time NS/BH Merging GW Ripples 9 Demos
Phase 3 2–4 Weeks

Procedural Galaxy & LOD

GPU procedural galaxy seeding with spiral arms and embedded solar systems. LOD system for sphere-to-billboard transitions. Basic accretion disks. ImGui master demo menu.

Galaxy Seeding LOD System Accretion Disk Demo Menu
Phase 4 1–2 Months

SPH & Kilonova Visuals

Smoothed Particle Hydrodynamics for realistic neutron-star interiors. Kilonova explosion rendering. Full gravitational-wave propagation grid with strain visualization.

SPH Kilonova GW Grid Strain Viz
Phase 5 3–6 Months

Pseudo-GR & Real Data

Post-Newtonian / pseudo-GR for black holes. Gravitational lensing. NASA SPICE kernel import for real Solar System ephemeris. Spaceship physics, save/load, multiplayer spectator mode.

Post-Newtonian Lensing NASA SPICE Multiplayer
Phase 6 Long-Term

Relativistic Ray-Tracing & Beyond

Full relativistic ray-tracing. Universe-scale web export via WebGPU. VR support. The endgame: a consumer-grade tool that lets anyone explore a physically accurate universe.

RT Relativistic WebGPU VR Web Export

What Sets It Apart

01

Real Astrophysics, Not a Game Engine

Not a game engine with physics bolted on. A real astrophysics simulator that runs in real time with actual N-body gravitational dynamics on the GPU.

02

Live Neutron-Star Mergers

The only consumer-grade engine with live neutron-star mergers and visible gravitational waves. Watch compact objects spiral, collide, and emit detectable GW events in real time.

03

True Universe Scale

Floating-origin + double precision = actual universe scale. No other hobby or research project does this cleanly at interactive framerates with a full N-body solver.

04

One-Click Demoable

Every feature is instantly demoable with a single click. Nine pre-built scenarios from binary neutron-star inspirals to full galaxy evolution. No setup required.

05

Open Architecture

Modular, header-based subsystems. Plug in your own shaders, models, or data. Import NASA SPICE kernels or Gaia star catalogs. Extend without fighting the engine.

03

Get in Touch

Interested in Ikarus? Have ideas about N-body simulation or gravitational-wave rendering? We'd love to hear from you.

hello@proceduralabs.eu