Role & Objective You are an expert graphics programmer spec...

Prompt

Role & Objective You are an expert graphics programmer specializing in real-time 3D astronomy visualization (WebGL/WebGPU, Three.js/Babylon.js, or Unreal/Unity — choose the stack that best achieves photorealism in a browser). Build a complete, fully interactive Milky Way galaxy simulation that runs at 60 FPS, where the user can seamlessly zoom from a galactic view (100,000+ light-years across) down to individual planets, land on/visit them, and explore star clusters, nebulae, and the solar system — all with realistic, scientifically plausible visuals. 1. Galaxy-Scale Requirements Render the Milky Way with 100,000–500,000 procedurally generated stars using GPU instancing / point clouds with additive blending, sized and colored by stellar class (O/B blue, A/F white, G yellow like the Sun, K orange, M red dwarfs — follow real spectral distribution: ~76% M-dwarfs, etc.). Model galactic structure accurately: central bulge, bar, 4 major spiral arms (Perseus, Scutum–Centaurus, Sagittarius, Norma/Outer), inter-arm regions, thin/thick disk, and halo with globular clusters. Render the galactic core with a bright, glowing supermassive black hole region (Sagittarius A*) surrounded by dense star fields and an accretion glow effect. Include nebulae (emission: red/pink H-II regions; reflection: blue; dark: Bok globules) as volumetric billboards with soft particle systems. Place recognizable nebulae: Orion Nebula, Eagle Nebula, Carina Nebula, and the Pillars of Creation. Include star clusters: open clusters (Pleiades with visible blue reflection nebulosity, Hyades) and ~150 globular clusters scattered in the halo. Add a subtle dark matter / dust lane effect using occluding dust particles along the galactic plane. Milky Way backdrop: procedurally generated skybox based on real all-sky survey imagery (use Milky Way panorama textures from NASA/ESA public domain as fallback). 2. Zoom & Camera — The Core Experience Implement seamless multi-scale navigation across 8 orders of magnitude: from 100,000 ly (full galaxy) → 1,000 ly (arm scale) → 1 ly (star system) → 1 AU (orbital view) → 100,000 km (planet approach) → 1 km (surface flythrough). Use a logarithmic depth buffer (or camera-relative rendering) to eliminate z-fighting at all scales. Smooth camera interpolation: scroll-wheel/pinch zoom with inertial easing; double-click to fly to any star, planet, or cluster; a Star Trek warp star-streak transition effect between major scale jumps. Camera modes: free-flight (WASD + mouse), orbit around selected object, cinematic auto-tour mode, and cockpit/first-person on planet surfaces. HUD scale indicator showing current zoom level (ly → AU → km) and distance from Sol. 3. The Solar System — Fully Visitable Include all 8 planets + Pluto, the Sun, and major moons (Earth's Moon, Mars' Phobos/Deimos, Galilean moons, Titan, Enceladus, Triton), each rendered with: Real NASA texture maps (public domain): color, bump/normal, specular, cloud, and night-lights maps where available. Correct relative sizes, orbital distances (compressed where necessary with a toggle), axial tilts, rotation periods, and orbital eccentricities. Realistic atmospheres: Earth's blue Rayleigh scattering with sunset rim glow; Venus' thick yellow haze; Mars' thin dusty sky (butterscotch daytime, blue sunsets); Titan's orange methane atmosphere. Earth specifics: animated cloud layer, city lights on the night side, aurora at poles, specular ocean reflections. Saturn/Jupiter rings: Saturn with Cassini Division, ring shadows on the planet and planet shadow on rings; Jupiter's Great Red Spot with turbulent shader animation. Sun: animated surface with granulation shader, corona, solar flares, and lens flare; correct brightness falloff (planets lit realistically by distance). Asteroid belt (~5,000 instanced asteroids) and Kuiper Belt as sparse particle ring; Oort Cloud as a faint sphere at galactic view. 4. Procedural Exoplanet Generation Every star beyond Sol is visitable: procedurally generate plausible exoplanet systems on approach using seeded RNG (same star → same system every session). Generate based on star class: terrestrial rocky worlds, ocean worlds, lava planets, ice worlds, gas giants with bands and storms, tidally locked worlds with terminator zones, ringed worlds. Procedural terrain for rocky planets: continent-shaped noise (simplex/fBm), mountain ranges, canyons, river networks, polar ice caps, cratered surfaces — generated via GPU displacement/LOD quadtree so users can fly down to the surface. Realistic day/night cycles, weather (clouds, storms), and optional simple atmosphere scattering shader per planet. Show TRAPPIST-1, Kepler-452b, and Proxima Centauri b as hand-crafted special systems matching known scientific data. 5. Visual Quality & Realism Rendering: PBR materials, HDR pipeline with bloom (stars, core, nebulae), tonemapping (ACES filmic), lens flares, god rays for close star flybys, volumetric lighting near the core. Physics plausibility: accurate star colors from blackbody temperatures (3,000K red → 25,000K blue), correct galactic rotation (differential rotation with flat rotation curve, ~225 Myr period at Sol's radius), real constellation of notable named stars (Sol, Sirius, Betelgeuse, Rigel, Vega, Antares, Alpha Centauri) at approximately correct relative positions. Space ambience: subtle ambient starlight, no sound in vacuum except UI + optional cinematic score + radio static for realism. Support 4K resolution, and a cinematic screenshot mode. 6. UI / UX Features Object search with autocomplete (search any planet, star, cluster, nebula). Info panel per object: name, type, mass, radius, temperature, distance, orbital data, fun facts — with a Fly here button. Time controls: pause, 1× → 1,000,000× speed (watch orbits), reverse time, and jump to date. Toggle overlays: orbits on/off, labels on/off, distance scale realistic/compressed, constellations from Earth's view. Minimap breadcrumb showing your current location in the galactic hierarchy (Galaxy → Arm → System → Planet). Bookmark/favorites system; guided tour of the 10 must-see locations. Mobile-friendly touch controls; works on desktop first. 7. Technical Constraints Target: browser-based (Three.js + WebGPU/WebGL2 preferred) as a single deployable web app; 60 FPS on a mid-range GPU, graceful LOD fallback for low-end devices. All data embedded or CDN-loaded; textures from NASA/ESA public domain sources with attribution screen. No login required. Runs offline after first load (service worker caching) if possible. Clean, commented, modular code: separate modules for galaxy generation, star systems, planet rendering, camera/LOD manager, UI. Provide setup instructions, a performance budget breakdown, and a list of known scientific compromises made for gameplay/visuals. Deliverable: A complete runnable project with all source files, a README, and a live-preview build. Prioritize the zoom-from-galaxy-to-planet seamless experience above all else — that is the wow moment.