— · gen 0Each seed drives a deterministic PRNG (mulberry32). A fractal gradient-noise heightmap is radially faded into an island; a second noise field supplies moisture. Biomes — meadow, forest, rock, sand — come from altitude and moisture. Water is flat at sea level with a wavy shader.
Two living resources: plants scattered in moist meadows/forests, algae patches along the shoreline. Both regrow over time, faster when lit by day and near Tide Sprite trails. Dead organisms drop carrion on the terrain, which scavengers consume.
Every organism carries a genome of 8 floats: size · speed · sense · metabolism · armor · aggression · fertility · nocturnal. The genome shapes the body (scale, legs, spines, head size, tint) and the behavior weights. Each organism has energy, health, age, hunger, fear, and a small memory of its last meal.
Every tick an organism senses nearby entities via a coarse spatial hash (grid cells sized ~4 units). Based on hunger, fear, and mate-readiness, it chooses a state: wander · forage · flee · pursue · mate · rest. States steer velocity toward a target with simple seek/flee/arrive rules and terrain-following over the heightmap.
Mature organisms with high energy seek a same-species mate. On pair-up, offspring inherit each gene from one parent (uniform crossover) with gaussian mutation (σ≈0.08, clamped to valid ranges). Both parents pay an energy cost; newborns appear between them. No fitness function is imposed — selection emerges from who actually survives to breed.
A simulated day is 120 seconds of wall-clock time (scaled by speed). The sun orbits the island, sky tint crossfades from dawn → noon → dusk → night. At night: plants regrow more slowly, Leafers prefer rest, and Stalkers (and any species with a high nocturnal gene) gain up to 60% extra sense range and +20% speed. This creates a genuine selection pressure across the circadian loop.
The world holds up to 420 organisms. When a species exceeds its soft cap, reproduction is suppressed for that species until attrition frees room. Rendering uses simple primitive bodies per organism (low poly) — cheap enough for a few hundred creatures on a laptop. Distant orgs reuse simplified materials.