The simulation step, SimulateFrame() , is a masterpiece of parallelization and compromise. The code is littered with #pragma omp parallel for directives, attempting to split the screen into vertical slices. However, a legendary comment, said to be written by lead developer Petri "Arvi" Purho, appears above the fluid dynamics solver:
// return world; // Disabled. Causes the universe to end. Reading the Noita source code is a lesson in humility. It is not elegant. It is not safe. It is not what you would teach in a software engineering class. It is a living, bleeding artifact of passionate creation—where performance was sacrificed for possibility, stability for surprise, and sanity for art. noita source code
// Select a spell from the pool based on "cast_delay" and "reload_time" modifiers. // The more negative the modifier, the more likely a "god" spell appears. // - Arvi, 2020. "If it breaks the game, it's a feature." The code doesn't just pick spells. It picks combinations . A separate genetic algorithm runs during world generation, attempting to "breed" synergistic spells. The source records "interesting" combinations in a hidden cache. That's why you sometimes find a wand that fires a homing, acid-infused, ten-cast bubble burst—the algorithm found it amusing. The simulation step, SimulateFrame() , is a masterpiece