Light

In Minecraft, light is a crucial mechanic affecting visibility, mob spawning, and plant growth. The game uses three main lighting systems: light level, internal light level, and rendered brightness. Light levels range from 0 to 15, with 0 being the darkest and 15 the brightest, originating from the sky and certain light-emitting blocks. Block light is produced by light-emitting blocks and spreads using a flood fill algorithm, with its intensity decreasing with distance from the source. Sky light is 15 during clear daytime and doesn't decrease at night, though mob spawning is determined by internal light values. Opaque blocks block sky light, while transparent blocks have no effect, and light-filtering blocks diminish it. Internal light level is used for in-game calculations, impacting mob spawning, plant growth, and daylight sensor outputs, determined by sky light, time, and weather. Rendered brightness is calculated based on light level, time, and weather, dictating the final brightness of blocks and entities. The game also has a smooth lighting system, which blends light levels to generate more realistic shadows and glows. In addition, there is a special 'light block', an invisible block that allows map makers to generate any light level from 0 to 15, facilitating custom map lighting effects.