Aava: an open world that comes alive as you build in it

Aava is a 3D exploration and building game for children, written in GDScript on Godot 4. The valley is a pure function of one integer seed: the ground, the river, the forest and the mountains are computed rather than stored, so nothing about the world has to be saved, sent between two machines playing together, or loaded from a file. What is saved is only what a child has changed.

The loop is creation rather than collection. Everything built makes the valley more alive, and the more alive it is the more it gives back: plant a grove and birds arrive, feed an animal and it becomes a friend, raise a house with a bed and a fire and it becomes somewhere to spend the night. Coins come from looking after things, and are spent on tools that widen what a child can reach — an axe, shears, a lantern, a bicycle, a quad — rather than on numbers going up.

There is a fairground across the river with a carousel, two moving walkways, a trampoline, a thirty-metre wheel and a wooden coaster whose speed is integrated from the slope of its own track; a bridge, because a machine on wheels cannot ford a river; and street signs where the four roads meet, each turned by asking where its road actually goes.

It is played on a phone by two brothers, aged ten and six, and nearly every change in its history began with one of them saying what looked wrong. The test suite is written the same way round: each check corresponds to a bug that actually happened, and says in its own words what the wrong version looked like, so a regression is recognised rather than merely detected.

The code is AGPL-3.0-or-later. The name Aava, the application id and the icon are reserved and are not covered by that licence; see NOTICE.md.