Vivarium - Ambient Small Life for Every Room, for GameMaker

Fill your GameMaker rooms with the small life a real place has, placed by what the room IS: butterflies and bees over the grass, dragonflies and pond skaters over the water, frogs on the bank that dive when you come near, fish under the surface, moths drawn to your lantern at dusk, fireflies pulsing in the dark, bats overhead at night. 43 species in 9 families, every wing, fin and leg drawn by the package, frame by frame. Pure GML.

A room with nothing moving in it looks like a set. Vivarium learns which of your tiles are water and which are ground, works out the shore itself, and keeps the right life in view for the room and the time of day: it fills the view the moment a room appears, tops it up and thins it as the player walks, and gets out of the player's way.

// Create: 30 x 20 tiles of 32 px, a pond in one corner (your own three questions about a tile)
my_habitat = viv_habitat_build(30, 20, function(_x, _y) { return _x < 8 && _y < 6; }, function(_x, _y) { return true; });
my_world = viv_world_create(my_habitat, { biomes: ["meadow", "pond"], tile_w: 32, tile_h: 32 });
// Step: viv_world_step(my_world, { x: player.x, y: player.y, phase: "dusk" });
// Draw: viv_world_draw(my_world);

What your players see

• 43 species in 9 families: 10 butterflies (Peacock, Swallowtail, Blue Morpho, Red Admiral...), 5 moths (Luna, Garden Tiger, Emperor...), 4 fireflies and glow-worms, 5 dragonflies and damselflies, 4 bees and hoverflies, 6 fish (two koi, a pike, a perch, a minnow shoal...), 4 frogs and toads, 3 bats and 2 pond skaters and whirligigs.
• Each family moves like itself: butterflies flutter and settle with their wings opening and closing; dragonflies dart and hover; frogs sit, croak, hop and dive into the water with a ripple; bats swoop in arcs; skaters push and glide; a minnow shoal follows its leader.
• The time of day: butterflies and bees by day, moths and fireflies at dusk, bats at night. Fireflies of one kind fall into step and flash in waves, and moths orbit your lamp. The fireflies' light is drawn apart from the creatures, so your own night tint never dims it.
• Your own species: a record of a name, a family, a size, three colours, a shape and a pattern, and it lives, animates and flees like the rest.

Built to plug in

• A habitat from three functions of a tile (the tested route), or read from your tilemap by tile index (its refusals are tested; reading a real tile layer is the one path our runs have not exercised). Biomes (meadow, forest, pond, marsh, town, cave) decide which families belong; switch any family off.
• A world struct you step and draw in room coordinates, with your player, your camera view and an optional lamp. Change biomes or density while the room runs, or scatter everything at once.
• Every frame of every species is struck once into one atlas sprite, in slices, so creating a world never stalls a frame (or strike it on a loading screen). After that, about 0.3 ms a frame to step 21 creatures and 0.25 ms to draw them, measured on our machine, VM runtime.
• Seeded: the same seed places the same life. Raw, readable source with a header on every public function.

Tested

• Igor package build clean on the shipped source, and proven able to fail.
• 36 in-engine assertions on a real built exe, held to our RPG Maker MZ original run in Node: a 150-frame world of 12 creatures in all nine families matched EXACTLY, frame by frame, and 304 drawings with exactly the original's 6,280 paint operations.
• 22 more in a blank project that installed the package the way you will and ran the Readme's own code.
• 100 adversarial calls against 25 documented functions with zero crashes.

Requirements

GameMaker 2024.14 or newer (built and tested against runtime 2024.14.4.268, VM). Pure GML: no extensions, no DLLs, no shaders, no sprites. Import the .yymps, open rm_viv_demo, press Play: THE POND, a painted meadow with two ponds, and a lantern-bearer you walk with the arrows; T turns day to dusk to night. Vivarium makes no sound.

One commercial licence, unlimited games, no attribution required. Every creature the package draws in your game is yours to ship, including on your store page and in your trailers.

Paid, from the same studio

• Vivarium for RPG Maker MZ ($12.99): the original, reading your maps' tiles and regions.
• Chitin ($14.99): a specimen cabinet of generated beetles and lepidoptera, for GameMaker - the collection to Vivarium's living meadow.
• Shoal ($14.99): generated fish species, silhouettes and specimen cards, for GameMaker.
• Welkin ($14.99): a time-of-day and weather sky drawn by the package, for GameMaker.

More GameMaker systems at csaf.itch.io.

AI disclosure: the code, the generated artwork and the interface text in this package were produced with AI assistance. Every store image, the cover and the GIF were rendered by the product itself. Type: Libre Baskerville (SIL OFL 1.1), notices included.