transmute / core

The Transmute library

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Good places to start21 results
Getting startedInstall the engine and build your first game.GuidesArchitectureUnderstand the engine, managers, and game loop.GuidesExamplesStart with a working platformer, RPG, or hello world.GuidesHeadless testingVerify gameplay without opening a window.GuidesAPI overviewExplore the building blocks of the engine.APIGame lifecycleConfigure, initialize, update, and render your game.APIAssets and manifestsLoad sprites, fonts, and audio with GameSpec.APIWorlds and physicsBuild tile worlds, movement, and collision.APIHeadless harnessSimulate input and assert frames and audio.APIhello worldA hands-on walkthrough of hello world.Tutorialssprites and animationA hands-on walkthrough of sprites and animation.Tutorialsinput and movementA hands-on walkthrough of input and movement.Tutorialscollision detectionA hands-on walkthrough of collision detection.Tutorialsstate managementA hands-on walkthrough of state management.Tutorialsaudio systemA hands-on walkthrough of audio system.Tutorialslevel designA hands-on walkthrough of level design.TutorialsAuthoring gamesTurn a prompt and assets into a verified game.GuidesCookbookFind practical recipes for common game features.GuidesContributingSet up Flox and run the project checks.GuidesWebsite developmentDevelop, preview, and deploy this website.GuidesCLI distributionBuild and distribute the game scaffolding CLI.Guides
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Cookbook

Short recipes for Transmute Core. For agent automation, start with AGENTS.md and examples/java/hello.

Headless verify one frame

GameConfig config = new GameConfig.Builder()
    .title("Smoke").version("0").size(160, 90).scale(1)
    .headless(true).showStartScreen(false).build();

try (GameHarness harness = GameHarness.of(() -> new MyGame(config))) {
    harness.step(1);
    FrameAssert.assertPixel(harness.renderer(), 0, 0, expectedColor);
}

Load assets from a manifest

# src/main/resources/gamespec.properties
title=My Game
width=320
height=180
font=fonts/font.png
image.player=sprites/player.png

Manager manager = getManager();
manager.bootstrapDefaults();
GameSpec.loadClasspath("gamespec.properties").loadAssets(manager.getAssetManager());

Script input in headless mode

SimulatedInput input = (SimulatedInput) harness.game().getManager().getInputHandler();
input.pressKey(KeyEvent.VK_SPACE);
harness.step(1);

States

StateManager states = manager.getStateManager();
states.push(new PlayState(...));
states.pop(); // leave current state

Playtest scripts

# playtests/jump.script
0 press SPACE
1 release SPACE
4 idle

PlaytestScript.loadClasspath("playtests/jump.script")
    .play(harness, (SimulatedInput) game.getManager().getInputHandler());

Assert audio cues (headless)

try (AudioProbe probe = AudioProbe.install()) {
    AudioPlayer.setMuted(true);
    AudioPlayer.play("jump");
    probe.assertPlayed("jump");
}

Probe records even when muted or when the clip is missing from the AssetManager.

Declarative spawns / triggers

spawn.player=2,2
spawn.player.color=100,150,255
trigger.coin=6,2
trigger.coin.audio=pickup
state.initial=play

World world = spec.createWorld();
world.findTrigger("coin").setOnEnter(a -> score++);
World.Actor marker = world.findActor("player");

Record a playtest

PlaytestRecorder rec = new PlaytestRecorder();
rec.hold(KeyEvent.VK_D);
harness.step(20); rec.advance(20);
rec.release(KeyEvent.VK_D);
rec.write(Path.of("playtests/walk.script"));

Sprite atlas

SpriteAtlas atlas = SpriteAtlas.fromAsset(assets, "sheet-player", 16);
Animation walk = atlas.animation("walk", 150, 0,0, 1,0, 2,0);

Tile world (top-down)

World world = World.grid(20, 15, 16).clearColor(bg).solidColor(wall);
world.fillBorder(World.SOLID);
world.setTile(5, 7, World.SOLID);
World.Actor player = World.Actor.colored(32, 32, 16, 16, color);
world.add(player);
player.tryMove(2, 0); // rejects if solids block

Or from GameSpec (world.cols, world.rows, world.border, world.solid=5,7;6,7):

World world = GameSpec.loadClasspath("gamespec.properties").createWorld();

See examples/java/rpg.

Platformer body

Body2D body = new Body2D(x, y, 16, 16);
body.setVelocityX(3);
body.jump();
body.step(platforms); // platforms implement Body2D.Solid

See examples/java/platformer.

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