Tutorial 3: Input and Movement

Drive a character with IInputHandler so the same code works under SimulatedInput headless.

What you'll learn

isKeyPressed / isKeyHeld / isKeyReleased
manager.getInputHandler() (required for headless)
Top-down move with World.Actor, or free movement
PlaytestScript for data-driven input

Input states

Method	When true
`isKeyPressed`	First frame of the press
`isKeyHeld`	Every frame while down
`isKeyReleased`	First frame after release

Always use manager.getInputHandler(), not only getInput(), so GameHarness can inject SimulatedInput.

Top-down (preferred)

Copy examples/java/rpg Player:

var input = manager.getInputHandler();
int dx = 0, dy = 0;
if (input.isKeyHeld(KeyEvent.VK_A, KeyEvent.VK_LEFT)) dx -= speed;
if (input.isKeyHeld(KeyEvent.VK_D, KeyEvent.VK_RIGHT)) dx += speed;
if (input.isKeyHeld(KeyEvent.VK_W, KeyEvent.VK_UP)) dy -= speed;
if (input.isKeyHeld(KeyEvent.VK_S, KeyEvent.VK_DOWN)) dy += speed;
if (dx != 0) tryMove(dx, 0);
if (dy != 0) tryMove(0, dy);

World.Actor.tryMove rejects moves blocked by solid tiles.

Headless script

src/main/resources/playtests/walk.script:

0 hold D
20 release D
22 idle

try (GameHarness harness = GameHarness.of(() -> new Game(headlessConfig))) {
    SimulatedInput input = (SimulatedInput) harness.game().getManager().getInputHandler();
    PlaytestScript.loadClasspath("playtests/walk.script").play(harness, input);
}

Or press once in code:

input.pressKey(KeyEvent.VK_SPACE);
harness.step(1);

Platformer movement

Use Body2D (next tutorial / examples/java/platformer) instead of hand-rolled gravity.

Tutorial 4: Collision Detection

Find your next step.