Gameable Engine

Read player input ​

Goal ​

Move the player with WASD or the left stick, and fire with the left mouse button or the right trigger — without a key code appearing anywhere in your game code. When you are done, input.axis2('move') drives the character and input.pressed('fire') fires exactly once per click.

Files you will edit ​

  • src/game.ts — declare the bindings.
  • src/systems/move.ts — read the actions.

Steps ​

  1. Declare the action map in src/game.ts. Names are yours; bindings are KeyboardEvent.code values, friendly aliases ('W', 'Space', 'LMB') or Gamepad* names.

    ts
    import { defineGame } from 'gameable';
import { move } from './systems/move';

export default defineGame({
  assets: './assets.json',
  world: 'arena',
  actions: {
    fire: ['LMB', 'GamepadRT'],
    jump: ['Space', 'GamepadA'],
    move: { axis2: ['A', 'D', 'S', 'W'], gamepadAxes: [0, 1] },
  },
  systems: [move],
});

  2. Read them in src/systems/move.ts. axis2 returns [x, y] in -1..1, with +y forward; the tuple is reused every call, so destructure it instead of keeping the reference.

    ts
    import { input, type Ctx } from 'gameable';

const SPEED = 5;

export function move(ctx: Ctx): void {
  const [x, y] = input.axis2('move');
  ctx.player.velocity[0] = x * SPEED;
  ctx.player.velocity[2] = -y * SPEED;

  if (input.pressed('jump')) ctx.player.jump();
}

  3. Use the edge readers, not the held reader, for one-shot actions. pressed('fire') is true on exactly one simulation step per click — including a click that starts and ends between two rendered frames, and however many frames the display drew since the last step — while down('fire') stays true for as long as the button is held, which is what an automatic weapon wants.

    ts
    if (input.pressed('fire')) fireOnce();
if (input.down('fire')) holdTrigger();

  4. For a mouse-look camera, ask for pointer lock and read the frame's delta. Deltas are zero unless the lock is held, so this is safe to run always.

    ts
    import { input, type Ctx } from 'gameable';

const SENSITIVITY = 0.0022;

export function look(ctx: Ctx): void {
  if (input.pressed('fire') && !input.locked) input.requestPointerLock();
  ctx.camera.yaw -= input.mouse.dx * SENSITIVITY;
  ctx.camera.pitch -= input.mouse.dy * SENSITIVITY;
}

Verify ​

sh
npm run dev

Hold W and the player walks forward; the left stick does the same. Click and the weapon fires once per click, not once per frame. Then assert it headlessly:

sh
npm test
ts
// tests/smoke.spec.ts
it('fires once per click', () => {
  harness.mouseDown(0);
  harness.frame();
  expect(harness.shots).toBe(1);
  harness.frame(); // still held, no second shot
  expect(harness.shots).toBe(1);
});

See also ​