diablo2d/js/core/input.js

/* ============================================================
 * Diablo2D — input.js : unified mouse/keyboard state
 * Canvas-only listeners; DOM UI handles its own events.
 * ============================================================ */
'use strict';

window.D2 = window.D2 || {};
(function (D2) {

  const state = {
    mx: 0, my: 0,              // canvas-space cursor
    left: false, right: false, mid: false,
    leftPressed: false,        // true only on frame of press
    rightPressed: false,
    wheelDelta: 0,
    keys: new Set(),           // currently held (KeyboardEvent.code)
    pressedKeys: new Set(),    // pressed this frame
    releasedKeys: new Set(),
    anyKeyPress: false,
    lastMouseWorld: null,
  };

  let canvas = null;
  const _pressedQueueKeys = new Set();
  const _releasedQueueKeys = new Set();

  function init(targetCanvas) {
    canvas = targetCanvas;

    window.addEventListener('keydown', (e) => {
      if (e.repeat) return;
      state.keys.add(e.code);
      _pressedQueueKeys.add(e.code);
      state.anyKeyPress = true;
      // block browser scroll/space navigation during gameplay
      if (['Space', 'ArrowUp', 'ArrowDown', 'Tab'].includes(e.code)) e.preventDefault();
    }, { passive: false });

    window.addEventListener('keyup', (e) => {
      state.keys.delete(e.code);
      _releasedQueueKeys.add(e.code);
    });

    window.addEventListener('blur', () => {
      state.keys.clear();
      state.left = state.right = false;
    });

    canvas.addEventListener('mousemove', (e) => {
      const r = canvas.getBoundingClientRect();
      state.mx = e.clientX - r.left;
      state.my = e.clientY - r.top;
      /* authoritative resync: if the browser says buttons are up, believe it.
         Heals a missed mouseup (released outside the window, alt-tab, etc.) */
      if (typeof e.buttons === 'number') {
        if (!(e.buttons & 1)) state.left = false;
        if (!(e.buttons & 2)) state.right = false;
        if (!(e.buttons & 4)) state.mid = false;
      }
    });

    canvas.addEventListener('mousedown', (e) => {
      updateMousePos(e);
      if (e.button === 0) { state.left = true; state.leftPressed = true; }
      if (e.button === 2) { state.right = true; state.rightPressed = true; }
      if (e.button === 1) { state.mid = true; e.preventDefault(); }
    });

    const releaseAll = () => { state.left = false; state.right = false; state.mid = false; };
    window.addEventListener('mouseup', (e) => {
      if (e.button === 0) state.left = false;
      if (e.button === 2) state.right = false;
      if (e.button === 1) state.mid = false;
    });
    /* cursor left the page / OS took the pointer / touch cancelled */
    document.documentElement.addEventListener('mouseleave', releaseAll);
    window.addEventListener('pointercancel', releaseAll);
    document.addEventListener('visibilitychange', () => {
      if (document.hidden) releaseAll();
    });

    canvas.addEventListener('contextmenu', (e) => e.preventDefault());

    canvas.addEventListener('wheel', (e) => {
      state.wheelDelta += Math.sign(e.deltaY);
      e.preventDefault();
    }, { passive: false });

    window.addEventListener('mousedown', (e) => {   // audio unlock gesture
      D2.audio && D2.audio.unlock();
    }, { once: false, capture: true });
  }

  function updateMousePos(e) {
    const r = canvas.getBoundingClientRect();
    state.mx = e.clientX - r.left;
    state.my = e.clientY - r.top;
  }

  /** call at end of each simulation frame */
  function endFrame() {
    state.leftPressed = false;
    state.rightPressed = false;
    state.wheelDelta = 0;
    state.pressedKeys.clear();
    state.releasedKeys.clear();
    for (const k of _pressedQueueKeys) state.pressedKeys.add(k);
    for (const k of _releasedQueueKeys) state.releasedKeys.add(k);
    _pressedQueueKeys.clear();
    _releasedQueueKeys.clear();
    state.anyKeyPress = false;
  }

  const isDown = code => state.keys.has(code);
  const wasPressed = code => state.pressedKeys.has(code);
  const wasReleased = code => state.releasedKeys.has(code);

  /* virtual press used by UI hotbar buttons */
  function injectPress(code) {
    _pressedQueueKeys.add(code);
  }

  D2.input = { state, init, endFrame, isDown, wasPressed, wasReleased, injectPress };
})(window.D2);