feat: add mobile virtual touch controls

- document.js: add is_touch detection and virtual button CSS
- input.js: create virtual D-pad + action buttons + touch drag camera
- main.js: skip Pointer Lock on touch devices

source/input.js

@@ -81,3 +81,72 @@ c.onmouseup = (ev) => {
 	keys[key_action + ev.button] = 0;
 };
 
+// ─── Mobile virtual controls ───
+
+if (is_touch) {
+	let ctrl = document.createElement('div');
+	ctrl.id = 'ctrl';
+	ctrl.innerHTML =
+		'<div id="ctrl-left">'+
+			'<button class="ctrl-btn" id="btn-up">▲</button>'+
+			'<button class="ctrl-btn" id="btn-left">◀</button>'+
+			'<button class="ctrl-btn" id="btn-right">▶</button>'+
+			'<button class="ctrl-btn" id="btn-down">▼</button>'+
+		'</div>'+
+		'<div id="ctrl-right"></div>'+
+		'<div id="ctrl-actions">'+
+			'<button class="ctrl-btn ctrl-shoot" id="btn-shoot">⚡</button>'+
+			'<button class="ctrl-btn ctrl-prev" id="btn-prev">◀◀</button>'+
+			'<button class="ctrl-btn ctrl-next" id="btn-next">▶▶</button>'+
+			'<button class="ctrl-btn ctrl-jump" id="btn-jump">▲</button>'+
+		'</div>';
+	document.getElementById('g').appendChild(ctrl);
+
+	// Prevent touches from reaching the canvas
+	ctrl.addEventListener('touchstart', (e) => e.preventDefault(), {passive: false});
+	ctrl.addEventListener('touchmove', (e) => e.preventDefault(), {passive: false});
+
+	// Bind button press/release
+	let bindBtn = (id, keyIndex) => {
+		let el = document.getElementById(id);
+		el.addEventListener('touchstart', () => { keys[keyIndex] = 1; });
+		el.addEventListener('touchend', () => { keys[keyIndex] = 0; });
+		el.addEventListener('touchcancel', () => { keys[keyIndex] = 0; });
+	};
+	bindBtn('btn-up', 1);
+	bindBtn('btn-down', 3);
+	bindBtn('btn-left', 2);
+	bindBtn('btn-right', 4);
+	bindBtn('btn-shoot', 7);
+	bindBtn('btn-jump', 9);
+	bindBtn('btn-prev', 5);
+	bindBtn('btn-next', 6);
+
+	// Right zone touch drag → camera
+	let rightZone = document.getElementById('ctrl-right'),
+		touch_id = null,
+		last_tx = 0,
+		last_ty = 0;
+	rightZone.addEventListener('touchstart', (e) => {
+		let t = e.changedTouches[0];
+		touch_id = t.identifier;
+		last_tx = t.clientX;
+		last_ty = t.clientY;
+	});
+	rightZone.addEventListener('touchmove', (e) => {
+		for (let t of e.changedTouches) {
+			if (t.identifier === touch_id) {
+				mouse_x += t.clientX - last_tx;
+				mouse_y += t.clientY - last_ty;
+				last_tx = t.clientX;
+				last_ty = t.clientY;
+			}
+		}
+	});
+	rightZone.addEventListener('touchend', (e) => {
+		for (let t of e.changedTouches) {
+			if (t.identifier === touch_id) touch_id = null;
+		}
+	});
+}
+