gamepad support

app/src/js/gamepad.ts

@@ -0,0 +1,64 @@
+////
+// Support for gamepads.
+// Maps incoming gamepad button presses to keyboard buttons.
+// 
+
+const BUTTONS = [
+  "A", "B", "X", "Y",
+  "LB", "RB", "LT", "RT",
+  "Select", "Start",
+  "LStick", "RStick",
+  "DPad Up", "DPad Down", "DPad Left", "DPad Right"
+]
+
+const BUTTONS_TO_KEYS: Record<number, string> = {
+  0: "z",   // A → Z
+  1: "x",   // B → X
+  2: "c",   // X → C
+  3: "v",   // Y → V
+  12: "ArrowUp",
+  13: "ArrowDown",
+  14: "ArrowLeft",
+  15: "ArrowRight",
+  9: "Enter",  // Start
+  8: "Escape"  // Select
+}
+
+const activePads = new Set<number>()
+const prevState: Record<number, boolean[]> = {}
+
+export function initGamepad() {
+  window.addEventListener("gamepadconnected", e => {
+    console.log("Gamepad connected:", e.gamepad)
+    activePads.add(e.gamepad.index)
+    requestAnimationFrame(handleGamepad)
+  })
+
+  window.addEventListener("gamepaddisconnected", e => {
+    console.log("Gamepad disconnected:", e.gamepad)
+    activePads.delete(e.gamepad.index)
+  })
+}
+
+function handleGamepad() {
+  const pads = navigator.getGamepads()
+  for (const gp of pads) {
+    if (!gp) continue
+    if (!prevState[gp.index]) prevState[gp.index] = gp.buttons.map(() => false)
+
+    gp.buttons.forEach((btn, i) => {
+      const was = prevState[gp.index]![i]
+      const is = btn.pressed
+      if (was !== is) {
+        const key = BUTTONS_TO_KEYS[i]
+        if (key) {
+          const type = is ? "keydown" : "keyup"
+          window.dispatchEvent(new KeyboardEvent(type, { code: key, key }))
+        }
+        prevState[gp.index]![i] = is
+      }
+    })
+  }
+
+  requestAnimationFrame(handleGamepad)
+}

app/src/js/main.ts

@@ -2,6 +2,7 @@ import { initCompletion } from "./completion.js"
 import { initCursor } from "./cursor.js"
 import { initEditor } from "./editor.js"
 import { initFocus } from "./focus.js"
+import { initGamepad } from "./gamepad.js"
 import { initHistory } from "./history.js"
 import { initHyperlink } from "./hyperlink.js"
 import { initInput } from "./input.js"
@@ -13,6 +14,7 @@ initCompletion()
 initCursor()
 initFocus()
 initEditor()
+initGamepad()
 initHistory()
 initHyperlink()
 initInput()