use zsnes default keybindings for keyboard control

main.js

@@ -23,10 +23,7 @@ class Input {
     this.select = false;
     this.start = false;
 
-    this.upArrowPressed = false;
-    this.downArrowPressed = false;
-    this.leftArrowPressed = false;
-    this.rightArrowPressed = false;
+    this.keysPressed = {};
 
     window.addEventListener('gamepadconnected', this.gamepadConnected);
     window.addEventListener('gamepaddisconnected', this.gamepadDisconnected);
@@ -35,61 +32,48 @@ class Input {
   }
 
   keyDown(e) {
-    if (e.key == 'ArrowUp' || e.key == 'w') {
-      this.upArrowPressed = true;
-    }
-    if (e.key == 'ArrowDown' || e.key == 's') {
-      this.downArrowPressed = true;
-    }
-    if (e.key == 'ArrowLeft' || e.key == 'a') {
-      this.leftArrowPressed = true;
-    }
-    if (e.key == 'ArrowRight' || e.key == 'd') {
-      this.rightArrowPressed = true;
-    }
+    this.keysPressed[e.key] = true;
   }
 
   keyUp(e) {
-    if (e.key == 'ArrowUp' || e.key == 'w') {
-      this.upArrowPressed = false;
-    }
-    if (e.key == 'ArrowDown' || e.key == 's') {
-      this.downArrowPressed = false;
-    }
-    if (e.key == 'ArrowLeft' || e.key == 'a') {
-      this.leftArrowPressed = false;
-    }
-    if (e.key == 'ArrowRight' || e.key == 'd') {
-      this.rightArrowPressed = false;
-    }
+    this.keysPressed[e.key] = false;
   }
 
   update() {
-    // TODO: have a config screen instead of hard-coding the 8Bitdo SNES30 pad.
-    // TODO: handle connects / disconnects more correctly.
-
-    this.up = this.upArrowPressed;
-    this.down = this.downArrowPressed;
-    this.left = this.leftArrowPressed;
-    this.right = this.rightArrowPressed;
+    // Default ZSNES keybindings. See:
+    // http://zsnes-docs.sourceforge.net/html/readme.htm#default_keys
+    this.up = this.keysPressed['ArrowUp'];
+    this.down = this.keysPressed['ArrowDown'];
+    this.left = this.keysPressed['ArrowLeft'];
+    this.right = this.keysPressed['ArrowRight'];
+    this.start = this.keysPressed['Enter'];
+    this.select = this.keysPressed['Shift'];
+    this.a = this.keysPressed['x'];
+    this.b = this.keysPressed['z'];
+    this.x = this.keysPressed['s'];
+    this.y = this.keysPressed['a'];
+    this.l = this.keysPressed['d'];
+    this.r = this.keysPressed['c'];
 
     const gamepad = navigator.getGamepads()[0];
     if (gamepad == null || !gamepad.connected || gamepad.axes.length < 2 ||
         gamepad.buttons.length < 12) {
       return;
     }
+    // TODO: have a config screen instead of hard-coding the 8Bitdo SNES30 pad.
+    // TODO: handle connects / disconnects more correctly.
     this.up |= gamepad.axes[1] < 0;
     this.down |= gamepad.axes[1] > 0;
     this.left |= gamepad.axes[0] < 0;
     this.right |= gamepad.axes[0] > 0;
-    this.a = gamepad.buttons[0].pressed;
-    this.b = gamepad.buttons[1].pressed;
-    this.x = gamepad.buttons[3].pressed;
-    this.y = gamepad.buttons[4].pressed;
-    this.l = gamepad.buttons[6].pressed;
-    this.r = gamepad.buttons[7].pressed;
-    this.select = gamepad.buttons[10].pressed;
-    this.start = gamepad.buttons[11].pressed;
+    this.a |= gamepad.buttons[0].pressed;
+    this.b |= gamepad.buttons[1].pressed;
+    this.x |= gamepad.buttons[3].pressed;
+    this.y |= gamepad.buttons[4].pressed;
+    this.l |= gamepad.buttons[6].pressed;
+    this.r |= gamepad.buttons[7].pressed;
+    this.select |= gamepad.buttons[10].pressed;
+    this.start |= gamepad.buttons[11].pressed;
     debug(this.toString());
   }