Make name entry on mobile browsers possible

Prior to this change, there wasn't a way in mobile browsers to show
the virtual keyboard in order to enter the player name.

With this change, the name entry is now done via a hidden input field,
which enables the use if a virtual keyboard.

Mobile browsers are not special cased, the desktop browsers will also
use the input field.

front/src/Phaser/Components/TextInput.ts

@@ -1,7 +1,9 @@
+import {HtmlUtils} from "../../WebRtc/HtmlUtils";
 
 export class TextInput extends Phaser.GameObjects.BitmapText {
     private minUnderLineLength = 4;
     private underLine: Phaser.GameObjects.Text;
+    private onChange: (text: string) => void;
 
     constructor(scene: Phaser.Scene, x: number, y: number, maxLength: number, text: string, onChange: (text: string) => void) {
         super(scene, x, y, 'main_font', text, 32);
@@ -10,19 +12,30 @@ export class TextInput extends Phaser.GameObjects.BitmapText {
 
         this.underLine = this.scene.add.text(x, y+1, this.getUnderLineBody(text.length), { fontFamily: 'Arial', fontSize: "32px", color: '#ffffff'})
         this.underLine.setOrigin(0.5)
+        this.onChange = onChange;
 
+        // Use a hidden input field so that on mobile browsers the virtual
+        // keyboard will be displayed
+        const mainContainer = HtmlUtils.getElementByIdOrFail<HTMLDivElement>('main-container');
+        const inputElement = document.createElement('input');
+        inputElement.id = 'playerName';
+        inputElement.maxLength = maxLength
+        // Make sure that now scolling is needed and that the input field is
+        // not visible
+        inputElement.setAttribute('style', 'opacity:0;position:absolute;bottom:0');
+        mainContainer.appendChild(inputElement);
 
-        this.scene.input.keyboard.on('keydown', (event: KeyboardEvent) => {
-            if (event.keyCode === 8 && this.text.length > 0) {
-                this.deleteLetter();
-            } else if ((event.keyCode === 32 || (event.keyCode >= 48 && event.keyCode <= 90)) && this.text.length < maxLength) {
-                this.addLetter(event.key);
-            }
-            this.underLine.text = this.getUnderLineBody(this.text.length);
-            onChange(this.text);
-        });
+        inputElement.addEventListener('input', this.onInput.bind(this)  as EventListener);
     }
-    
+
+    private onInput(event: InputEvent) {
+        const inputElement = <HTMLInputElement>event.target;
+        // Truncate the text to the maximum length, this is needed for mobile
+        // browsers that don't support the input field `maxLength` attribute
+        this.text = inputElement.value.substr(0, inputElement.maxLength)
+        this.onChange(this.text);
+    }
+
     private getUnderLineBody(textLength:number): string {
         if (textLength < this.minUnderLineLength) textLength = this.minUnderLineLength;
         let text = '_______';
@@ -32,15 +45,6 @@ export class TextInput extends Phaser.GameObjects.BitmapText {
         return text;
     }
 
-    private deleteLetter() {
-        this.text = this.text.substr(0, this.text.length - 1);
-    }
-
-
-    private addLetter(letter: string) {
-        this.text += letter;
-    }
-
     getText(): string {
         return this.text;
     }

front/src/Phaser/Login/LoginScene.ts

@@ -1,3 +1,4 @@
+import {HtmlUtils} from "../../WebRtc/HtmlUtils";
 import {gameManager} from "../Game/GameManager";
 import {TextField} from "../Components/TextField";
 import {TextInput} from "../Components/TextInput";
@@ -41,6 +42,22 @@ export class LoginScene extends ResizableScene {
             this.name = text;
         });
 
+        // Mobile Browsers need an input field, so that a virtual keyboard
+        // gets shown
+        const nameInputElement = HtmlUtils.getElementByIdOrFail<HTMLInputElement>('playerName');
+        // As we need an input field for mobile browsers, use it also for
+        // the desktop. Therefore make sure that is has the focus when the page
+        // is loaded, so that all keyboard events are handled by that input
+        // field.
+        nameInputElement.focus()
+        // Mobile browsers won't show the virtual keyboard on page load, hence
+        // re-focus to make it pop up. On desktop browsers it doesn't do any
+        // harm.
+        this.input.on('pointerdown', () => {
+            nameInputElement.blur();
+            nameInputElement.focus();
+        });
+
         this.pressReturnField = new TextField(this, this.game.renderer.width / 2, 130, 'Press enter to start');
 
         this.logo = new Image(this, this.game.renderer.width - 30, this.game.renderer.height - 20, LoginTextures.icon);