fix(mobile): hide screen sharing in native webviews

mobile/README.md

@@ -72,7 +72,12 @@ The WebView configuration is set to:
 - `androidScheme: https` — ensures WebRTC and cookies work correctly on Android
 - `contentInset: always` — iOS safe area respected so game UI is not obscured by notch
 
-Camera and microphone permission requests are handled natively by each platform. See platform READMEs in `android/` and `ios/` once those PRs land.
+Camera and microphone permission requests are handled natively by each platform. iframe allow policies continue to pass through from the web app (`allowPolicy` / `allow` attributes), so existing WA scripting API and embedded-site behavior stays in the server-rendered app.
+
+Known mobile limitation:
+- Screen sharing stays browser-only. Android WebView and WKWebView do not provide a reliable `getDisplayMedia` path for the Universe shell, so the front-end hides the screen-share control when running inside the Capacitor app instead of presenting a broken prompt.
+
+See platform READMEs in `android/` and `ios/` once those PRs land.
 
 ## Fastlane
 

play/src/front/Stores/ScreenSharingStore.ts

@@ -1,6 +1,7 @@
 import type { Readable } from "svelte/store";
 import { get, derived, readable, writable } from "svelte/store";
 import type { DesktopCapturerSource } from "../Interfaces/DesktopAppInterfaces";
+import { isNativeMobileApp } from "../WebRtc/DeviceUtils";
 import { localUserStore } from "../Connection/LocalUserStore";
 import LL from "../../i18n/i18n-svelte";
 import { isSpeakerStore, type LocalStreamStoreValue } from "./MediaStore";
@@ -140,6 +141,10 @@ export const screenSharingConstraintsStore = derived(
 );
 
 export function isScreenSharingSupported(): boolean {
+    if (isNativeMobileApp()) {
+        return false;
+    }
+
     if (window.WAD?.getDesktopCapturerSources) {
         return true;
     }

play/src/front/WebRtc/DeviceUtils.test.ts

@@ -0,0 +1,81 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { isScreenSharingSupported } from "../Stores/ScreenSharingStore";
+import { getNativeAppPlatform, isNativeMobileApp } from "./DeviceUtils";
+
+type TestCapacitor = {
+    getPlatform?: () => "android" | "ios" | "web";
+    isNativePlatform?: () => boolean;
+};
+
+const originalCapacitor = (window as typeof window & { Capacitor?: TestCapacitor }).Capacitor;
+const originalMediaDevices = navigator.mediaDevices;
+
+function setCapacitor(capacitor?: TestCapacitor) {
+    Object.defineProperty(window, "Capacitor", {
+        configurable: true,
+        value: capacitor,
+    });
+}
+
+function setMediaDevices(mediaDevices: MediaDevices | undefined) {
+    Object.defineProperty(window.navigator, "mediaDevices", {
+        configurable: true,
+        value: mediaDevices,
+    });
+}
+
+afterEach(() => {
+    setCapacitor(originalCapacitor);
+    setMediaDevices(originalMediaDevices);
+    vi.restoreAllMocks();
+});
+
+describe("DeviceUtils", () => {
+    it("detects Capacitor native mobile platforms", () => {
+        setCapacitor({
+            getPlatform: () => "android",
+            isNativePlatform: () => true,
+        });
+
+        expect(getNativeAppPlatform()).toBe("android");
+        expect(isNativeMobileApp()).toBe(true);
+    });
+
+    it("treats web or missing Capacitor bridge as non-native", () => {
+        setCapacitor({
+            getPlatform: () => "web",
+            isNativePlatform: () => false,
+        });
+
+        expect(getNativeAppPlatform()).toBeUndefined();
+        expect(isNativeMobileApp()).toBe(false);
+
+        setCapacitor(undefined);
+
+        expect(getNativeAppPlatform()).toBeUndefined();
+        expect(isNativeMobileApp()).toBe(false);
+    });
+});
+
+describe("isScreenSharingSupported", () => {
+    it("hides screen sharing inside native Capacitor apps", () => {
+        setCapacitor({
+            getPlatform: () => "ios",
+            isNativePlatform: () => true,
+        });
+        setMediaDevices({
+            getDisplayMedia: vi.fn(),
+        } as unknown as MediaDevices);
+
+        expect(isScreenSharingSupported()).toBe(false);
+    });
+
+    it("keeps screen sharing available in regular browsers with getDisplayMedia", () => {
+        setCapacitor(undefined);
+        setMediaDevices({
+            getDisplayMedia: vi.fn(),
+        } as unknown as MediaDevices);
+
+        expect(isScreenSharingSupported()).toBe(true);
+    });
+});

play/src/front/WebRtc/DeviceUtils.ts

@@ -28,6 +28,41 @@ export function isAndroid(): boolean {
     return window.navigator.userAgent.includes("Android");
 }
 
+type CapacitorPlatform = "android" | "ios" | "web";
+
+type CapacitorGlobal = {
+    Capacitor?: {
+        getPlatform?: () => CapacitorPlatform;
+        isNativePlatform?: () => boolean;
+    };
+};
+
+function getCapacitorBridge() {
+    return (window as typeof window & CapacitorGlobal).Capacitor;
+}
+
+export function getNativeAppPlatform(): Exclude<CapacitorPlatform, "web"> | undefined {
+    const capacitor = getCapacitorBridge();
+    const platform = capacitor?.getPlatform?.();
+
+    if (!platform || platform === "web") {
+        return undefined;
+    }
+
+    return platform;
+}
+
+export function isNativeMobileApp(): boolean {
+    const capacitor = getCapacitorBridge();
+    const nativePlatform = getNativeAppPlatform();
+
+    if (nativePlatform) {
+        return capacitor?.isNativePlatform?.() ?? true;
+    }
+
+    return false;
+}
+
 export function isFirefox(): boolean {
     return window.navigator.userAgent.toLowerCase().indexOf("firefox") !== -1;
 }