fix(tinyplace): give the world renderer a WebGL context on Linux (#4213)

app/src-tauri/src/lib.rs

@@ -2009,21 +2009,37 @@ fn append_platform_cef_gpu_workarounds(
 ) {
     // Issue #1697: on Arch/Manjaro-family Linux systems, the AppImage can
     // abort during CEF GPU process startup when EGL context creation fails
-    // before Chromium's own fallback path gets a usable renderer. Disable the
-    // hardware GPU path on Linux so packaged builds can still launch via
-    // software compositing. Users with working GPU stacks can opt back into
-    // hardware acceleration via `OPENHUMAN_FORCE_GPU=1` — required for the
-    // Rive mascot on the Human tab and any other WebGL2 surface to render.
+    // before Chromium's own fallback path gets a usable renderer.
+    //
+    // The original workaround disabled the GPU path with `--disable-gpu`, but
+    // that shuts the GPU process down entirely — and with it every WebGL
+    // surface. That regressed Tiny Place (#4193): the world renderer needs a
+    // WebGL2 context, so on every packaged Linux build it failed to initialise
+    // and the world page showed a black screen with "Could not start the world
+    // renderer" (the Rive mascot on the Human tab is collateral damage too).
+    //
+    // Instead of killing the GPU process, pin it to ANGLE's SwiftShader
+    // software backend. SwiftShader is a pure-software rasteriser that needs no
+    // hardware EGL/driver, so it still sidesteps the #1697 EGL-context abort,
+    // while giving WebGL surfaces a working (software) context to render into.
+    // `--disable-gpu-compositing` is preserved so page compositing stays on the
+    // CPU exactly as before; only the lethal `--disable-gpu` is dropped.
+    // `--enable-unsafe-swiftshader` is required because Chromium gates
+    // SwiftShader-backed WebGL behind it (the "unsafe" label is about software
+    // perf, not security). Users with working GPU stacks can still opt into
+    // hardware acceleration via `OPENHUMAN_FORCE_GPU=1`.
     if os == "linux" {
         if cef_force_gpu_enabled(force_gpu_override) {
             log::info!(
-                "[cef-startup] OPENHUMAN_FORCE_GPU set — skipping --disable-gpu / --disable-gpu-compositing (issue #1697). If the app fails to launch with a GPU process abort, unset the env var."
+                "[cef-startup] OPENHUMAN_FORCE_GPU set — skipping SwiftShader software-GL fallback (issue #1697). If the app fails to launch with a GPU process abort, unset the env var."
             );
         } else {
-            args.push(("--disable-gpu", None));
+            args.push(("--use-gl", Some("angle")));
+            args.push(("--use-angle", Some("swiftshader")));
+            args.push(("--enable-unsafe-swiftshader", None));
             args.push(("--disable-gpu-compositing", None));
             log::info!(
-                "[cef-startup] Linux detected: adding --disable-gpu and --disable-gpu-compositing (issue #1697); set OPENHUMAN_FORCE_GPU=1 to re-enable hardware compositing (needed for WebGL2 surfaces like the Rive mascot)"
+                "[cef-startup] Linux detected: forcing ANGLE/SwiftShader software GL so WebGL surfaces (Tiny Place world renderer, Rive mascot) render without the crash-prone hardware GPU process (issues #1697/#4193); set OPENHUMAN_FORCE_GPU=1 for hardware acceleration"
             );
         }
     }

app/src-tauri/src/lib_tests.rs

@@ -314,11 +314,22 @@ fn platform_os_is_macos_on_macos_build() {
 }
 
 #[test]
-fn platform_cef_gpu_workarounds_disable_linux_gpu_path() {
+fn platform_cef_gpu_workarounds_force_swiftshader_on_linux() {
     let mut args = Vec::new();
     append_platform_cef_gpu_workarounds(&mut args, "linux", "x86_64", None);
 
-    assert!(args.contains(&("--disable-gpu", None)));
+    // #4193: the GPU process must NOT be killed outright — `--disable-gpu`
+    // takes every WebGL surface (the Tiny Place world renderer) down with it.
+    assert!(
+        !args.contains(&("--disable-gpu", None)),
+        "--disable-gpu kills WebGL and must not be set, got: {args:?}"
+    );
+    // Instead the GPU process is pinned to ANGLE/SwiftShader software GL, which
+    // keeps WebGL available while still avoiding the #1697 hardware-EGL abort.
+    assert!(args.contains(&("--use-gl", Some("angle"))));
+    assert!(args.contains(&("--use-angle", Some("swiftshader"))));
+    assert!(args.contains(&("--enable-unsafe-swiftshader", None)));
+    // Page compositing stays on the CPU exactly as before.
     assert!(args.contains(&("--disable-gpu-compositing", None)));
 }
 
@@ -391,6 +402,13 @@ fn platform_cef_gpu_workarounds_skip_linux_disable_when_force_gpu_set() {
         !args.contains(&("--disable-gpu-compositing", None)),
         "OPENHUMAN_FORCE_GPU=1 must suppress --disable-gpu-compositing, got: {args:?}"
     );
+    // With hardware acceleration opted in, the SwiftShader software-GL fallback
+    // must NOT be forced either — otherwise WebGL would still be stuck on the
+    // software rasteriser despite the override.
+    assert!(
+        !args.contains(&("--use-angle", Some("swiftshader"))),
+        "OPENHUMAN_FORCE_GPU=1 must not force SwiftShader, got: {args:?}"
+    );
 }
 
 #[test]