Fix T72920: Snap package fails to play audio and blocks audio in other apps

ALSA and OSS are not available for the snap packages, and trying to initialize
them seems to cause some problems for other applications. Instead configure
OpenAL and SDL to use PulseAudio, and set PULSE_SERVER environment variable to
make it work.

release/freedesktop/snap/blender-wrapper

@@ -0,0 +1,19 @@
+# Disable ALSA and OSS as they are not available, and trying to initialize them
+# breaks sound in other apps. Use PulseAudio instead.
+export ALSOFT_DRIVERS=-oss,-alsa,
+export SDL_AUDIODRIVER=pulseaudio
+
+# Make PulseAudio socket available inside the snap-specific $XDG_RUNTIME_DIR
+# This is adapted from https://github.com/ubuntu/snapcraft-desktop-helpers,
+# in common/desktop-exports.
+mkdir -p $XDG_RUNTIME_DIR -m 700
+if [ -n "$XDG_RUNTIME_DIR" ]; then
+    pulsenative="pulse/native"
+    pulseaudio_sockpath="$XDG_RUNTIME_DIR/../$pulsenative"
+    if [ -S "$pulseaudio_sockpath" ]; then
+        export PULSE_SERVER="unix:${pulseaudio_sockpath}"
+    fi
+fi
+
+# Run Blender
+$SNAP/blender

release/freedesktop/snap/snapcraft.yaml.in

@@ -24,7 +24,7 @@ confinement: classic
 
 apps:
     blender:
-        command: ./blender
+        command: ./blender-wrapper
         desktop: ./blender.desktop
 
 version: '@VERSION@'
@@ -46,3 +46,8 @@ parts:
             - libxfixes3
             - libxrender1
             - libxxf86vm1
+    wrapper:
+        plugin: copy
+        source: .
+        files:
+            blender-wrapper: blender-wrapper