switch trackbed value export, erased vehicles sound fix

Track.cpp

@@ -2156,6 +2156,15 @@ TTrack::export_as_text_( std::ostream &Output ) const {
     if( fVerticalRadius != 0.f ) {
         Output << "vradius " << fVerticalRadius << ' ';
     }
+    if( ( eType == tt_Switch )
+     && ( SwitchExtension->m_material3 != null_handle ) ) {
+        auto texturefile { GfxRenderer.Material( m_material2 ).name };
+        if( texturefile.find( szTexturePath ) == 0 ) {
+            // don't include 'textures/' in the path
+            texturefile.erase( 0, std::string{ szTexturePath }.size() );
+        }
+        Output << "trackbed " << texturefile << ' ';
+    }
     // footer
     Output
         << "endtrack"

Track.h

@@ -167,6 +167,7 @@ private:
     float fTexSlope = 0.9f;
 
     glm::dvec3 m_origin;
+    // TODO: store material names as strings, for lossless serialization and export
     material_handle m_material1 = 0; // tekstura szyn albo nawierzchni
     material_handle m_material2 = 0; // tekstura automatycznej podsypki albo pobocza
     using geometryhandle_sequence = std::vector<gfx::geometry_handle>;

sound.cpp

@@ -476,6 +476,13 @@ sound_source::stop( bool const Skipend ) {
 void
 sound_source::update( audio::openal_source &Source ) {
 
+    if( ( m_owner != nullptr )
+     && ( false == m_owner->bEnabled ) ) {
+        // terminate the sound if the owner is gone
+        // TBD, TODO: replace with a listener pattern to receive vehicle removal and cab change events and such?
+        m_stop = true;
+    }
+
     if( sound( sound_id::main ).buffer != null_handle ) {
         // basic variant: single main sound, with optional bookends
         update_basic( Source );