Frederic Bouvier:

I restored the output to cout / cerr
for the options and the warning for the version mismatch.
There is a dummy SG_LOG to allow the windows version to
popup the console.

The snapshot rendering use multipass now.

src/Main/main.cxx

@@ -257,6 +257,12 @@ void fgInitVisuals( void ) {
 
 // For HiRes screen Dumps using Brian Pauls TR Library
 void trRenderFrame( void ) {
+#ifdef FG_ENABLE_MULTIPASS_CLOUDS
+    bool multi_pass_clouds = fgGetBool("/sim/rendering/multi-pass-clouds");
+#else
+    bool multi_pass_clouds = false;
+#endif
+    bool draw_clouds = fgGetBool("/environment/clouds/status");
 
     if ( fgPanelVisible() ) {
         GLfloat height = fgGetInt("/sim/startup/ysize");
@@ -301,14 +307,64 @@ void trRenderFrame( void ) {
     ssgGetLight( 0 ) -> setColour( GL_DIFFUSE, white );
     thesky->preDraw( cur_fdm_state->get_Altitude() * SG_FEET_TO_METER,
                      fog_exp2_density );
-    thesky->drawUpperClouds();
 
     // draw the ssg scene
     // return to the desired diffuse color
     ssgGetLight( 0 ) -> setColour( GL_DIFFUSE, l->scene_diffuse() );
     glEnable( GL_DEPTH_TEST );
     ssgSetNearFar( scene_nearplane, scene_farplane );
-    ssgCullAndDraw( globals->get_scenery()->get_scene_graph() );
+    if ( draw_clouds ) {
+        // Draw the terrain
+        FGTileMgr::set_tile_filter( true );
+        sgSetModelFilter( false );
+        globals->get_aircraft_model()->select( false );
+        ssgCullAndDraw( globals->get_scenery()->get_scene_graph() );
+        // Disable depth buffer update, draw the clouds
+        glDepthMask( GL_FALSE );
+        thesky->drawUpperClouds();
+        if ( multi_pass_clouds ) {
+            thesky->drawLowerClouds();
+        }
+        glDepthMask( GL_TRUE );
+        if ( multi_pass_clouds ) {
+            // Draw the objects except the aircraft
+            //  and update the stencil buffer with 1
+            glEnable( GL_STENCIL_TEST );
+            glStencilFunc( GL_ALWAYS, 1, 1 );
+            glStencilOp( GL_REPLACE, GL_REPLACE, GL_REPLACE );
+        }
+        FGTileMgr::set_tile_filter( false );
+        sgSetModelFilter( true );
+        ssgCullAndDraw( globals->get_scenery()->get_scene_graph() );
+        if ( multi_pass_clouds ) {
+            // Disable depth buffer update, draw the clouds where the
+            //  objects overwrite the already drawn clouds, by testing
+            //  the stencil buffer against 1
+            glDepthMask( GL_FALSE );
+            glStencilFunc( GL_EQUAL, 1, 1 );
+            glStencilOp( GL_KEEP, GL_KEEP, GL_KEEP );
+            thesky->drawUpperClouds();
+            thesky->drawLowerClouds();
+            glDepthMask( GL_TRUE );
+            glDisable( GL_STENCIL_TEST );
+        } else {
+            glDepthMask( GL_FALSE );
+            thesky->drawLowerClouds();
+            glDepthMask( GL_TRUE );
+        }
+
+        // Draw the aircraft
+        sgSetModelFilter( false );
+        globals->get_aircraft_model()->select( true );
+        ssgCullAndDraw( globals->get_scenery()->get_scene_graph() );
+        FGTileMgr::set_tile_filter( true );
+        sgSetModelFilter( true );
+    } else {
+        FGTileMgr::set_tile_filter( true );
+        sgSetModelFilter( true );
+        globals->get_aircraft_model()->select( true );
+        ssgCullAndDraw( globals->get_scenery()->get_scene_graph() );
+    }
 
     // draw the lights
     glFogf (GL_FOG_DENSITY, rwy_exp2_punch_through);
@@ -1431,12 +1487,13 @@ bool fgMainInit( int argc, char **argv ) {
     if ( !(base_version == required_version) ) {
         // tell the operator how to use this application
 
-        SG_LOG( SG_GENERAL, SG_ALERT, endl << "Base package check failed ... " \
+        SG_LOG( SG_GENERAL, SG_ALERT, "" ); // To popup the console on windows
+        cerr << endl << "Base package check failed ... " \
              << "Found version " << base_version << " at: " \
-             << globals->get_fg_root() );
+             << globals->get_fg_root() << endl;
-        SG_LOG( SG_GENERAL, SG_ALERT, "Please upgrade to version: " << required_version );
+        cerr << "Please upgrade to version: " << required_version << endl;
 #ifdef _MSC_VER
-        SG_LOG( SG_GENERAL, SG_ALERT, "Hit a key to continue..." );
+        cerr << "Hit a key to continue..." << endl;
         cin.get();
 #endif
         exit(-1);
@@ -1472,6 +1529,7 @@ bool fgMainInit( int argc, char **argv ) {
 #endif
 
     // Clouds3D requires an alpha channel
+    // clouds may require stencil buffer
     fgOSOpenWindow( fgGetInt("/sim/startup/xsize"),
                     fgGetInt("/sim/startup/ysize"),
                     fgGetInt("/sim/rendering/bits-per-pixel"),

src/Main/options.cxx

@@ -1566,6 +1566,7 @@ fgUsage (bool verbose)
 
     SGPropertyNode options_root;
 
+    SG_LOG( SG_GENERAL, SG_ALERT, "" ); // To popup the console on Windows
     cout << endl;
 
     try {
@@ -1686,6 +1687,10 @@ fgUsage (bool verbose)
         cout << endl;
         cout << "For a complete list of options use --help --verbose" << endl;
     }
+#ifdef _MSC_VER
+    cout << "Hit a key to continue..." << endl;
+    cin.get();
+#endif
 }
 
 static void fgSearchAircraft(const SGPath &path, string_list &aircraft,
@@ -1762,12 +1767,13 @@ void fgShowAircraft(const SGPath &path, bool recursive) {
     fgSearchAircraft( path, aircraft, recursive );
 
     sort(aircraft.begin(), aircraft.end());
-    SG_LOG( SG_GENERAL, SG_ALERT, "Available aircraft:" );
+    SG_LOG( SG_GENERAL, SG_ALERT, "" ); // To popup the console on Windows
+    cout << "Available aircraft:" << endl;
     for ( unsigned int i = 0; i < aircraft.size(); i++ ) {
-        SG_LOG( SG_GENERAL, SG_ALERT, aircraft[i] );
+        cout << aircraft[i] << endl;
     }
 #ifdef _MSC_VER
-    SG_LOG( SG_GENERAL, SG_ALERT, "Hit a key to continue..." );
+    cout << "Hit a key to continue..." << endl;
     cin.get();
 #endif
 }