Feature Scaling - FlightGear

See also FlightGear and OpenGL ES.

Menu Bar

Hiding the menu bar improves FPS too some degree. More so when FlightGear is running in a window. It can be toggled on/off with [Shift] + [F10] or the Auto Hide option can be used.

GPU Profile

See Graphics card profiles for the main article about this subject.

The following GPU profile was provided by enrogue

<?xml version="1.0"?>

<PropertyList>
  <shaders>
    <custom-settings type="bool">true</custom-settings>
    <clouds type="double">0</clouds>
    <generic type="double">1</generic>
    <landmass type="double">3</landmass>
    <model type="double">0</model>
    <contrails type="double">1</contrails>
    <crop type="double">0</crop>
    <skydome type="bool">false</skydome>
    <transition type="double">0</transition>
    <urban type="double">0</urban>
    <water type="double">3</water>
    <wind-effects type="double">0</wind-effects>
    <vegetation-effects type="double">0</vegetation-effects>
    <forest type="double">0</forest>
    <lights type="double">3</lights>
    <quality-level-internal type="double">3</quality-level-internal>
    <quality-level type="double">-1</quality-level>
  </shaders>
  <random-objects type="bool">true</random-objects>
  <random-vegetation type="bool">true</random-vegetation>
  <random-vegetation-shadows type="bool">false</random-vegetation-shadows>
  <random-vegetation-normals type="bool">false</random-vegetation-normals>
  <vegetation-density type="double">1</vegetation-density>
  <random-buildings type="bool">false</random-buildings>
  <building-density type="double">1</building-density>
  <point-sprites type="bool">true</point-sprites>
  <particles type="bool">true</particles>
  <clouds3d-enable type="bool">true</clouds3d-enable>
  <clouds3d-vis-range type="double">10000</clouds3d-vis-range>
  <clouds3d-detail-range type="double">10000</clouds3d-detail-range>
  <clouds3d-density type="double">0.25</clouds3d-density>
  <shadows>
    <enabled type="bool">true</enabled>
  </shadows>
</PropertyList>

FG1000

See FG1000 for the main article about this subject.

For the time being, the FG1000 must be considered hardly usable on the RPi, i.e. ~200ms/5fps. We're currently in the process of investigating what can be done to make it possible to use the device on the RPi, since that would seem like a perfect use-case.

One thing that's obvious is that initialization of the device takes unusually long. To see what's going on, we can wrap the initialization code inside $FG_ROOT/gui/menubar.xml in between profiling calls:

See also Built-in Profiler.

diff --git a/gui/menubar.xml b/gui/menubar.xml
index ff3faa1ac..6c94b2e76 100644
--- a/gui/menubar.xml
+++ b/gui/menubar.xml
@@ -834,6 +834,7 @@
                        <binding>
                                <command>nasal</command>
                                <script>
+                                       fgcommand("profiler-start");
                                        var nasal_dir = getprop("/sim/fg-root") ~ "/Aircraft/Instruments-3d/FG1000/Nasal/";
                                        if (! defined("fg1000")) {
                                                io.load_nasal(nasal_dir ~ 'FG1000.nas', "fg1000");
@@ -846,6 +847,7 @@
                                        var fg1000system = fg1000.FG1000.getOrCreateInstance();
                                        var pfdindex = fg1000system.addPFD();
                                        fg1000system.displayGUI(pfdindex);
+                                       fgcommand("profiler-stop");
 
                                </script>
                        </binding>

Another thing worth trying is running the built-on OSG optimizer on the root group, this requires patching SG/FG respectively:

diff --git a/simgear/canvas/elements/CanvasGroup.hxx b/simgear/canvas/elements/CanvasGroup.hxx
index 33687637..288da23d 100644
--- a/simgear/canvas/elements/CanvasGroup.hxx
+++ b/simgear/canvas/elements/CanvasGroup.hxx
@@ -20,6 +20,8 @@
 #ifndef CANVAS_GROUP_HXX_
 #define CANVAS_GROUP_HXX_
 
+#include <osgUtil/Optimizer>
+
 #include "CanvasElement.hxx"
 
 #include <list>
@@ -97,6 +99,11 @@ namespace canvas
       osg::BoundingBox
       getTransformedBounds(const osg::Matrix& m) const override;
 
+      void optimize () {
+             osgUtil::Optimizer opt;
+             opt.optimize(_scene_group.get()  );
+      }
+
     protected:
 
       static ElementFactories   _child_factories;

diff --git a/src/Scripting/NasalCanvas.cxx b/src/Scripting/NasalCanvas.cxx
index 602f06989..23aadfb36 100644
--- a/src/Scripting/NasalCanvas.cxx
+++ b/src/Scripting/NasalCanvas.cxx
@@ -521,7 +521,8 @@ naRef initNasalCanvas(naRef globals, naContext c)
     .bases<NasalElement>()
     .method("_createChild", &f_groupCreateChild)
     .method( "_getChild", &f_groupGetChild)
-    .method("_getElementById", &sc::Group::getElementById);
+    .method("_getElementById", &sc::Group::getElementById)
+    .method("optimize", &sc::Group::optimize);
   NasalText::init("canvas.Text")
     .bases<NasalElement>()
     .method("heightForWidth", &sc::Text::heightForWidth)