X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FInstrumentation%2Faltimeter.cxx;h=0f8d5fc2c7a1ab184c0f790eccf3205c78b0e754;hb=3a11f8ae2843c1f3629f4168e5b10c3993c7bd3e;hp=2a9578705ce73b54cc8a7aad7668278972e320fc;hpb=0a6d2b75591fa02fb38457b583790fb8c4fa22a2;p=flightgear.git

diff --git a/src/Instrumentation/altimeter.cxx b/src/Instrumentation/altimeter.cxx
index 2a9578705..0f8d5fc2c 100644
--- a/src/Instrumentation/altimeter.cxx
+++ b/src/Instrumentation/altimeter.cxx
@@ -1,90 +1,82 @@
 // altimeter.cxx - an altimeter tied to the static port.
 // Written by David Megginson, started 2002.
+// Modified by John Denker in 2007 to use a two layer atmosphere
+// model in src/Environment/atmosphere.?xx
 //
 // This file is in the Public Domain and comes with no warranty.
 
+// Example invocation, in the instrumentation.xml file:
+//      <altimeter>
+//        <name>encoder</name>
+//        <number>0</number>
+//        <static-pressure>/systems/static/pressure-inhg</static-pressure>
+//        <quantum>10</quantum>
+//        <tau>0</tau>
+//      </altimeter>
+// Note non-default name, quantum, and tau values.
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
 #include <simgear/math/interpolater.hxx>
+#include <simgear/math/SGMath.hxx>
 
-#include "altimeter.hxx"
 #include <Main/fg_props.hxx>
 #include <Main/util.hxx>
+#include <Environment/atmosphere.hxx>
 
+#include "altimeter.hxx"
 
-// A higher number means more responsive
-#define RESPONSIVENESS 10.0
-
-
-// Altitude based on pressure difference from sea level.
-// pressure difference inHG, altitude ft
-static double altitude_data[][2] = {
- { -8.41, -8858.27 },
- { 0.00, 0.00 },
- { 3.05, 2952.76 },
- { 5.86, 5905.51 },
- { 8.41, 8858.27 },
- { 10.74, 11811.02 },
- { 12.87, 14763.78 },
- { 14.78, 17716.54 },
- { 16.55, 20669.29 },
- { 18.13, 23622.05 },
- { 19.62, 26574.80 },
- { 20.82, 29527.56 },
- { 21.96, 32480.31 },
- { 23.01, 35433.07 },
- { 23.91, 38385.83 },
- { 24.71, 41338.58 },
- { 25.40, 44291.34 },
- { 26.00, 47244.09 },
- { 26.51, 50196.85 },
- { 26.96, 53149.61 },
- { 27.35, 56102.36 },
- { 27.68, 59055.12 },
- { 27.98, 62007.87 },
- { 29.62, 100000.00 },            // just to fill it in
- { -1, -1 }
-};
-
-
-Altimeter::Altimeter ()
-    : _altitude_table(new SGInterpTable)
-{
-
-    for (int i = 0; altitude_data[i][0] != -1; i++)
-        _altitude_table->addEntry(altitude_data[i][0], altitude_data[i][1]);
-}
+Altimeter::Altimeter ( SGPropertyNode *node, double quantum )
+    : _name(node->getStringValue("name", "altimeter")),
+      _num(node->getIntValue("number", 0)),
+      _static_pressure(node->getStringValue("static-pressure", "/systems/static/pressure-inhg")),
+      _tau(node->getDoubleValue("tau", 0.1)),
+      _quantum(node->getDoubleValue("quantum", quantum))
+{}
 
 Altimeter::~Altimeter ()
-{
-    delete _altitude_table;
-}
+{}
 
 void
 Altimeter::init ()
 {
-    _serviceable_node =
-        fgGetNode("/instrumentation/altimeter/serviceable", true);
-    _setting_node =
-        fgGetNode("/instrumentation/altimeter/setting-inhg", true);
-    _pressure_node =
-        fgGetNode("/systems/static/pressure-inhg", true);
-    _altitude_node =
-        fgGetNode("/instrumentation/altimeter/indicated-altitude-ft", true);
+    string branch;
+    branch = "/instrumentation/" + _name;
+
+    SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
+    raw_PA = 0.0;
+    _kollsman = 0.0;
+    _pressure_node     = fgGetNode(_static_pressure.c_str(), true);
+    _serviceable_node  = node->getChild("serviceable", 0, true);
+    _setting_node      = node->getChild("setting-inhg", 0, true);
+    _press_alt_node    = node->getChild("pressure-alt-ft", 0, true);
+    _mode_c_node       = node->getChild("mode-c-alt-ft", 0, true);
+    _altitude_node     = node->getChild("indicated-altitude-ft", 0, true);
+
+    if (_setting_node->getDoubleValue() == 0)
+        _setting_node->setDoubleValue(29.921260);
 }
 
 void
 Altimeter::update (double dt)
 {
     if (_serviceable_node->getBoolValue()) {
+        double trat = _tau > 0 ? dt/_tau : 100;
         double pressure = _pressure_node->getDoubleValue();
         double setting = _setting_node->getDoubleValue();
-
-                                // Move towards the current setting
-        double last_altitude = _altitude_node->getDoubleValue();
-        double current_altitude =
-            _altitude_table->interpolate(setting - pressure);
-        _altitude_node->setDoubleValue(fgGetLowPass(last_altitude,
-                                                    current_altitude,
-                                                    dt * RESPONSIVENESS));
+        double press_alt = _press_alt_node->getDoubleValue();
+        // The mechanism settles slowly toward new pressure altitude:
+        raw_PA = fgGetLowPass(raw_PA, _altimeter.press_alt_ft(pressure), trat);
+        _mode_c_node->setDoubleValue(100 * SGMiscd::round(raw_PA/100));
+        _kollsman = fgGetLowPass(_kollsman, _altimeter.kollsman_ft(setting), trat);
+        if (_quantum)
+            press_alt = _quantum * SGMiscd::round(raw_PA/_quantum);
+        else
+            press_alt = raw_PA;
+        _press_alt_node->setDoubleValue(press_alt);
+        _altitude_node->setDoubleValue(press_alt - _kollsman);
     }
 }