Started support for animations. Currently, the only supported type

(other than "none") is "spin", which must be tied to a property giving
a value in RPM.  This gets the DC-3 propellers turning.  The next type
will be "rotation", which will allow the flaps, elevators, ailerons,
and rudders to move (and even gear, eventually).  Later, I'll add
"shift" for sliding things around, and will figure something out for
blinking lights.

src/Main/model.cxx

@@ -47,10 +47,9 @@ find_named_node (ssgEntity * node, const string &name)
 
 FGAircraftModel::FGAircraftModel ()
   : _props(new SGPropertyNode),
-    _object(0),
+    _model(0),
     _selector(new ssgSelector),
-    _position(new ssgTransform),
-    _prop_position(0)
+    _position(new ssgTransform)
 {
 }
 
@@ -67,6 +66,8 @@ FGAircraftModel::init ()
   // TODO: optionally load an XML file with a pointer to the 3D object
   // and placement and animation info
 
+  SG_LOG(SG_INPUT, SG_INFO, "Initializing aircraft 3D model");
+
 				// Load the 3D aircraft object itself
   SGPath path = globals->get_fg_root();
   path.append(fgGetString("/sim/model/path", "Models/Geometry/glider.ac"));
@@ -83,28 +84,23 @@ FGAircraftModel::init ()
   }
 
   ssgTexturePath((char *)path.dir().c_str());
-  _object = ssgLoad((char *)path.c_str());
-  if (_object == 0) {
-    _object = ssgLoad((char *)"Models/Geometry/glider.ac");
-    if (_object == 0)
+  _model = ssgLoad((char *)path.c_str());
+  if (_model == 0) {
+    _model = ssgLoad((char *)"Models/Geometry/glider.ac");
+    if (_model == 0)
       throw sg_exception("Failed to load an aircraft model");
   }
 
-				// Find the propeller
-  ssgEntity * prop_node = find_named_node(_object, "Propeller");
-  if (prop_node != 0) {
-    _prop_position = new ssgTransform;
-    int nParents = prop_node->getNumParents();
-    _prop_position->addKid(prop_node);
-    for (int i = 0; i < nParents; i++) {
-      ssgBranch * parent = prop_node->getParent(i);
-      parent->replaceKid(prop_node, _prop_position);
-    }
+				// Load animations
+  vector<SGPropertyNode *> animation_nodes =
+    _props->getChildren("animation");
+  for (int i = 0; i < animation_nodes.size(); i++) {
+    _animations.push_back(read_animation(animation_nodes[i]));
   }
 
 				// Set up the alignment node
   ssgTransform * align = new ssgTransform;
-  align->addKid(_object);
+  align->addKid(_model);
   sgMat4 rot_matrix;
   sgMat4 off_matrix;
   sgMat4 res_matrix;
@@ -141,23 +137,16 @@ FGAircraftModel::unbind ()
 void
 FGAircraftModel::update (int dt)
 {
-  // START TEMPORARY KLUDGE
-  static float prop_rotation = 0;
-  static sgMat4 prop_matrix;
-
   _current_timestamp.stamp();
-  long ms = (_current_timestamp - _last_timestamp) / 1000;
+  long elapsed_ms = (_current_timestamp - _last_timestamp) / 1000;
   _last_timestamp.stamp();
 
-  double rpms = fgGetDouble("/engines/engine[0]/rpm") / 60000.0;
-  prop_rotation += (ms * rpms * 360);
-  while (prop_rotation >= 360)
-    prop_rotation -= 360;
-  // END TEMPORARY KLUDGE
-
   if (globals->get_viewmgr()->get_current() == 0) {
     _selector->select(false);
   } else {
+    for (int i = 0; i < _animations.size(); i++)
+      do_animation(_animations[i], elapsed_ms);
+
     _selector->select(true);
     FGViewerRPH *pilot_view =
       (FGViewerRPH *)globals->get_viewmgr()->get_view( 0 );
@@ -179,19 +168,88 @@ FGAircraftModel::update (int dt)
     sgCoord tuxpos;
     sgSetCoord( &tuxpos, sgTUX );
     _position->setTransform( &tuxpos );
+  }
 
-    // START TEMPORARY KLUDGE
-    if (_prop_position != 0) {
-      double offset = -.75;
-      sgMat4 tmp;
-      sgMakeTransMat4(prop_matrix, 0, 0, offset);
-      sgMakeRotMat4(tmp, 0, 0, prop_rotation);
-      sgPostMultMat4(prop_matrix, tmp);
-      sgMakeTransMat4(tmp, 0, 0, -offset);
-      sgPostMultMat4(prop_matrix, tmp);
-      _prop_position->setTransform(prop_matrix);
-    }
-    // END_TEMPORARY KLUDGE
+}
+
+FGAircraftModel::Animation
+FGAircraftModel::read_animation (const SGPropertyNode * node)
+{
+  Animation animation;
+
+				// Figure out the animation type
+  string type_name = node->getStringValue("type");
+  if (type_name == "spin") {
+    SG_LOG(SG_INPUT, SG_INFO, "Reading spin animation");
+    animation.type = Animation::Spin;
+  } else {
+    animation.type = Animation::None;
+    SG_LOG(SG_INPUT, SG_ALERT, "Unknown animation type " << type_name);
+    return animation;
+  }
+
+				// Find the object to be animated
+  string object_name = node->getStringValue("object-name");
+  ssgEntity * target = find_named_node(_model, object_name);
+  if (target != 0) {
+    SG_LOG(SG_INPUT, SG_INFO, "  Target object is " << object_name);
+  } else {
+    animation.type = Animation::None;
+    SG_LOG(SG_INPUT, SG_ALERT, "Object " << object_name
+	   << " not found in model");
+    return animation;
+  }
+
+				// Splice a transform node into the tree
+  animation.transform = new ssgTransform;
+  int nParents = target->getNumParents();
+  animation.transform->addKid(target);
+  for (int i = 0; i < nParents; i++) {
+    ssgBranch * parent = target->getParent(i);
+    parent->replaceKid(target, animation.transform);
+  }
+
+				// Get the node
+  animation.prop =
+    fgGetNode(node->getStringValue("property", "/null"), true);
+
+				// Get the center and axis
+  animation.center_x = node->getFloatValue("center/x-m", 0);
+  animation.center_y = node->getFloatValue("center/y-m", 0);
+  animation.center_z = node->getFloatValue("center/z-m", 0);
+  animation.axis_x = node->getFloatValue("axis/x", 0);
+  animation.axis_y = node->getFloatValue("axis/y", 1);
+  animation.axis_z = node->getFloatValue("axis/z", 0);
+
+  return animation;
+}
+
+void
+FGAircraftModel::do_animation (Animation &animation, long elapsed_ms)
+{
+  switch (animation.type) {
+  case Animation::None:
+    return;
+  case Animation::Spin: {
+    float velocity_rpms = animation.prop->getDoubleValue() / 60000.0;
+    animation.position += (elapsed_ms * velocity_rpms * 360);
+    while (animation.position >= 360)
+      animation.position -= 360;
+    sgMakeTransMat4(animation.matrix, -animation.center_x,
+		    -animation.center_y, -animation.center_z);
+    sgVec3 axis;
+    sgSetVec3(axis, animation.axis_x, animation.axis_y, animation.axis_z);
+    sgMat4 tmp;
+    sgMakeRotMat4(tmp, animation.position, axis);
+    sgPostMultMat4(animation.matrix, tmp);
+    sgMakeTransMat4(tmp, animation.center_x,
+		    animation.center_y, animation.center_z);
+    sgPostMultMat4(animation.matrix, tmp);
+    animation.transform->setTransform(animation.matrix);
+    return;
+  }
+  default:
+    return;
   }
 }
 

src/Main/model.hxx

@@ -10,6 +10,12 @@
 # error This library requires C++
 #endif
 
+#include <string>
+#include <vector>
+
+SG_USING_STD(string);
+SG_USING_STD(vector);
+
 #include "fgfs.hxx"
 #include <simgear/misc/props.hxx>
 #include <simgear/timing/timestamp.hxx>
@@ -28,15 +34,38 @@ public:
 
 private:
 
+  struct Animation
+  {
+    enum Type {
+      None,
+      Spin
+    };
+    string name;
+    Type type;
+    ssgTransform * transform;
+    sgMat4 matrix;
+    SGPropertyNode * prop;
+    float position;
+    float center_x;
+    float center_y;
+    float center_z;
+    float axis_x;
+    float axis_y;
+    float axis_z;
+  };
+
+  Animation read_animation (const SGPropertyNode * node);
+  void do_animation (Animation &animation, long elapsed_ms);
+
   SGPropertyNode * _props;
-  ssgEntity * _object;
+  ssgEntity * _model;
   ssgSelector * _selector;
   ssgTransform * _position;
 
   SGTimeStamp _last_timestamp;
   SGTimeStamp _current_timestamp;
 
-  ssgTransform * _prop_position;
+  vector<Animation> _animations;
 
 };