X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FMain%2Fviewer.cxx;h=8dcfb982dbf5f4913eb0c573e2d9e55019293c7d;hb=7cde2e800bccd4883f03eceb5283add24755b377;hp=6a9d99661eaa60de9ad01ed8e839d8067a50a758;hpb=2fa160d41a92b3ca1b574d3cb39dc7a823fc89dd;p=flightgear.git

diff --git a/src/Main/viewer.cxx b/src/Main/viewer.cxx
index 6a9d99661..8dcfb982d 100644
--- a/src/Main/viewer.cxx
+++ b/src/Main/viewer.cxx
@@ -373,25 +373,30 @@ FGViewer::recalcLookFrom ()
   }
 
   // The rotation rotating from the earth centerd frame to
-  // the horizontal local OpenGL frame
-  SGQuatd hlOr = SGQuatd::viewHL(_position);
+  // the horizontal local frame
+  SGQuatd hlOr = SGQuatd::fromLonLat(_position);
 
-  // the rotation from the horizontal local frame to the basic view orientation
+  // The rotation from the horizontal local frame to the basic view orientation
   SGQuatd hlToBody = SGQuatd::fromYawPitchRollDeg(head, pitch, roll);
-  hlToBody = SGQuatd::simToView(hlToBody);
 
-  // The cartesian position of the basic view coordinate
-  SGVec3d position = SGVec3d::fromGeod(_position);
-  // the rotation offset, don't know why heading is negative here ...
-  SGQuatd viewOffsetOr = SGQuatd::simToView(
-    SGQuatd::fromYawPitchRollDeg(-_heading_offset_deg, _pitch_offset_deg,
-                                 _roll_offset_deg));
+  // The rotation offset, don't know why heading is negative here ...
+  mViewOffsetOr
+      = SGQuatd::fromYawPitchRollDeg(-_heading_offset_deg, _pitch_offset_deg,
+                                     _roll_offset_deg);
 
   // Compute the eyepoints orientation and position
   // wrt the earth centered frame - that is global coorinates
   SGQuatd ec2body = hlOr*hlToBody;
-  _absolute_view_pos = position + ec2body.backTransform(_offset_m);
-  mViewOrientation = ec2body*viewOffsetOr;
+
+  // The cartesian position of the basic view coordinate
+  SGVec3d position = SGVec3d::fromGeod(_position);
+
+  // This is rotates the x-forward, y-right, z-down coordinate system the where
+  // simulation runs into the OpenGL camera system with x-right, y-up, z-back.
+  SGQuatd q(-0.5, -0.5, 0.5, 0.5);
+
+  _absolute_view_pos = position + (ec2body*q).backTransform(_offset_m);
+  mViewOrientation = ec2body*mViewOffsetOr*q;
 }
 
 void
@@ -432,7 +437,7 @@ FGViewer::recalcLookAt ()
   SGQuatd geodEyeHlOr = SGQuatd::fromLonLat(_position);
 
   // the rotation offset, don't know why heading is negative here ...
-  SGQuatd eyeOffsetOr =
+  mViewOffsetOr =
     SGQuatd::fromYawPitchRollDeg(-_heading_offset_deg + 180, _pitch_offset_deg,
                                  _roll_offset_deg);
 
@@ -440,7 +445,7 @@ FGViewer::recalcLookAt ()
   SGVec3d eyeOff(-_offset_m.z(), _offset_m.x(), -_offset_m.y());
   SGQuatd ec2eye = geodEyeHlOr*geodEyeOr;
   SGVec3d eyeCart = SGVec3d::fromGeod(_position);
-  eyeCart += (ec2eye*eyeOffsetOr).backTransform(eyeOff);
+  eyeCart += (ec2eye*mViewOffsetOr).backTransform(eyeOff);
 
   SGVec3d atCart = SGVec3d::fromGeod(_target);
 
@@ -459,8 +464,10 @@ FGViewer::recalcLookAt ()
   SGVec3d dir = normalize(atCart - eyeCart);
   // the up directon
   SGVec3d up = ec2eye.backTransform(SGVec3d(0, 0, -1));
-  // rotate dir to the 0-th unit vector
-  // rotate up to 2-th unit vector
+  // rotate -dir to the 2-th unit vector
+  // rotate up to 1-th unit vector
+  // Note that this matches the OpenGL camera coordinate system
+  // with x-right, y-up, z-back.
   mViewOrientation = SGQuatd::fromRotateTo(-dir, 2, up, 1);
 }
 
@@ -652,6 +659,6 @@ FGViewer::update (double dt)
     }
   }
   recalc();
-  _cameraGroup->update(_absolute_view_pos.osg(), mViewOrientation.osg());
+  _cameraGroup->update(toOsg(_absolute_view_pos), toOsg(mViewOrientation));
   _cameraGroup->setCameraParameters(get_v_fov(), get_aspect_ratio());
 }