MouseInput: invert y-accel property

Syd Adams:  It could be inverted with nasal for use,
but it feels more natural with positive /forward , negative /
back.

diff --git a/src/Input/FGMouseInput.cxx b/src/Input/FGMouseInput.cxx
index 5d3f7ae2ab3a8722d24a0149fd7336d455e4ec81..b171e021bdac308185d4b1b4c7f8e0e8a4549b23 100644 (file)
--- a/src/Input/FGMouseInput.cxx
+++ b/src/Input/FGMouseInput.cxx
@@ -332,7 +332,7 @@ void FGMouseInput::doMouseMotion (int x, int y)
   }
   if (y != m.y) {
     int delta = y - m.y;
-    yAccelNode->setIntValue( delta );
+    yAccelNode->setIntValue( -delta );
     for (unsigned int i = 0; i < mode.y_bindings[modifiers].size(); i++)
       mode.y_bindings[modifiers][i]->fire(double(delta), double(ysize));
   }