X-Git-Url: https://gerrit.simantics.org/r/gitweb?a=blobdiff_plain;f=org.simantics.g3d.vtk%2Fsrc%2Forg%2Fsimantics%2Fg3d%2Fvtk%2Fswt%2FvtkCameraAndSelectorAction.java;h=7a0cc0314d228a793e73ce3b2c49fe6c70e425da;hb=refs%2Fchanges%2F54%2F3954%2F1;hp=ebdfb245219a43990271074a2d8f253ffdf774cf;hpb=4ff29034895671ae5375c85bdb86184e06396844;p=simantics%2F3d.git

diff --git a/org.simantics.g3d.vtk/src/org/simantics/g3d/vtk/swt/vtkCameraAndSelectorAction.java b/org.simantics.g3d.vtk/src/org/simantics/g3d/vtk/swt/vtkCameraAndSelectorAction.java
index ebdfb245..7a0cc031 100644
--- a/org.simantics.g3d.vtk/src/org/simantics/g3d/vtk/swt/vtkCameraAndSelectorAction.java
+++ b/org.simantics.g3d.vtk/src/org/simantics/g3d/vtk/swt/vtkCameraAndSelectorAction.java
@@ -118,10 +118,10 @@ public class vtkCameraAndSelectorAction extends vtkSwtAction implements ISelecti
 		int y = e.getY();
 		// rotate
 		if (this.InteractionMode == 1) {
-			cam.Azimuth(lastX - x);
-			cam.Elevation(y - lastY);
+			cam.Elevation(clampElevationDelta(y - lastY));
 			if (doNotRotate)
 				cam.SetViewUp(upDirection);
+			cam.Azimuth(lastX - x);
 			cam.OrthogonalizeViewUp();
 			resetCameraClippingRange();
 			// panel.UpdateLight();
@@ -184,6 +184,25 @@ public class vtkCameraAndSelectorAction extends vtkSwtAction implements ISelecti
 		return true;
 	}
 
+	private static double dot(double[] a, double[] b) {
+		return a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
+	}
+	
+	/** Calculate change in elevation, clamped to vertical directions. */
+	private double clampElevationDelta(double elevationDelta) {
+		if (!doNotRotate)
+			return elevationDelta;
+		
+		double[] direction = cam.GetDirectionOfProjection();
+		double d = Math.min(1.0,  Math.max(-1.0, dot(direction, upDirection)));
+		double elevation = Math.toDegrees(Math.acos(d)) + elevationDelta;
+		if (elevation < 0)
+			elevationDelta -= elevation - 1e-5;
+		else if (elevation > 180)
+			elevationDelta -= elevation - 180 + 1e-5;
+		return elevationDelta;
+	}
+
 	@Override
 	public boolean mouseWheelMoved(MouseWheelEvent e) {
 		double zoomFactor;