11 files changed, 197 insertions, 111 deletions

diff --git a/src/controller/callbacks/mouse.c b/src/controller/callbacks/mouse.c
index f901476..34ff290 100644
--- a/src/controller/callbacks/mouse.c
+++ b/src/controller/callbacks/mouse.c
@@ -25,7 +25,7 @@ mouse (int button, int state, int x, int y)
     {
       // Deactive a panning event if one was happening.
       S.pan.active = false;
-
+      
       if (S.selection.active && 
           S.selection.purpose == ZOOM &&
           glutGetModifiers () == GLUT_ACTIVE_CTRL)
@@ -35,14 +35,49 @@ mouse (int button, int state, int x, int y)
            */
           if (x == S.selection.x || y == S.selection.y)
             return;
-
+          
+          /*
+           * Convert the selection boundary from window coordinates to
+           * world coordinates.
+           */
+          glMatrixMode (GL_MODELVIEW);
+          glLoadIdentity ();
+          GLdouble model[16];
+          glGetDoublev (GL_MODELVIEW_MATRIX, model);
+          GLdouble projection[16];
+          glGetDoublev (GL_PROJECTION_MATRIX, projection);
           GLint viewport[4];
           glGetIntegerv (GL_VIEWPORT, viewport);
-
-          zoom (S.selection.x, 
-                viewport[3] - S.selection.y, 
-                x, 
-                viewport[3] - y);
+          
+          check_error (__FILE__, __LINE__);
+          
+          GLdouble start_position[3];
+          gluUnProject (x,
+                        viewport[3] -y,
+                        0,
+                        model,
+                        projection,
+                        viewport,
+                        &start_position[0],
+                        &start_position[1], &start_position[2]);
+          
+          check_error (__FILE__, __LINE__);
+          
+          GLdouble end_position[3];
+          gluUnProject (S.selection.x,
+                        viewport[3] - S.selection.y,
+                        0,
+                        model,
+                        projection,
+                        viewport,
+                        &end_position[0], &end_position[1], &end_position[2]);
+          
+          check_error (__FILE__, __LINE__);
+          
+          zoom (fmin (start_position[0], end_position[0]),
+                fmin (start_position[1], end_position[1]),
+                fmax (start_position[0], end_position[0]),
+                fmax (start_position[1], end_position[1]));
         }
 
       /*