Fixed fov parameter range for camera_transform.

dlib/geometry/point_transforms.h

@@ -796,7 +796,7 @@ namespace dlib
             *this = camera_transform(vector<double>(1,1,1), 
                                      vector<double>(0,0,0),
                                      vector<double>(0,0,1),
-                                     180,
+                                     90,
                                      1);
         }
 
@@ -808,6 +808,13 @@ namespace dlib
             const unsigned long num_pixels_
         )
         {
+            // make sure requires clause is not broken
+            DLIB_CASSERT(0 < camera_field_of_view_ && camera_field_of_view_ < 180,
+                "\t camera_transform::camera_transform()"
+                << "\n\t Invalid inputs were given to this function."
+                << "\n\t camera_field_of_view_: " << camera_field_of_view_
+                );
+
             camera_pos = camera_pos_;
             camera_looking_at = camera_looking_at_;
             camera_up_direction = camera_up_direction_;

dlib/geometry/point_transforms_abstract.h

@@ -600,7 +600,7 @@ namespace dlib
                 - #get_camera_pos()           == vector<double>(1,1,1) 
                 - #get_camera_looking_at()    == vector<double>(0,0,0) 
                 - #get_camera_up_direction()  == vector<double>(0,0,1) 
-                - #get_camera_field_of_view() == 180 
+                - #get_camera_field_of_view() == 90
                 - #get_num_pixels()           == 1 
         !*/
 
@@ -613,7 +613,7 @@ namespace dlib
         );
         /*!
             requires
-                - 0 < camera_field_of_view < 360
+                - 0 < camera_field_of_view < 180
             ensures
                 - #get_camera_pos() == camera_pos
                 - #get_camera_looking_at() == camera_looking_at