Fixed some bug in the point rotation code and added more unit tests.

dlib/geometry/point_transforms.h

@@ -747,7 +747,7 @@ namespace dlib
 
         matrix<double,3,3> m;
         m = ca,  0, sa,
-             0,  0, 0,
+             0,  1, 0,
             -sa, 0, ca;
 
         vector<double,3> b;
@@ -767,7 +767,7 @@ namespace dlib
         matrix<double,3,3> m;
         m = ca, -sa, 0,
             sa, ca,  0,
-            0,   0,  0;
+            0,   0,  1;
 
         vector<double,3> b;
 

dlib/test/geometry.cpp

@@ -812,17 +812,27 @@ namespace
         const dlib::vector<double> x(1,0,0);
         const dlib::vector<double> y(0,1,0);
         const dlib::vector<double> z(0,0,1);
+        const dlib::vector<double> e(1,1,1);
+        const dlib::vector<double> ex(-1,1,1);
+        const dlib::vector<double> ey(1,-1,1);
+        const dlib::vector<double> ez(1,1,-1);
 
         dlib::vector<double> w;
 
         w = rotate_around_z(pi/2)(x);
         DLIB_TEST(length(w-y) < 1e-12);
+        w = rotate_around_z(pi/2)(e);
+        DLIB_TEST(length(w-ex) < 1e-12);
 
         w = rotate_around_y(-pi/2)(x);
         DLIB_TEST(length(w-z) < 1e-12);
+        w = rotate_around_y(pi/2)(e);
+        DLIB_TEST(length(w-ez) < 1e-12);
 
         w = rotate_around_x(pi/2)(y);
         DLIB_TEST(length(w-z) < 1e-12);
+        w = rotate_around_x(pi/2)(e);
+        DLIB_TEST(length(w-ey) < 1e-12);
 
         w = translate_point(x)(y);
         DLIB_TEST(length(w-x-y) < 1e-12);