camera::get_ray() is const

Also changes member variables from public to private.

Resolves #446

Author: hollasch

books/RayTracingInOneWeekend.html

@@ -1320,11 +1320,11 @@
                 origin = point3(0.0, 0.0, 0.0);
             }
 
-            ray get_ray(double u, double v) {
+            ray get_ray(double u, double v) const {
                 return ray(origin, lower_left_corner + u*horizontal + v*vertical - origin);
             }
 
-        public:
+        private:
             point3 origin;
             point3 lower_left_corner;
             vec3 horizontal;
@@ -2577,11 +2577,11 @@
             }
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
 
-            ray get_ray(double u, double v) {
+            ray get_ray(double u, double v) const {
                 return ray(origin, lower_left_corner + u*horizontal + v*vertical - origin);
             }
 
-        public:
+        private:
             point3 origin;
             point3 lower_left_corner;
             vec3 horizontal;
@@ -2668,11 +2668,11 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
             }
 
-            ray get_ray(double s, double t) {
+            ray get_ray(double s, double t) const {
                 return ray(origin, lower_left_corner + s*horizontal + t*vertical - origin);
             }
 
-        public:
+        private:
             point3 origin;
             point3 lower_left_corner;
             vec3 horizontal;
@@ -2806,7 +2806,7 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
             }
 
-            ray get_ray(double s, double t) {
+            ray get_ray(double s, double t) const {
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
                 vec3 rd = lens_radius * random_in_unit_disk();
                 vec3 offset = u * rd.x() + v * rd.y();
@@ -2818,7 +2818,7 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
             }
 
-        public:
+        private:
             point3 origin;
             point3 lower_left_corner;
             vec3 horizontal;

books/RayTracingTheNextWeek.html

@@ -138,7 +138,7 @@
                 vertical = 2*half_height*focus_dist*v;
             }
 
-            ray get_ray(double s, double t) {
+            ray get_ray(double s, double t) const {
                 vec3 rd = lens_radius * random_in_unit_disk();
                 vec3 offset = u * rd.x() + v * rd.y();
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
@@ -150,7 +150,7 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
             }
 
-        public:
+        private:
             point3 origin;
             point3 lower_left_corner;
             vec3 horizontal;

src/common/camera.h

@@ -45,7 +45,7 @@ class camera {
             vertical = 2*half_height*focus_dist*v;
         }
 
-        ray get_ray(double s, double t) {
+        ray get_ray(double s, double t) const {
             vec3 rd = lens_radius * random_in_unit_disk();
             vec3 offset = u * rd.x() + v * rd.y();
             return ray(
@@ -55,7 +55,7 @@ class camera {
             );
         }
 
-    public:
+    private:
         point3 origin;
         point3 lower_left_corner;
         vec3 horizontal;