8 files changed, 19 insertions, 19 deletions
diff --git a/libdimensionxx/camera.cpp b/libdimensionxx/camera.cpp
index 5786055..3536e54 100644
--- a/libdimensionxx/camera.cpp
+++ b/libdimensionxx/camera.cpp
@@ -65,7 +65,7 @@ namespace Dimension
   { }
 
   // Protected copy constructor
-  Camera::Camera(Camera& camera)
+  Camera::Camera(const Camera& camera)
     : m_camera(camera.m_camera)
   { }
 
diff --git a/libdimensionxx/cameras.cpp b/libdimensionxx/cameras.cpp
index 5d84c4f..f9f8302 100644
--- a/libdimensionxx/cameras.cpp
+++ b/libdimensionxx/cameras.cpp
@@ -47,13 +47,13 @@ namespace Dimension
 
   // Shallow-copy this camera
   Camera*
-  Perspective_Camera::copy()
+  Perspective_Camera::copy() const
   {
     return new Perspective_Camera(*this);
   }
 
   // Private copy-constructor, for copy() implementation
-  Perspective_Camera::Perspective_Camera(Perspective_Camera& camera)
+  Perspective_Camera::Perspective_Camera(const Perspective_Camera& camera)
     : Camera(camera)
   { }
 }
diff --git a/libdimensionxx/dimensionxx/camera.hpp b/libdimensionxx/dimensionxx/camera.hpp
index fa13a7e..0f61435 100644
--- a/libdimensionxx/dimensionxx/camera.hpp
+++ b/libdimensionxx/dimensionxx/camera.hpp
@@ -36,7 +36,7 @@ namespace Dimension
     virtual Line ray(const Canvas& canvas, unsigned int x, unsigned int y);
 
     // Shallow-copy a derived camera
-    virtual Camera* copy() = 0;
+    virtual Camera* copy() const = 0;
 
     // Access the wrapped C camera.
     dmnsn_camera*       dmnsn();
@@ -46,7 +46,7 @@ namespace Dimension
     // No-op
     Camera();
     // Shallow-copy
-    Camera(Camera& camera);
+    Camera(const Camera& camera);
     // Wrap an existing camera
     explicit Camera(dmnsn_camera* camera);
 
diff --git a/libdimensionxx/dimensionxx/cameras.hpp b/libdimensionxx/dimensionxx/cameras.hpp
index 364ea4c..ea08535 100644
--- a/libdimensionxx/dimensionxx/cameras.hpp
+++ b/libdimensionxx/dimensionxx/cameras.hpp
@@ -37,11 +37,11 @@ namespace Dimension
     void trans(const Matrix& trans);
 
     // Shallow-copy the camera
-    Camera* copy();
+    Camera* copy() const;
 
   private:
     // Copying prohibited, but used internally
-    Perspective_Camera(Perspective_Camera& camera);
+    Perspective_Camera(const Perspective_Camera& camera);
     Perspective_Camera& operator=(const Perspective_Camera&);
   };
 }
diff --git a/libdimensionxx/dimensionxx/object.hpp b/libdimensionxx/dimensionxx/object.hpp
index 6505162..c661fa8 100644
--- a/libdimensionxx/dimensionxx/object.hpp
+++ b/libdimensionxx/dimensionxx/object.hpp
@@ -41,7 +41,7 @@ namespace Dimension
     virtual bool inside(const Vector& point);
 
     // Shallow-copy a derived object
-    virtual Object* copy() = 0;
+    virtual Object* copy() const = 0;
 
     // Access the wrapped C object
     dmnsn_object*       dmnsn();
@@ -51,7 +51,7 @@ namespace Dimension
     // No-op
     Object();
     // Shallow copy
-    Object(Object& object);
+    Object(const Object& object);
     // Wrap an existing object.
     explicit Object(dmnsn_object* object);
 
diff --git a/libdimensionxx/dimensionxx/objects.hpp b/libdimensionxx/dimensionxx/objects.hpp
index 15c072b..6f7cce0 100644
--- a/libdimensionxx/dimensionxx/objects.hpp
+++ b/libdimensionxx/dimensionxx/objects.hpp
@@ -33,11 +33,11 @@ namespace Dimension
     // ~Sphere();
 
     // Shallow-copy the sphere
-    Object* copy();
+    Object* copy() const;
 
   private:
     // Copying prohibited, but used internally
-    Sphere(Sphere& sphere);
+    Sphere(const Sphere& sphere);
     Sphere& operator=(const Sphere&);
   };
 
@@ -49,11 +49,11 @@ namespace Dimension
     // ~Cube();
 
     // Shallow-copy the cube
-    Object* copy();
+    Object* copy() const;
 
   private:
     // Copying prohibited, but used internally
-    Cube(Cube& cube);
+    Cube(const Cube& cube);
     Cube& operator=(const Cube&);
   };
 }
diff --git a/libdimensionxx/object.cpp b/libdimensionxx/object.cpp
index 9c28e22..407935a 100644
--- a/libdimensionxx/object.cpp
+++ b/libdimensionxx/object.cpp
@@ -86,7 +86,7 @@ namespace Dimension
   { }
 
   // Protected copy constructor
-  Object::Object(Object& object)
+  Object::Object(const Object& object)
     : m_object(object.m_object)
   { }
 
diff --git a/libdimensionxx/objects.cpp b/libdimensionxx/objects.cpp
index 7bedd92..fffa3c4 100644
--- a/libdimensionxx/objects.cpp
+++ b/libdimensionxx/objects.cpp
@@ -33,13 +33,13 @@ namespace Dimension
 
   // Shallow copy a sphere
   Object*
-  Sphere::copy()
+  Sphere::copy() const
   {
     return new Sphere(*this);
   }
 
   // Protected copy constructor
-  Sphere::Sphere(Sphere& sphere)
+  Sphere::Sphere(const Sphere& sphere)
     : Object(sphere)
   { }
 
@@ -54,13 +54,13 @@ namespace Dimension
 
   // Shallow copy a cube
   Object*
-  Cube::copy()
+  Cube::copy() const
   {
     return new Cube(*this);
   }
 
   // Protected copy constructor
-  Cube::Cube(Cube& sphere)
-    : Object(sphere)
+  Cube::Cube(const Cube& cube)
+    : Object(cube)
   { }
 }