Comments and style adjustments, and a couple fixes.

15 files changed, 40 insertions, 20 deletions

diff --git a/libdimensionxx/camera.cpp b/libdimensionxx/camera.cpp
index ba2428a..efe0802 100644
--- a/libdimensionxx/camera.cpp
+++ b/libdimensionxx/camera.cpp
@@ -30,7 +30,7 @@ namespace Dimension
   Line
   Camera::ray(const Canvas& canvas, unsigned int x, unsigned int y)
   {
-    return Line(dmnsn()->ray_fn(dmnsn(), canvas.dmnsn(), x, y));
+    return Line((*dmnsn()->ray_fn)(dmnsn(), canvas.dmnsn(), x, y));
   }
 
   // Return the wrapped camera
@@ -74,7 +74,7 @@ namespace Dimension
   bool
   Camera::unique() const
   {
-    return m_camera.unique();
+    return m_camera && m_camera.unique();
   }
 
   // Set the wrapped dmnsn_camera*
diff --git a/libdimensionxx/cameras.cpp b/libdimensionxx/cameras.cpp
index ea0bca9..dee4df6 100644
--- a/libdimensionxx/cameras.cpp
+++ b/libdimensionxx/cameras.cpp
@@ -31,7 +31,7 @@ namespace Dimension
     }
   }
 
-  // Delete a perspective camera
+  // Delete a perspective camera, if we're the last reference
   Perspective_Camera::~Perspective_Camera()
   {
     if (unique()) {
@@ -39,24 +39,28 @@ namespace Dimension
     }
   }
 
+  // Get the transformation matrix
   Matrix
   Perspective_Camera::trans()
   {
     return Matrix(dmnsn_get_perspective_camera_trans(dmnsn()));
   }
 
+  // Set the transformation matrix
   void
   Perspective_Camera::trans(const Matrix& trans)
   {
     dmnsn_set_perspective_camera_trans(dmnsn(), trans.dmnsn());
   }
 
+  // Shallow-copy this camera
   Camera*
   Perspective_Camera::copy() const
   {
     return new Perspective_Camera(*this);
   }
 
+  // Private copy-constructor, for copy() implementation
   Perspective_Camera::Perspective_Camera(const Perspective_Camera& camera)
     : Camera(camera)
   { }
diff --git a/libdimensionxx/canvas.cpp b/libdimensionxx/canvas.cpp
index 3ff9d32..6118730 100644
--- a/libdimensionxx/canvas.cpp
+++ b/libdimensionxx/canvas.cpp
@@ -24,7 +24,12 @@ namespace Dimension
 {
   // Allocate the canvas with dmnsn_new_canvas()
   Canvas::Canvas(unsigned int width, unsigned int height)
-    : m_canvas(new dmnsn_canvas*(dmnsn_new_canvas(width, height))) { }
+    : m_canvas(new dmnsn_canvas*(dmnsn_new_canvas(width, height)))
+  {
+    if (!dmnsn()) {
+      throw Dimension_Error("Couldn't allocate canvas.");
+    }
+  }
 
   // Wrap an existing dmnsn_canvas*
   Canvas::Canvas(dmnsn_canvas* canvas)
diff --git a/libdimensionxx/cookie-fopencookie.cpp b/libdimensionxx/cookie-fopencookie.cpp
index e165c8d..1d1f813 100644
--- a/libdimensionxx/cookie-fopencookie.cpp
+++ b/libdimensionxx/cookie-fopencookie.cpp
@@ -26,12 +26,11 @@
 #endif
 #include <stdio.h>
 
-// The conundrum: libdimension and libdimension-* use C I/O, with FILE*'s.
-// We want to use C++ I/O with std::i/ostreams. If present, we use the
-// nonportable GNU stdio extension fopencookie(), which creates a FILE* with
-// custom read/write/seek functions.  BSD also has a similar function, funopen()
-// which we should use too.  Failing in all that, fall back on a tmpfile()
-// buffer (see cookie-tmpfile.cpp).
+// The conundrum: libdimension uses C I/O, with FILE*'s. We want to use C++ I/O
+// with std::i/ostreams. If present, we use the nonportable GNU stdio extension
+// fopencookie(), which creates a FILE* with custom read/write/seek functions.
+// BSD also has a similar function, funopen() which we should use too.  Failing
+// in all that, fall back on a tmpfile() buffer (see cookie-tmpfile.cpp).
 
 namespace Dimension
 {
diff --git a/libdimensionxx/cookie-tmpfile.cpp b/libdimensionxx/cookie-tmpfile.cpp
index 6a41f09..b2d25b8 100644
--- a/libdimensionxx/cookie-tmpfile.cpp
+++ b/libdimensionxx/cookie-tmpfile.cpp
@@ -21,7 +21,7 @@
 #include "dimensionxx.hpp"
 #include <stdio.h>
 
-// Use a tmpfile as a buffer for a C++/C I/O interface.
+// Use a tmpfile() as a buffer for a C++/C I/O interface.
 
 namespace Dimension
 {
diff --git a/libdimensionxx/dimensionxx/cameras.hpp b/libdimensionxx/dimensionxx/cameras.hpp
index cabae97..2726a0c 100644
--- a/libdimensionxx/dimensionxx/cameras.hpp
+++ b/libdimensionxx/dimensionxx/cameras.hpp
@@ -32,9 +32,11 @@ namespace Dimension
     Perspective_Camera(const Matrix& trans);
     ~Perspective_Camera();
 
+    // Get/set the transformation matrix
     Matrix trans();
     void trans(const Matrix& trans);
 
+    // Shallow-copy the camera
     Camera* copy() const;
 
   private:
diff --git a/libdimensionxx/dimensionxx/cookie.hpp b/libdimensionxx/dimensionxx/cookie.hpp
index 0d8b4da..9dbe7b8 100644
--- a/libdimensionxx/dimensionxx/cookie.hpp
+++ b/libdimensionxx/dimensionxx/cookie.hpp
@@ -38,12 +38,15 @@ namespace Dimension
     FILE_Cookie(std::iostream& iostr);
     ~FILE_Cookie();
 
+    // Get the magic FILE*
     FILE*       file();
     const FILE* file() const;
 
+    // Are we an input or output stream?
     bool is_input() const;
     bool is_output() const;
 
+    // Get the C++ streams
     std::istream&       istr();
     const std::istream& istr() const;
     std::ostream&       ostr();
diff --git a/libdimensionxx/dimensionxx/error.hpp b/libdimensionxx/dimensionxx/error.hpp
index 7fb0e53..ad61284 100644
--- a/libdimensionxx/dimensionxx/error.hpp
+++ b/libdimensionxx/dimensionxx/error.hpp
@@ -20,8 +20,8 @@
 
 // Wrappers for libdimension error handling, and an exception class.
 // dmnsn_error is still used by libdimensionxx whenever an exception shouldn't
-// be thrown, like in destructors, and whenever libdimension or libdimension-*
-// use it internally.  Exceptions are thrown otherwise to report errors.
+// be thrown, like in destructors, and whenever libdimension uses it internally.
+// Exceptions are thrown otherwise to report errors.
 
 #ifndef DIMENSIONXX_ERROR_HPP
 #define DIMENSIONXX_ERROR_HPP
diff --git a/libdimensionxx/dimensionxx/object.hpp b/libdimensionxx/dimensionxx/object.hpp
index c56d358..e0b45f4 100644
--- a/libdimensionxx/dimensionxx/object.hpp
+++ b/libdimensionxx/dimensionxx/object.hpp
@@ -40,10 +40,10 @@ namespace Dimension
     virtual Array<double> intersections(const Line& l);
     virtual bool inside(const Vector& point);
 
-    // Shallow-copy a derived
+    // Shallow-copy a derived object
     virtual Object* copy() const = 0;
 
-    // Access the wrapped C object.
+    // Access the wrapped C object
     dmnsn_object*       dmnsn();
     const dmnsn_object* dmnsn() const;
 
diff --git a/libdimensionxx/dimensionxx/objects.hpp b/libdimensionxx/dimensionxx/objects.hpp
index 5b43dc4..11e408c 100644
--- a/libdimensionxx/dimensionxx/objects.hpp
+++ b/libdimensionxx/dimensionxx/objects.hpp
@@ -32,6 +32,7 @@ namespace Dimension
     Sphere();
     ~Sphere();
 
+    // Shallow-copy the sphere
     Object* copy() const;
 
   private:
@@ -47,6 +48,7 @@ namespace Dimension
     Cube();
     ~Cube();
 
+    // Shallow-copy the cube
     Object* copy() const;
 
   private:
diff --git a/libdimensionxx/dimensionxx/raytrace.hpp b/libdimensionxx/dimensionxx/raytrace.hpp
index bfd7e1c..8cf4ee4 100644
--- a/libdimensionxx/dimensionxx/raytrace.hpp
+++ b/libdimensionxx/dimensionxx/raytrace.hpp
@@ -34,6 +34,7 @@ namespace Dimension
     Raytracer(Scene& scene);
     ~Raytracer();
 
+    // Render the scene
     void render();
     Progress render_async();
 
diff --git a/libdimensionxx/object.cpp b/libdimensionxx/object.cpp
index 61b8b7d..1a43f62 100644
--- a/libdimensionxx/object.cpp
+++ b/libdimensionxx/object.cpp
@@ -26,12 +26,14 @@ namespace Dimension
   Object::~Object()
   { }
 
+  // Get the transformation matrix
   Matrix
   Object::trans()
   {
     return Matrix(dmnsn()->trans);
   }
 
+  // Set the transformation matrix
   void
   Object::trans(const Matrix& trans)
   {
@@ -42,14 +44,14 @@ namespace Dimension
   Array<double>
   Object::intersections(const Line& l)
   {
-    return Array<double>(dmnsn()->intersections_fn(dmnsn(), l.dmnsn()));
+    return Array<double>((*dmnsn()->intersections_fn)(dmnsn(), l.dmnsn()));
   }
 
   // Whether the point `point' is inside the object
   bool
   Object::inside(const Vector& point)
   {
-    return dmnsn()->inside_fn(dmnsn(), point.dmnsn());
+    return (*dmnsn()->inside_fn)(dmnsn(), point.dmnsn());
   }
 
   // Return the wrapped object
@@ -93,7 +95,7 @@ namespace Dimension
   bool
   Object::unique() const
   {
-    return m_object.unique();
+    return m_object && m_object.unique();
   }
 
   // Set the wrapped dmnsn_object*
diff --git a/libdimensionxx/progress.cpp b/libdimensionxx/progress.cpp
index 66d9d7f..7cf42aa 100644
--- a/libdimensionxx/progress.cpp
+++ b/libdimensionxx/progress.cpp
@@ -22,6 +22,7 @@
 
 namespace Dimension
 {
+  // No-op virtual destructor
   Persist_Base::~Persist_Base()
   { }
 
@@ -38,7 +39,7 @@ namespace Dimension
   // Finish the progress if not yet finished and we are unique
   Progress::~Progress()
   {
-    if (m_progress) {
+    if (m_progress && m_progress.unique()) {
       try {
         finish();
       } catch (...) {
diff --git a/libdimensionxx/raytrace.cpp b/libdimensionxx/raytrace.cpp
index 263fe6d..d3ae769 100644
--- a/libdimensionxx/raytrace.cpp
+++ b/libdimensionxx/raytrace.cpp
@@ -22,6 +22,7 @@
 
 namespace Dimension
 {
+  // Construct a raytracer
   Raytracer::Raytracer(Scene& scene)
     : m_scene(&scene), m_rendered(false) { }
 
diff --git a/libdimensionxx/scene.cpp b/libdimensionxx/scene.cpp
index 2b0fba5..fec961a 100644
--- a/libdimensionxx/scene.cpp
+++ b/libdimensionxx/scene.cpp
@@ -27,7 +27,7 @@ namespace Dimension
     : m_scene(new dmnsn_scene*(dmnsn_new_scene())), m_camera(camera.copy()),
       m_canvas(new Canvas(canvas))
   {
-    if (!m_scene) {
+    if (!dmnsn()) {
       throw Dimension_Error("Couldn't allocate scene.");
     }