5 files changed, 28 insertions, 11 deletions
diff --git a/libdimension/canvas.c b/libdimension/canvas.c
index 975686d..b1b65e1 100644
--- a/libdimension/canvas.c
+++ b/libdimension/canvas.c
@@ -30,18 +30,13 @@
 dmnsn_canvas *
 dmnsn_new_canvas(size_t width, size_t height)
 {
-  /* Allocate the dmnsn_canvas struct */
   dmnsn_canvas *canvas = dmnsn_malloc(sizeof(dmnsn_canvas));
 
-  /* Set the width and height */
-  canvas->width  = width;
-  canvas->height = height;
-
-  /* Allocate room for the optimizers */
+  canvas->width      = width;
+  canvas->height     = height;
   canvas->optimizers = dmnsn_new_array(sizeof(dmnsn_canvas_optimizer));
-
-  /* Allocate the pixels */
-  canvas->pixels = dmnsn_malloc(sizeof(dmnsn_color)*width*height);
+  canvas->pixels     = dmnsn_malloc(sizeof(dmnsn_color)*width*height);
+  canvas->refcount   = dmnsn_new_refcount();
 
   return canvas;
 }
@@ -50,7 +45,9 @@ dmnsn_new_canvas(size_t width, size_t height)
 void
 dmnsn_delete_canvas(dmnsn_canvas *canvas)
 {
-  if (canvas) {
+  if (canvas && DMNSN_DECREF(canvas)) {
+    dmnsn_delete_refcount(canvas->refcount);
+
     /* Free the optimizers */
     DMNSN_ARRAY_FOREACH (dmnsn_canvas_optimizer *, i, canvas->optimizers) {
       if (i->free_fn) {
diff --git a/libdimension/dimension/canvas.h b/libdimension/dimension/canvas.h
index 6938c0e..f33fc88 100644
--- a/libdimension/dimension/canvas.h
+++ b/libdimension/dimension/canvas.h
@@ -39,6 +39,8 @@ typedef struct {
    * at (a,b) is accessible as pixels[b*width + a].
    */
   dmnsn_color *pixels;
+
+  dmnsn_refcount *refcount; /**< @internal Reference count. */
 } dmnsn_canvas;
 
 /* Forward-declare dmnsn_canvas_optimizer */
diff --git a/libdimension/dimension/scene.h b/libdimension/dimension/scene.h
index c182d85..ffe5fb3 100644
--- a/libdimension/dimension/scene.h
+++ b/libdimension/dimension/scene.h
@@ -93,6 +93,15 @@ void dmnsn_delete_scene(dmnsn_scene *scene);
 void dmnsn_initialize_scene(dmnsn_scene *scene);
 
 /**
+ * Set the output canvas for a scene.
+ * @param[in,out] scene   The scene for which to set the canvas.
+ * @param[in]     canvas  The canvas to set.
+ */
+void dmnsn_scene_set_canvas(dmnsn_scene *scene, dmnsn_canvas *canvas);
+
+/**
  * Add an object to a scene.
+ * @param[in,out] scene   The scene to which to add the object.
+ * @param[in]     object  The object to add.
  */
 void dmnsn_scene_add_object(dmnsn_scene *scene, dmnsn_object *object);
diff --git a/libdimension/scene.c b/libdimension/scene.c
index f5b76e7..51b8215 100644
--- a/libdimension/scene.c
+++ b/libdimension/scene.c
@@ -84,8 +84,17 @@ dmnsn_initialize_scene(dmnsn_scene *scene)
 }
 
 void
+dmnsn_scene_set_canvas(dmnsn_scene *scene, dmnsn_canvas *canvas)
+{
+  DMNSN_INCREF(canvas);
+  dmnsn_delete_canvas(scene->canvas);
+  scene->canvas = canvas;
+}
+
+void
 dmnsn_scene_add_object(dmnsn_scene *scene, dmnsn_object *object)
 {
+  DMNSN_INCREF(object);
   dmnsn_initialize_object(object);
   dmnsn_array_push(scene->objects, &object);
 }
diff --git a/libdimension/tests/render.c b/libdimension/tests/render.c
index a487224..f35f5bb 100644
--- a/libdimension/tests/render.c
+++ b/libdimension/tests/render.c
@@ -40,7 +40,7 @@ dmnsn_new_test_scene(void)
   );
 
   /* Allocate a canvas */
-  scene->canvas = dmnsn_new_canvas(768, 480);
+  dmnsn_scene_set_canvas(scene, dmnsn_new_canvas(768, 480));
 
   /* Set up the transformation matrix for the perspective camera */
   dmnsn_matrix trans = dmnsn_scale_matrix(