5 files changed, 55 insertions, 0 deletions
diff --git a/libdimension/canvas.c b/libdimension/canvas.c
index 2bcc502..8671402 100644
--- a/libdimension/canvas.c
+++ b/libdimension/canvas.c
@@ -72,6 +72,7 @@ dmnsn_canvas_set_pixel(dmnsn_canvas *canvas, size_t x, size_t y,
 {
   dmnsn_assert(x < canvas->width && y < canvas->height,
                "Canvas access out of bounds.");
+  dmnsn_assert(!dmnsn_tcolor_isnan(tcolor), "Pixel has NaN component.");
 
   /* Set the pixel */
   canvas->pixels[y*canvas->width + x] = tcolor;
diff --git a/libdimension/dimension/color.h b/libdimension/dimension/color.h
index 34f3884..967e9a5 100644
--- a/libdimension/dimension/color.h
+++ b/libdimension/dimension/color.h
@@ -164,6 +164,13 @@ dmnsn_color_saturate(dmnsn_color color)
   return color;
 }
 
+/** Return whether a color contains any NaN components. */
+DMNSN_INLINE bool
+dmnsn_color_isnan(dmnsn_color color)
+{
+  return isnan(color.R) || isnan(color.G) || isnan(color.B);
+}
+
 /* Standard colors */
 
 /** Black. */
diff --git a/libdimension/dimension/geometry.h b/libdimension/dimension/geometry.h
index 80da735..38afa3b 100644
--- a/libdimension/dimension/geometry.h
+++ b/libdimension/dimension/geometry.h
@@ -445,3 +445,39 @@ dmnsn_bounding_box_is_infinite(dmnsn_bounding_box box)
 {
   return box.min.x == -INFINITY;
 }
+
+/** Return whether a vector contains any NaN components. */
+DMNSN_INLINE bool
+dmnsn_vector_isnan(dmnsn_vector v)
+{
+  return isnan(v.x) || isnan(v.y) || isnan(v.z);
+}
+
+/** Return whether a matrix contains any NaN components. */
+DMNSN_INLINE bool
+dmnsn_matrix_isnan(dmnsn_matrix m)
+{
+  size_t i, j;
+  for (i = 0; i < 3; ++i) {
+    for (j = 0; j < 4; ++j) {
+      if (isnan(m.n[i][j])) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+/** Return whether a line contains any NaN entries. */
+DMNSN_INLINE bool
+dmnsn_line_isnan(dmnsn_line l)
+{
+  return dmnsn_vector_isnan(l.x0) || dmnsn_vector_isnan(l.n);
+}
+
+/** Return whether a bounding box has any NaN components. */
+DMNSN_INLINE bool
+dmnsn_bounding_box_isnan(dmnsn_bounding_box box)
+{
+  return dmnsn_vector_isnan(box.min) || dmnsn_vector_isnan(box.max);
+}
diff --git a/libdimension/dimension/object.h b/libdimension/dimension/object.h
index 9019c69..28cc266 100644
--- a/libdimension/dimension/object.h
+++ b/libdimension/dimension/object.h
@@ -134,6 +134,10 @@ dmnsn_object_intersection(const dmnsn_object *object, dmnsn_line line,
       intersection->object = object;
     }
 
+    dmnsn_assert(!isnan(intersection->t), "Intersection point is NaN.");
+    dmnsn_assert(!dmnsn_vector_isnan(intersection->normal),
+                 "Intersection normal is NaN.");
+
     return true;
   } else {
     return false;
diff --git a/libdimension/dimension/tcolor.h b/libdimension/dimension/tcolor.h
index 5ccec3b..50bdf8c 100644
--- a/libdimension/dimension/tcolor.h
+++ b/libdimension/dimension/tcolor.h
@@ -99,6 +99,13 @@ dmnsn_tcolor_saturate(dmnsn_tcolor tcolor)
   return tcolor;
 }
 
+/** Return whether a tcolor contains any NaN components. */
+DMNSN_INLINE bool
+dmnsn_tcolor_isnan(dmnsn_tcolor tcolor)
+{
+  return dmnsn_color_isnan(tcolor.c) || isnan(tcolor.T) || isnan(tcolor.F);
+}
+
 /* Standard tcolors */
 
 /** Clear. */