Calculate transformed surface normals correctly.

1 files changed, 9 insertions, 3 deletions

diff --git a/libdimension/kD_splay_tree.c b/libdimension/kD_splay_tree.c
index ca31b86..b6be801 100644
--- a/libdimension/kD_splay_tree.c
+++ b/libdimension/kD_splay_tree.c
@@ -359,9 +359,15 @@ dmnsn_kD_splay_search_recursive(dmnsn_kD_splay_node *node, dmnsn_line ray,
         /* Transform the intersection back to the observer's view */
         result.intersection->ray = ray;
         result.intersection->normal = dmnsn_vector_normalize(
-          dmnsn_matrix_vector_mul(
-            node->object->trans,
-            result.intersection->normal
+          dmnsn_vector_sub(
+            dmnsn_matrix_vector_mul(
+              node->object->trans,
+              result.intersection->normal
+            ),
+            dmnsn_matrix_vector_mul(
+              node->object->trans,
+              dmnsn_zero
+            )
           )
         );
       } else {