Make finish callback a propper BRDF.

2 files changed, 14 insertions, 3 deletions

diff --git a/libdimension/dimension/geometry.h b/libdimension/dimension/geometry.h
index 86a0111..08ac1b3 100644
--- a/libdimension/dimension/geometry.h
+++ b/libdimension/dimension/geometry.h
@@ -77,6 +77,14 @@ dmnsn_line_construct(dmnsn_vector x0, dmnsn_vector n)
 /* Vector and matrix arithmetic */
 
 DMNSN_INLINE dmnsn_vector
+dmnsn_vector_negate(dmnsn_vector rhs)
+{
+  /* 3 negations */
+  dmnsn_vector v = { -rhs.x, -rhs.y, -rhs.z };
+  return v;
+}
+
+DMNSN_INLINE dmnsn_vector
 dmnsn_vector_add(dmnsn_vector lhs, dmnsn_vector rhs)
 {
   /* 3 additions */
diff --git a/libdimension/dimension/texture.h b/libdimension/dimension/texture.h
index 4d0e2d7..e5a1bfd 100644
--- a/libdimension/dimension/texture.h
+++ b/libdimension/dimension/texture.h
@@ -58,12 +58,15 @@ typedef struct dmnsn_finish dmnsn_finish;
 
 /* Finish callback */
 typedef dmnsn_color dmnsn_finish_fn(const dmnsn_finish *finish,
-                                    dmnsn_color color, dmnsn_vector x0,
-                                    dmnsn_vector normal,
-                                    dmnsn_vector reflected);
+                                    dmnsn_color light, dmnsn_color color,
+                                    dmnsn_vector ray, dmnsn_vector normal,
+                                    dmnsn_vector viewer);
 
 /* dmnsn_finish definition */
 struct dmnsn_finish {
+  /* Ambient contribution factor */
+  double ambient;
+
   /* Callbacks */
   dmnsn_finish_fn *finish_fn;
   dmnsn_free_fn *free_fn;