From 6787a9219748575cd63aaadd483f49a4fd83b543 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@gmail.com>
Date: Sat, 9 Jan 2010 20:38:51 -0500
Subject: Implement reflection.

---
 libdimension/finish_combination.c | 40 +++++++++++++++++++++++++++++++++------
 1 file changed, 34 insertions(+), 6 deletions(-)

(limited to 'libdimension/finish_combination.c')

diff --git a/libdimension/finish_combination.c b/libdimension/finish_combination.c
index 045db96..bcfc1c9 100644
--- a/libdimension/finish_combination.c
+++ b/libdimension/finish_combination.c
@@ -34,10 +34,10 @@ dmnsn_finish_combination_fn(const dmnsn_finish *finish,
 {
   dmnsn_finish **params = finish->ptr;
   if (params[0]->finish_fn && params[1]->finish_fn) {
-    return dmnsn_color_add((*params[0]->finish_fn)(params[0], light, color, ray,
-                                                   normal, viewer),
-                           (*params[1]->finish_fn)(params[1], light, color, ray,
-                                                   normal, viewer));
+    return dmnsn_color_add(
+      (*params[0]->finish_fn)(params[0], light, color, ray, normal, viewer),
+      (*params[1]->finish_fn)(params[1], light, color, ray, normal, viewer)
+    );
   } else if (params[0]->finish_fn) {
     return (*params[0]->finish_fn)(params[0], light, color, ray,
                                    normal, viewer);
@@ -66,6 +66,26 @@ dmnsn_finish_combination_ambient_fn(const dmnsn_finish *finish,
   }
 }
 
+static dmnsn_color
+dmnsn_finish_combination_reflection_fn(const dmnsn_finish *finish,
+                                       dmnsn_color reflect, dmnsn_color color,
+                                       dmnsn_vector ray, dmnsn_vector normal)
+{
+  dmnsn_finish **params = finish->ptr;
+  if (params[0]->reflection_fn && params[1]->reflection_fn) {
+    return dmnsn_color_add(
+      (*params[0]->reflection_fn)(params[0], reflect, color, ray, normal),
+      (*params[1]->reflection_fn)(params[1], reflect, color, ray, normal)
+    );
+  } else if (params[0]->reflection_fn) {
+    return (*params[0]->reflection_fn)(params[0], reflect, color, ray, normal);
+  } else if (params[1]->reflection_fn) {
+    return (*params[1]->reflection_fn)(params[1], reflect, color, ray, normal);
+  } else {
+    return dmnsn_black;
+  }
+}
+
 static void
 dmnsn_finish_combination_free_fn(void *ptr)
 {
@@ -93,8 +113,16 @@ dmnsn_new_finish_combination(dmnsn_finish *f1, dmnsn_finish *f2)
       params[1] = f2;
 
       finish->ptr        = params;
-      finish->finish_fn  = &dmnsn_finish_combination_fn;
-      finish->ambient_fn = &dmnsn_finish_combination_ambient_fn;
+
+      if (f1->finish_fn || f2->finish_fn)
+        finish->finish_fn = &dmnsn_finish_combination_fn;
+
+      if (f1->ambient_fn || f2->ambient_fn)
+        finish->ambient_fn = &dmnsn_finish_combination_ambient_fn;
+
+      if (f1->reflection_fn || f2->reflection_fn)
+        finish->reflection_fn = &dmnsn_finish_combination_reflection_fn;
+
       finish->free_fn    = &dmnsn_finish_combination_free_fn;
 
       return finish;
-- 
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