1 files changed, 67 insertions, 0 deletions
diff --git a/libdimension/phong.c b/libdimension/phong.c
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--- /dev/null
+++ b/libdimension/phong.c
@@ -0,0 +1,67 @@
+/*************************************************************************
+ * Copyright (C) 2009 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#include "dimension.h"
+#include <stdlib.h> /* For malloc */
+#include <math.h>
+
+/*
+ * Phong finish
+ */
+
+static dmnsn_color
+dmnsn_phong_finish_fn(const dmnsn_finish *finish,
+                      dmnsn_color light, dmnsn_color color,
+                      dmnsn_vector ray, dmnsn_vector normal,
+                      dmnsn_vector viewer)
+{
+  double *params = finish->ptr;
+
+  double specular = params[0];
+  double exp      = params[1];
+
+  dmnsn_vector proj = dmnsn_vector_mul(2*dmnsn_vector_dot(ray, normal), normal);
+  dmnsn_vector reflected = dmnsn_vector_sub(proj, ray);
+
+  double specular_factor = pow(dmnsn_vector_dot(reflected, viewer), exp);
+  return dmnsn_color_mul(specular*specular_factor, light);
+}
+
+/* A phong finish */
+dmnsn_finish *
+dmnsn_new_phong_finish(double specular, double exp)
+{
+  dmnsn_finish *finish = dmnsn_new_finish();
+  if (finish) {
+    double *params = malloc(2*sizeof(double));
+    if (!params) {
+      dmnsn_delete_finish(finish);
+      return NULL;
+    }
+
+    params[0] = specular;
+    params[1] = exp;
+
+    finish->ptr       = params;
+    finish->finish_fn = &dmnsn_phong_finish_fn;
+    finish->free_fn   = &free;
+  }
+  return finish;
+}