1 files changed, 67 insertions, 0 deletions
diff --git a/libdimension/reflection.c b/libdimension/reflection.c
new file mode 100644
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+++ b/libdimension/reflection.c
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+/*************************************************************************
+ * Copyright (C) 2010 Tavian Barnes <tavianator@tavianator.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/>.                                       *
+ *************************************************************************/
+
+/**
+ * @file
+ * Reflective finish.
+ */
+
+#include "dimension.h"
+#include <math.h>
+#include <stdlib.h>
+
+/** Reflective finish payload. */
+typedef struct dmnsn_reflection_params {
+  dmnsn_color min, max;
+  double falloff;
+} dmnsn_reflection_params;
+
+/** Reflective finish callback. */
+static dmnsn_color
+dmnsn_basic_reflection_fn(const dmnsn_reflection *reflection,
+                          dmnsn_color reflect, dmnsn_color color,
+                          dmnsn_vector ray, dmnsn_vector normal)
+{
+  dmnsn_reflection_params *params = reflection->ptr;
+  double coeff = pow(fabs(dmnsn_vector_dot(ray, normal)), params->falloff);
+
+  return dmnsn_color_illuminate(
+    dmnsn_color_gradient(params->min, params->max, coeff),
+    reflect
+  );
+}
+
+dmnsn_reflection *
+dmnsn_new_basic_reflection(dmnsn_color min, dmnsn_color max, double falloff)
+{
+  dmnsn_reflection *reflection = dmnsn_new_reflection();
+
+  dmnsn_reflection_params *params
+    = dmnsn_malloc(sizeof(dmnsn_reflection_params));
+  params->min     = min;
+  params->max     = max;
+  params->falloff = falloff;
+
+  reflection->reflection_fn = dmnsn_basic_reflection_fn;
+  reflection->free_fn       = dmnsn_free;
+  reflection->ptr           = params;
+
+  return reflection;
+}