1 files changed, 56 insertions, 0 deletions
diff --git a/libdimension/pattern/gradient.c b/libdimension/pattern/gradient.c
new file mode 100644
index 0000000..f7a2b97
--- /dev/null
+++ b/libdimension/pattern/gradient.c
@@ -0,0 +1,56 @@
+/*************************************************************************
+ * Copyright (C) 2010-2014 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
+ * Gradient pattern.
+ */
+
+#include "dimension/pattern.h"
+
+/// Gradient pattern type.
+typedef struct dmnns_gradient {
+  dmnsn_pattern pattern;
+  dmnsn_vector orientation;
+} dmnsn_gradient;
+
+/// Gradient pattern callback.
+static double
+dmnsn_gradient_pattern_fn(const dmnsn_pattern *pattern, dmnsn_vector v)
+{
+  const dmnsn_gradient *gradient = (const dmnsn_gradient *)pattern;
+  double n = fmod(dmnsn_vector_dot(gradient->orientation, v), 1.0);
+  if (n < -dmnsn_epsilon) {
+    n += 1.0;
+  }
+  return n;
+}
+
+dmnsn_pattern *
+dmnsn_new_gradient_pattern(dmnsn_pool *pool, dmnsn_vector orientation)
+{
+  dmnsn_gradient *gradient = DMNSN_PALLOC(pool, dmnsn_gradient);
+  gradient->orientation = dmnsn_vector_normalized(orientation);
+
+  dmnsn_pattern *pattern = &gradient->pattern;
+  dmnsn_init_pattern(pattern);
+  pattern->pattern_fn = dmnsn_gradient_pattern_fn;
+  return pattern;
+}