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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
+ * Diffuse finish.
+ */
+
+#include "dimension.h"
+#include <math.h>
+#include <stdlib.h>
+
+/** Diffuse finish callback. */
+static dmnsn_color
+dmnsn_lambertian_diffuse_fn(const dmnsn_diffuse *diffuse,
+ dmnsn_color light, dmnsn_color color,
+ dmnsn_vector ray, dmnsn_vector normal)
+{
+ double *coeff = diffuse->ptr;
+ double diffuse_factor = fabs((*coeff)*dmnsn_vector_dot(ray, normal));
+ dmnsn_color ret
+ = dmnsn_color_mul(diffuse_factor, dmnsn_color_illuminate(light, color));
+ ret.filter = 0.0;
+ ret.trans = 0.0;
+ return ret;
+}
+
+dmnsn_diffuse *
+dmnsn_new_lambertian(double diffuse)
+{
+ dmnsn_diffuse *lambertian = dmnsn_new_diffuse();
+
+ double *param = dmnsn_malloc(sizeof(double));
+ *param = diffuse;
+
+ lambertian->diffuse_fn = dmnsn_lambertian_diffuse_fn;
+ lambertian->free_fn = dmnsn_free;
+ lambertian->ptr = param;
+
+ return lambertian;
+}