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-rw-r--r--libdimension/reflective.c74
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diff --git a/libdimension/reflective.c b/libdimension/reflective.c
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+/*************************************************************************
+ * 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>
+
+/*
+ * Reflective finish
+ */
+
+typedef struct dmnsn_reflection_params {
+ dmnsn_color min, max;
+ double falloff;
+} dmnsn_reflection_params;
+
+static dmnsn_color
+dmnsn_reflective_finish_fn(const dmnsn_finish *finish,
+ dmnsn_color reflect, dmnsn_color color,
+ dmnsn_vector ray, dmnsn_vector normal)
+{
+ dmnsn_reflection_params *params = finish->ptr;
+ double reflection = pow(dmnsn_vector_dot(ray, normal), params->falloff);
+
+ return dmnsn_color_illuminate(
+ dmnsn_color_add(
+ dmnsn_color_mul(
+ reflection,
+ dmnsn_color_sub(params->max, params->min)
+ ),
+ params->min
+ ),
+ reflect
+ );
+}
+
+dmnsn_finish *
+dmnsn_new_reflective_finish(dmnsn_color min, dmnsn_color max, double falloff)
+{
+ dmnsn_finish *finish = dmnsn_new_finish();
+ if (finish) {
+ dmnsn_reflection_params *params = malloc(sizeof(dmnsn_reflection_params));
+ if (!params) {
+ dmnsn_delete_finish(finish);
+ return NULL;
+ }
+
+ params->min = min;
+ params->max = max;
+ params->falloff = falloff;
+
+ finish->ptr = params;
+ finish->reflection_fn = &dmnsn_reflective_finish_fn;
+ finish->free_fn = &free;
+ }
+ return finish;
+}