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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;
}
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