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/*************************************************************************
* Copyright (C) 2009-2011 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
* Objects.
*/
#include <stdbool.h>
/** A type to represent a ray-object intersection. */
typedef struct dmnsn_intersection {
dmnsn_line ray; /**< The ray that intersected. */
double t; /**< The line index that intersected. */
/** The surface normal at the intersection point. */
dmnsn_vector normal;
/** The texture at the intersection point. */
const dmnsn_texture *texture;
/** The interior at the intersection point. */
const dmnsn_interior *interior;
} dmnsn_intersection;
/* Forward-declare dmnsn_object */
typedef struct dmnsn_object dmnsn_object;
/**
* Object initialization callback.
* @param[in,out] object The object to initialize.
*/
typedef void dmnsn_object_initialize_fn(dmnsn_object *object);
/**
* Ray-object intersection callback.
* @param[in] object The object to test.
* @param[in] line The line to test.
* @param[out] intersection Where to store the intersection details of the
* closest (if any) intersection.
* @return Whether \p line intersected \p object.
*/
typedef bool dmnsn_object_intersection_fn(const dmnsn_object *object,
dmnsn_line line,
dmnsn_intersection *intersection);
/**
* Object inside callback.
* @param[in] object The object to test.
* @param[in] point The point to test.
* @return Whether \p point is inside \p object.
*/
typedef bool dmnsn_object_inside_fn(const dmnsn_object *object,
dmnsn_vector point);
/** An object. */
struct dmnsn_object {
dmnsn_texture *texture; /**< Surface properties. */
dmnsn_interior *interior; /**< Interior properties. */
dmnsn_matrix trans; /**< Transformation matrix. */
dmnsn_matrix trans_inv; /**< Inverse of the transformation matrix. */
dmnsn_bounding_box bounding_box; /**< Object bounding box. */
/** Child objects. This array lists objects that can be split into
sub-objects for bounding purposes (for unions and meshes, for example). */
dmnsn_array *children;
dmnsn_object_initialize_fn *initialize_fn; /**< Initialization callback. */
dmnsn_object_intersection_fn *intersection_fn; /**< Intersection callback. */
dmnsn_object_inside_fn *inside_fn; /**< Inside callback. */
dmnsn_free_fn *free_fn; /**< Destruction callback. */
/** Generic pointer for object info. */
void *ptr;
/** @internal Reference count. */
dmnsn_refcount refcount;
};
/**
* Allocate a dummy object.
* @return The allocated object.
*/
dmnsn_object *dmnsn_new_object(void);
/**
* Free an object
* @param[in,out] object The object to destroy.
*/
void dmnsn_delete_object(dmnsn_object *object);
/**
* Initialize an object and potentially its children.
* @param[in,out] object The object to initialize.
*/
void dmnsn_initialize_object(dmnsn_object *object);
/**
* Transform a surface normal vector.
* @param[in] trans The transformation matrix.
* @param[in] normal The normal vector to transform
* @return The transformed normal vector.
*/
DMNSN_INLINE dmnsn_vector
dmnsn_transform_normal(dmnsn_matrix trans, dmnsn_vector normal)
{
return dmnsn_vector_normalized(
dmnsn_vector_sub(
dmnsn_transform_vector(trans, normal),
/* Optimized form of dmnsn_transform_vector(trans, dmnsn_zero) */
dmnsn_new_vector(trans.n[0][3], trans.n[1][3], trans.n[2][3])
)
);
}
/**
* Appropriately transform a ray, then test for an intersection.
* @param[in] object The object to test.
* @param[in] line The ray to test.
* @param[out] intersection Where to store the intersection details.
* @return Whether there was an intersection.
*/
DMNSN_INLINE bool
dmnsn_object_intersection(const dmnsn_object *object, dmnsn_line line,
dmnsn_intersection *intersection)
{
dmnsn_line line_trans = dmnsn_transform_line(object->trans_inv, line);
if (object->intersection_fn(object, line_trans, intersection)) {
/* Get us back into world coordinates */
intersection->ray = line;
intersection->normal = dmnsn_transform_normal(object->trans,
intersection->normal);
return true;
} else {
return false;
}
}
/**
* Appropriately transform a point, then test for containment.
* @param[in] object The object to test.
* @param[in] point The point to test.
* @return Whether \p point was inside \p object.
*/
DMNSN_INLINE bool
dmnsn_object_inside(const dmnsn_object *object, dmnsn_vector point)
{
point = dmnsn_transform_vector(object->trans_inv, point);
return object->inside_fn(object, point);
}
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