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/*************************************************************************
* Copyright (C) 2009-2014 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
* Objects.
*/
#include <stdbool.h>
/* Forward-declare dmnsn_object */
typedef struct dmnsn_object dmnsn_object;
/** A type to represent a ray-object intersection. */
typedef struct dmnsn_intersection {
dmnsn_ray ray; /**< The ray that intersected. */
double t; /**< The ray index that intersected. */
/** The surface normal at the intersection point. */
dmnsn_vector normal;
/** The object of intersection. */
const dmnsn_object *object;
} dmnsn_intersection;
/**
* Ray-object intersection callback.
* @param[in] object The object to test.
* @param[in] ray The ray to test.
* @param[out] intersection Where to store the intersection details of the
* closest (if any) intersection.
* @return Whether \p ray intersected \p object.
*/
typedef bool dmnsn_object_intersection_fn(const dmnsn_object *object, dmnsn_ray ray, 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);
/**
* Object bounding callback.
* @param[in,out] object The object to bound.
* @param[in,out] trans The effective transformation for the object.
* @return A world-coordinate bounding box computed for the object.
*/
typedef dmnsn_aabb dmnsn_object_bounding_fn(const dmnsn_object *object, dmnsn_matrix trans);
/**
* Object precomputation callback.
* @param[in,out] object The object to precompute.
*/
typedef void dmnsn_object_precompute_fn(dmnsn_object *object);
/** Object callbacks. */
typedef struct dmnsn_object_vtable {
dmnsn_object_intersection_fn *intersection_fn; /**< Intersection callback. */
dmnsn_object_inside_fn *inside_fn; /**< Inside callback. */
dmnsn_object_bounding_fn *bounding_fn; /**< Bounding callback. */
dmnsn_object_precompute_fn *precompute_fn; /**< Precomputation callback. */
} dmnsn_object_vtable;
/** An object. */
struct dmnsn_object {
const dmnsn_object_vtable *vtable; /**< Callbacks. */
dmnsn_texture *texture; /**< Surface properties. */
dmnsn_interior *interior; /**< Interior properties. */
dmnsn_matrix trans; /**< Transformation matrix. */
dmnsn_matrix intrinsic_trans; /**< Transformations intrinsic to the object. */
dmnsn_array *children; /**< Child objects. */
bool split_children; /**< Whether the child objects can be split. */
/* Precomputed values */
bool precomputed; /**< @internal Whether the object is precomputed yet. */
dmnsn_matrix trans_inv; /**< Inverse of the transformation matrix. */
dmnsn_matrix pigment_trans; /**< Inverse transformation for the texture. */
dmnsn_aabb aabb; /**< Bounding box in world coordinates. */
};
/**
* Allocate a dummy object.
* @param[in] pool The memory pool to allocate from.
* @return The allocated object.
*/
dmnsn_object *dmnsn_new_object(dmnsn_pool *pool);
/**
* Initialize a dmnsn_object field.
* @param[out] object The object to initialize.
*/
void dmnsn_init_object(dmnsn_object *object);
/**
* Precompute values for an object and its children.
* @param[in,out] object The object to precompute.
*/
void dmnsn_object_precompute(dmnsn_object *object);
/**
* Appropriately transform a ray, then test for an intersection.
* @param[in] object The object to test.
* @param[in] ray 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_ray ray,
dmnsn_intersection *intersection)
{
dmnsn_ray ray_trans = dmnsn_transform_ray(object->trans_inv, ray);
intersection->object = NULL;
if (object->vtable->intersection_fn(object, ray_trans, intersection)) {
/* Get us back into world coordinates */
intersection->ray = ray;
intersection->normal = dmnsn_vector_normalized(
dmnsn_transform_normal(object->trans_inv, intersection->normal)
);
if (!intersection->object) {
intersection->object = object;
}
dmnsn_assert(!dmnsn_isnan(intersection->t), "Intersection point is NaN.");
dmnsn_assert(!dmnsn_vector_isnan(intersection->normal), "Intersection normal is NaN.");
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_point(object->trans_inv, point);
return object->vtable->inside_fn(object, point);
}
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