/*************************************************************************
 * 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 "internal.h"
#include "dimension/model.h"
#include <stdlib.h>

// Allocate a dummy object
dmnsn_object *
dmnsn_new_object(dmnsn_pool *pool)
{
  dmnsn_object *object = DMNSN_PALLOC(pool, dmnsn_object);
  dmnsn_init_object(object);
  return object;
}

// Initialize a dmnsn_object field
void
dmnsn_init_object(dmnsn_object *object)
{
  object->vtable = NULL;
  object->texture = NULL;
  object->interior = NULL;
  object->trans = dmnsn_identity_matrix();
  object->intrinsic_trans = dmnsn_identity_matrix();
  object->children = NULL;
  object->split_children = false;
  object->precomputed = false;
}

/// Recursively precompute objects.
static void
dmnsn_object_precompute_recursive(dmnsn_object *object, dmnsn_matrix pigment_trans)
{
  dmnsn_assert(!object->precomputed, "Object double-precomputed.");
  object->precomputed = true;

  const dmnsn_object_vtable *vtable = object->vtable;
  dmnsn_assert(vtable->intersection_fn, "Missing intersection function.");
  dmnsn_assert(vtable->inside_fn, "Missing inside function.");
  dmnsn_assert(vtable->bounding_fn || vtable->precompute_fn, "Missing bounding and precompute function.");

  // Initialize the texture
  if (!object->texture->initialized) {
    dmnsn_texture_initialize(object->texture);
  }

  dmnsn_matrix total_trans = dmnsn_matrix_mul(object->trans, object->intrinsic_trans);

  // Precompute the object's children
  if (object->children) {
    DMNSN_ARRAY_FOREACH (dmnsn_object **, child, object->children) {
      dmnsn_matrix saved_trans = (*child)->trans;
      (*child)->trans = dmnsn_matrix_mul(total_trans, saved_trans);

      dmnsn_matrix child_pigment_trans;
      if ((*child)->texture == NULL || (*child)->texture->pigment == NULL) {
        // Don't transform cascaded pigments with the child object
        child_pigment_trans = pigment_trans;
      } else {
        child_pigment_trans = dmnsn_matrix_inverse((*child)->trans);
      }

      dmnsn_texture_cascade(object->texture, &(*child)->texture);
      dmnsn_interior_cascade(object->interior, &(*child)->interior);
      dmnsn_object_precompute_recursive(*child, child_pigment_trans);
      (*child)->trans = saved_trans;
    }
  }

  // Precalculate object values
  object->pigment_trans = pigment_trans;
  object->trans_inv = dmnsn_matrix_inverse(total_trans);
  if (vtable->bounding_fn) {
    object->aabb = vtable->bounding_fn(object, total_trans);
  }
  if (vtable->precompute_fn) {
    vtable->precompute_fn(object);
  }
}

// Precompute object properties
void
dmnsn_object_precompute(dmnsn_object *object)
{
  dmnsn_matrix pigment_trans = dmnsn_matrix_inverse(object->trans);
  dmnsn_object_precompute_recursive(object, pigment_trans);
}