src/raycast.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2016 juhdanad, Daniel Juhasz <juhdanad@gmail.com>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include "raycast.h"
  21 #include "irr_v3d.h"
  22 #include "irr_aabb3d.h"
  23 #include "constants.h"
  24
  25 bool RaycastSort::operator() (const PointedThing &pt1,
  26         const PointedThing &pt2) const
  27 {
  28         // "nothing" can not be sorted
  29         assert(pt1.type != POINTEDTHING_NOTHING);
  30         assert(pt2.type != POINTEDTHING_NOTHING);
  31         // returns false if pt1 is nearer than pt2
  32         if (pt1.distanceSq < pt2.distanceSq) {
  33                 return false;
  34         }
  35
  36         if (pt1.distanceSq == pt2.distanceSq) {
  37                 // Sort them to allow only one order
  38                 if (pt1.type == POINTEDTHING_OBJECT)
  39                         return (pt2.type == POINTEDTHING_OBJECT
  40                                 && pt1.object_id < pt2.object_id);
  41
  42                 return (pt2.type == POINTEDTHING_OBJECT
  43                                 || pt1.node_undersurface < pt2.node_undersurface);
  44         }
  45         return true;
  46 }
  47
  48
  49 RaycastState::RaycastState(const core::line3d<f32> &shootline,
  50         bool objects_pointable, bool liquids_pointable) :
  51         m_shootline(shootline),
  52         m_iterator(shootline.start / BS, shootline.getVector() / BS),
  53         m_previous_node(m_iterator.m_current_node_pos),
  54         m_objects_pointable(objects_pointable),
  55         m_liquids_pointable(liquids_pointable)
  56 {
  57 }
  58
  59
  60 bool boxLineCollision(const aabb3f &box, const v3f &start,
  61         const v3f &dir, v3f *collision_point, v3s16 *collision_normal)
  62 {
  63         if (box.isPointInside(start)) {
  64                 *collision_point = start;
  65                 collision_normal->set(0, 0, 0);
  66                 return true;
  67         }
  68         float m = 0;
  69
  70         // Test X collision
  71         if (dir.X != 0) {
  72                 if (dir.X > 0)
  73                         m = (box.MinEdge.X - start.X) / dir.X;
  74                 else
  75                         m = (box.MaxEdge.X - start.X) / dir.X;
  76
  77                 if (m >= 0 && m <= 1) {
  78                         *collision_point = start + dir * m;
  79                         if ((collision_point->Y >= box.MinEdge.Y)
  80                                         && (collision_point->Y <= box.MaxEdge.Y)
  81                                         && (collision_point->Z >= box.MinEdge.Z)
  82                                         && (collision_point->Z <= box.MaxEdge.Z)) {
  83                                 collision_normal->set((dir.X > 0) ? -1 : 1, 0, 0);
  84                                 return true;
  85                         }
  86                 }
  87         }
  88
  89         // Test Y collision
  90         if (dir.Y != 0) {
  91                 if (dir.Y > 0)
  92                         m = (box.MinEdge.Y - start.Y) / dir.Y;
  93                 else
  94                         m = (box.MaxEdge.Y - start.Y) / dir.Y;
  95
  96                 if (m >= 0 && m <= 1) {
  97                         *collision_point = start + dir * m;
  98                         if ((collision_point->X >= box.MinEdge.X)
  99                                         && (collision_point->X <= box.MaxEdge.X)
 100                                         && (collision_point->Z >= box.MinEdge.Z)
 101                                         && (collision_point->Z <= box.MaxEdge.Z)) {
 102                                 collision_normal->set(0, (dir.Y > 0) ? -1 : 1, 0);
 103                                 return true;
 104                         }
 105                 }
 106         }
 107
 108         // Test Z collision
 109         if (dir.Z != 0) {
 110                 if (dir.Z > 0)
 111                         m = (box.MinEdge.Z - start.Z) / dir.Z;
 112                 else
 113                         m = (box.MaxEdge.Z - start.Z) / dir.Z;
 114
 115                 if (m >= 0 && m <= 1) {
 116                         *collision_point = start + dir * m;
 117                         if ((collision_point->X >= box.MinEdge.X)
 118                                         && (collision_point->X <= box.MaxEdge.X)
 119                                         && (collision_point->Y >= box.MinEdge.Y)
 120                                         && (collision_point->Y <= box.MaxEdge.Y)) {
 121                                 collision_normal->set(0, 0, (dir.Z > 0) ? -1 : 1);
 122                                 return true;
 123                         }
 124                 }
 125         }
 126         return false;
 127 }