minetest/src/raycast.cpp

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/*
Minetest
Copyright (C) 2016 juhdanad, Daniel Juhasz <juhdanad@gmail.com>
This program 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 2.1 of the License, or
(at your option) any later version.
This program 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, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "raycast.h"
#include "irr_v3d.h"
#include "irr_aabb3d.h"
#include <quaternion.h>
#include "constants.h"
bool RaycastSort::operator() (const PointedThing &pt1,
const PointedThing &pt2) const
{
// "nothing" cannot be sorted
assert(pt1.type != POINTEDTHING_NOTHING);
assert(pt2.type != POINTEDTHING_NOTHING);
f32 pt1_distSq = pt1.distanceSq;
// Add some bonus when one of them is an object
if (pt1.type != pt2.type) {
if (pt1.type == POINTEDTHING_OBJECT)
pt1_distSq -= BS * BS;
else if (pt2.type == POINTEDTHING_OBJECT)
pt1_distSq += BS * BS;
}
// returns false if pt1 is nearer than pt2
if (pt1_distSq < pt2.distanceSq) {
return false;
}
if (pt1_distSq == pt2.distanceSq) {
// Sort them to allow only one order
if (pt1.type == POINTEDTHING_OBJECT)
return (pt2.type == POINTEDTHING_OBJECT
&& pt1.object_id < pt2.object_id);
return (pt2.type == POINTEDTHING_OBJECT
|| pt1.node_undersurface < pt2.node_undersurface);
}
return true;
}
RaycastState::RaycastState(const core::line3d<f32> &shootline,
bool objects_pointable, bool liquids_pointable,
const std::optional<Pointabilities> &pointabilities) :
m_shootline(shootline),
m_iterator(shootline.start / BS, shootline.getVector() / BS),
m_previous_node(m_iterator.m_current_node_pos),
m_objects_pointable(objects_pointable),
m_liquids_pointable(liquids_pointable),
m_pointabilities(pointabilities)
{
}
bool boxLineCollision(const aabb3f &box, const v3f &start,
const v3f &dir, v3f *collision_point, v3f *collision_normal)
{
if (box.isPointInside(start)) {
*collision_point = start;
collision_normal->set(0, 0, 0);
return true;
}
float m = 0;
// Test X collision
if (dir.X != 0) {
if (dir.X > 0)
m = (box.MinEdge.X - start.X) / dir.X;
else
m = (box.MaxEdge.X - start.X) / dir.X;
if (m >= 0 && m <= 1) {
*collision_point = start + dir * m;
if ((collision_point->Y >= box.MinEdge.Y)
&& (collision_point->Y <= box.MaxEdge.Y)
&& (collision_point->Z >= box.MinEdge.Z)
&& (collision_point->Z <= box.MaxEdge.Z)) {
collision_normal->set((dir.X > 0) ? -1 : 1, 0, 0);
return true;
}
}
}
// Test Y collision
if (dir.Y != 0) {
if (dir.Y > 0)
m = (box.MinEdge.Y - start.Y) / dir.Y;
else
m = (box.MaxEdge.Y - start.Y) / dir.Y;
if (m >= 0 && m <= 1) {
*collision_point = start + dir * m;
if ((collision_point->X >= box.MinEdge.X)
&& (collision_point->X <= box.MaxEdge.X)
&& (collision_point->Z >= box.MinEdge.Z)
&& (collision_point->Z <= box.MaxEdge.Z)) {
collision_normal->set(0, (dir.Y > 0) ? -1 : 1, 0);
return true;
}
}
}
// Test Z collision
if (dir.Z != 0) {
if (dir.Z > 0)
m = (box.MinEdge.Z - start.Z) / dir.Z;
else
m = (box.MaxEdge.Z - start.Z) / dir.Z;
if (m >= 0 && m <= 1) {
*collision_point = start + dir * m;
if ((collision_point->X >= box.MinEdge.X)
&& (collision_point->X <= box.MaxEdge.X)
&& (collision_point->Y >= box.MinEdge.Y)
&& (collision_point->Y <= box.MaxEdge.Y)) {
collision_normal->set(0, 0, (dir.Z > 0) ? -1 : 1);
return true;
}
}
}
return false;
}
bool boxLineCollision(const aabb3f &box, const v3f &rotation,
const v3f &start, const v3f &dir,
v3f *collision_point, v3f *collision_normal, v3f *raw_collision_normal)
{
// Inversely transform the ray rather than rotating the box faces;
// this allows us to continue using a simple ray - AABB intersection
core::quaternion rot(rotation * core::DEGTORAD);
rot.makeInverse();
bool collision = boxLineCollision(box, rot * start, rot * dir, collision_point, collision_normal);
if (!collision) return collision;
// Transform the results back
rot.makeInverse();
*collision_point = rot * *collision_point;
*raw_collision_normal = *collision_normal;
*collision_normal = rot * *collision_normal;
return collision;
}