stk-code_catmod/src/tracks/graph_node.cpp
hikerstk b9e4325560 Added 'early targeting': the rubber ball will align its relative position
to the center of the track according to the relative distance of its target
(more precisely: it will move the interpolation control points). This
results in the ball being better align when it switches to aim-directly-at-
target mode, meaning that the target-distance can be reduced, hopefully
reducing the frequency with which tunneling happens.


git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@10016 178a84e3-b1eb-0310-8ba1-8eac791a3b58
2011-10-18 20:14:03 +00:00

230 lines
9.8 KiB
C++

// $Id$
//
// SuperTuxKart - a fun racing game with go-kart
// Copyright (C) 2009 Joerg Henrichs
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 3
// 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, B
#include "tracks/quad_graph.hpp"
#include "config/user_config.hpp"
#include "graphics/irr_driver.hpp"
#include "io/file_manager.hpp"
#include "io/xml_node.hpp"
#include "tracks/quad_graph.hpp"
#include "tracks/quad_set.hpp"
// A static variable that gives a single graph node easy access to
// all quads and avoids unnecessary parameters in many calls.
QuadSet *GraphNode::m_all_quads=NULL;
// This static variable gives a node access to the graph, and therefore
// to the quad to which a graph node index belongs.
QuadGraph *GraphNode::m_all_nodes=NULL;
// ----------------------------------------------------------------------------
/** Constructor. Saves the quad index which belongs to this graph node.
* \param index Index of the quad to use for this node (in m_all_quads).
*/
GraphNode::GraphNode(unsigned int quad_index, unsigned int node_index)
{
assert(quad_index<m_all_quads->getNumberOfQuads());
m_quad_index = quad_index;
m_node_index = node_index;
m_predecessor = -1;
m_distance_from_start = 0;
const Quad &quad = m_all_quads->getQuad(m_quad_index);
// FIXME: the following values should depend on the actual orientation
// of the quad. ATM we always assume that indices 0,1 are the lower end,
// and 2,3 are the upper end.
// The width is the average width at the beginning and at the end.
m_width = ( (quad[1]-quad[0]).length()
+ (quad[3]-quad[2]).length() ) * 0.5f;
m_lower_center = (quad[0]+quad[1]) * 0.5f;
m_upper_center = (quad[2]+quad[3]) * 0.5f;
m_line = core::line2df(m_lower_center.getX(), m_lower_center.getZ(),
m_upper_center.getX(), m_upper_center.getZ() );
// Only this 2d point is needed later
m_lower_center_2d = core::vector2df(m_lower_center.getX(),
m_lower_center.getZ() );
// The vector from the center of the quad to the middle of the right
// side of the quad
m_center_to_right = (quad[1]+quad[2])*0.5f - quad.getCenter();
} // GraphNode
// ----------------------------------------------------------------------------
/** Adds a successor to a node. This function will also pre-compute certain
* values (like distance from this node to the successor, angle (in world)
* between this node and the successor.
* \param to The index of the graph node of the successor.
*/
void GraphNode::addSuccessor(unsigned int to)
{
m_successor_node.push_back(to);
// m_quad_index is the quad index, so we use m_all_quads
const Quad &this_quad = m_all_quads->getQuad(m_quad_index);
// to is the graph node, so we have to use m_all_nodes to get the right quad
GraphNode &gn = m_all_nodes->getNode(to);
const Quad &next_quad = m_all_nodes->getQuadOfNode(to);
// Keep the first predecessor, which is usually the most 'natural' one.
if(gn.m_predecessor==-1)
gn.m_predecessor = m_node_index;
core::vector2df d2 = m_lower_center_2d
- m_all_nodes->getNode(to).m_lower_center_2d;
Vec3 diff = next_quad.getCenter() - this_quad.getCenter();
m_distance_to_next.push_back(d2.getLength());
float theta = atan2(diff.getX(), diff.getZ());
m_angle_to_next.push_back(theta);
// The length of this quad is the average of the left and right side
float distance_to_next = ( this_quad[2].distance(this_quad[1])
+ this_quad[3].distance(this_quad[0]) ) *0.5f;
// The distance from start for the successor node
if(to!=0)
{
float distance_for_next = m_distance_from_start+distance_to_next;
// If the successor node does not have a distance from start defined,
// update its distance. Otherwise if the node already has a distance,
// it is potentially necessary to update its distance from start:
// without this the length of the track (as taken by the distance
// from start of the last node) could be smaller than some of the
// paths. This can result in incorrect results for the arrival time
// estimation of the AI karts. See trac #354 for details.
if(m_all_nodes->getNode(to).m_distance_from_start==0)
{
m_all_nodes->getNode(to).m_distance_from_start = distance_for_next;
}
else if(m_all_nodes->getNode(to).m_distance_from_start
< distance_for_next)
{
float delta = distance_for_next
- m_all_nodes->getNode(to).getDistanceFromStart();
m_all_nodes->updateDistancesForAllSuccessors(to, delta);
}
}
} // addSuccessor
// ----------------------------------------------------------------------------
/** If this node has more than one successor, it will set up a vector that
* contains the direction to use when a certain graph node X should be
* reached.
*/
void GraphNode::setupPathsToNode()
{
if(m_successor_node.size()<2) return;
const unsigned int num_nodes = QuadGraph::get()->getNumNodes();
m_path_to_node.resize(num_nodes);
// Initialise each graph node with -1, indicating that
// it hasn't been reached yet.
for(unsigned int i=0; i<num_nodes; i++)
m_path_to_node[i] = -1;
// Indicate that this node can be reached from this node by following
// successor 0 - just a dummy value that might only be used during the
// recursion below.
m_path_to_node[m_node_index] = 0;
// A simple depth first search is used to determine which successor to
// use to reach a certain graph node. Using Dijkstra's algorithm would
// give the shortest way to reach a certain node, but the shortest way
// might involve some shortcuts which are hidden, and should therefore
// not be used.
for(unsigned int i=0; i<getNumberOfSuccessors(); i++)
{
GraphNode &gn = QuadGraph::get()->getNode(getSuccessor(i));
gn.markAllSuccessorsToUse(i, &m_path_to_node);
}
#ifdef DEBUG
for(unsigned int i=0; i<m_path_to_node.size(); i++)
{
if(m_path_to_node[i]==-1)
printf("[WARNING] No path to node %d found on graph node %d.\n",
i, m_node_index);
}
#endif
} // setupPathsToNode
// ----------------------------------------------------------------------------
/** This function marks that the successor n should be used to reach this
* node. It then recursively (depth first) does the same for all its
* successors. Depth-first
* \param n The successor which should be used in m_path_node to reach
* this node.
* \param path_to_node The path-to-node data structure of the node for
* which the paths are currently determined.
*/
void GraphNode::markAllSuccessorsToUse(unsigned int n,
PathToNodeVector *path_to_node)
{
// End recursion if the path to this node has already been found.
if( (*path_to_node)[m_node_index] >-1) return;
(*path_to_node)[m_node_index] = n;
for(unsigned int i=0; i<getNumberOfSuccessors(); i++)
{
GraphNode &gn = QuadGraph::get()->getNode(getSuccessor(i));
gn.markAllSuccessorsToUse(n, path_to_node);
}
} // markAllSuccesorsToUse
// ----------------------------------------------------------------------------
/** Returns the distance a point has from this quad in forward and sidewards
* direction, i.e. how far forwards the point is from the beginning of the
* quad, and how far to the side from the line connecting the center points
* is it. All these computations are done in 2D only.
* \param xyz The coordinates of the point.
* \param result The X coordinate contains the sidewards distance, the
* Z coordinate the forward distance.
*/
void GraphNode::getDistances(const Vec3 &xyz, Vec3 *result)
{
core::vector2df xyz2d(xyz.getX(), xyz.getZ());
core::vector2df closest = m_line.getClosestPoint(xyz2d);
if(m_line.getPointOrientation(xyz2d)>0)
result->setX( (closest-xyz2d).getLength()); // to the right
else
result->setX(-(closest-xyz2d).getLength()); // to the left
result->setZ( m_distance_from_start + (closest-m_lower_center_2d).getLength());
} // getDistances
// ----------------------------------------------------------------------------
/** Returns the square of the distance between the given point and any point
* on the 'centre' line, i.e. the finite line from the middle point of the
* lower end of the quad node to the middle point of the upper end of the
* quad which belongs to this graph node. The value is computed in 2d only!
* \param xyz The point for which the distance to the line is computed.
*/
float GraphNode::getDistance2FromPoint(const Vec3 &xyz)
{
core::vector2df xyz2d(xyz.getX(), xyz.getZ());
core::vector2df closest = m_line.getClosestPoint(xyz2d);
return (closest-xyz2d).getLengthSQ();
} // getDistance2FromPoint
// ----------------------------------------------------------------------------
void GraphNode::setChecklineRequirements(int latest_checkline)
{
m_checkline_requirements.push_back(latest_checkline);
}