treewars/graph.cpp

#include "graph.h"
#include "mathutils.h"
#include "debug.h"
#include <list>
#include <algorithm>
#include <cassert>

using std::list;

Graph::Graph(bool planar)
{
    this->planar = planar;
}

Graph::~Graph()
{
    for (list<Vertex*>::iterator cursor = vertices.begin();
	 cursor != vertices.end(); cursor++)
    {
	Vertex* v = *cursor;
	delete v;
    }
}


// In 3-space, this will be less useful, because we'll be clicking on the
// objects themselves... but we'll cross that bridge when we get there
bool Graph::point_in_vertex(int x, int y, int z)
{
    for (list<Vertex*>::iterator cursor = vertices.begin();
	 cursor != vertices.end(); cursor++)
    {
	Vertex* v = *cursor;
	if (MathUtils::distance(v->x, v->y, v->z, x, y, z) <= v->r)
	    return true;
    }

    return false;
}


Vertex * Graph::vertex_at(int x, int y, int z)
{
    for (list<Vertex*>::iterator cursor = vertices.begin();
	 cursor != vertices.end(); cursor++)
    {
	Vertex* v = *cursor;
	if (MathUtils::distance(v->x, v->y, v->z, x, y, z) <= v->r) return v;
    }

    return NULL;
}


bool Graph::vertex_would_overlap(int x, int y, int z, int r)
{
    for (list<Vertex*>::iterator cursor = vertices.begin();
	 cursor != vertices.end(); cursor++)
    {
	Vertex* v = *cursor;
	if (MathUtils::distance(v->x, v->y, v->z, x, y, z) <= v->r + r)
	    return true;
    }

    return false;
}


bool Graph::crosses_edge(Vertex* a, Vertex* b)
{
    for (list<Vertex*>::iterator cursor = vertices.begin();
	 cursor != vertices.end(); cursor++)
    {
	Vertex* v = *cursor;
	for (list<Vertex*>::iterator subcursor = v->neighbors.begin();
	     subcursor != v->neighbors.end(); subcursor++)
	{
	    Vertex* w = *subcursor;

	    if (MathUtils::lines_intersect(a->x, a->y, b->x, b->y,
					   v->x, v->y, w->x, w->y))
		return true;
	}
    }

    return false;
}


bool Graph::add_vertex(int x, int y, int z, int r, int colour, int score, Vertex* src)
{
    Vertex* v = new Vertex(x, y, z, r, colour, score);

    // Make sure the nodes won't overlap
    if (vertex_would_overlap(v->x, v->y, v->z, v->r))
    {
#ifdef DEBUG
	fprintf(stderr, "debug: Graph::add_vertex(): failed to add due to vertex collision: x=%d, y=%d, z=%d, r=%d\n", v->x, v->y, v->z, v->r);
#endif
	delete v;
	return false;
    }

    if (src != NULL)
    {
	if (planar && crosses_edge(v, src))
	{
#ifdef DEBUG
	    fprintf(stderr, "debug: Graph::add_vertex(): failed to add due to edge collision: x1=%d, y1=%d, x2=%d, y2=%d\n", v->x, v->y, src->x, src->y);
#endif
            delete v;
            return false;
	}

	v->neighbors.push_back(src);
	src->neighbors.push_back(v);
    }

    vertices.push_back(v);

#ifdef DEBUG
    fprintf(stderr, "debug: Graph::add_vertex(): added: x=%d, y=%d, z=%d, r=%d, score=%d, colour=%x\n", v->x, v->y, v->z, v->r, v->score, v->colour);
#endif

    return true;
}


list<Vertex*> Graph::get_colour(int colour)
{
    list<Vertex*> answer;

    for (list<Vertex*>::iterator cursor = vertices.begin();
	 cursor != vertices.end(); cursor++)
    {
	Vertex* v = *cursor;
	if (v->colour == colour) answer.push_back(v);
    }

    return answer;
}


void Graph::remove_vertex(Vertex* target)
{
    list<Vertex*>::iterator cursor;
    
    for (cursor = target->neighbors.begin(); cursor != target->neighbors.end();
	 cursor++)
    {
	list<Vertex*>::iterator subcursor = find((*cursor)->neighbors.begin(),
						 (*cursor)->neighbors.end(),
						 target);
	assert(subcursor != (*cursor)->neighbors.end());
	(*cursor)->neighbors.erase(subcursor);
    }
    
    cursor = find(vertices.begin(), vertices.end(), target);
    assert(cursor != vertices.end());
    vertices.erase(cursor);
    delete target;
}


Vertex::Vertex(int x, int y, int z, int r, int colour, int score)
{
    this->x = x;
    this->y = y;
    this->z = z;
    this->r = r;
    this->colour = colour;
    this->score = score;
}