treewars/graph.cpp

#include "graph.h"
#include "mathutils.h"
#include "debug.h"

Graph::Graph()
{
    current_vertex = NULL;
}

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

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

    return false;
}


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

    return false;
}


bool Graph::crosses_edge(Edge e)
{
    for (list<Edge>::iterator cursor = edges.begin();
	 cursor != edges.end(); cursor++)
    {
	Edge c = *cursor;
	if (MathUtils::lines_intersect(c.a->x, c.a->y, c.b->x, c.b->y,
				       e.a->x, e.a->y, e.b->x, e.b->y))
	    return true;
    }

    return false;
}


void Graph::do_vertex(int x, int y, int r)
{
    if (vertex_present(x, y, r)) select_vertex(x, y);
    else add_vertex(x, y, r);
}


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


void Graph::add_vertex(int x, int y, int r)
{
    Vertex* v = new Vertex(x, y, r);

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

    if (current_vertex == NULL)
    {
	current_vertex = v;
	vertices.push_back(v);
	return;
    }

    Edge e;
    e.a = current_vertex;
    e.b = v;

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

    vertices.push_back(v);
    edges.push_back(e);
    current_vertex = v;

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


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