Added a graph class for representing and manipulating the game data

graph.cpp

@@ -0,0 +1,36 @@
+#include "graph.h"
+
+bool Graph::vertex_present(int x, int y, int size)
+{
+    int delta = size / 2;
+
+    int x_min = x - delta;
+    int x_max = x + delta;
+    int y_min = y - delta;
+    int y_max = y + delta;
+
+    for (list<Vertex>::iterator cursor = vertices.begin();
+	 cursor != vertices.end(); cursor++)
+    {
+	Vertex v = *cursor;
+	if (((x_min >= v.x_min && x_min <= x_max) &&
+	     ((y_min >= v.y_min && y_min <= y_max) ||
+	      (y_max >= v.y_min && y_max <= y_max))) ||
+	    ((x_max >= v.x_min && x_max <= x_max) &&
+	     ((y_min >= v.y_min && y_min <= y_max) ||
+	      (y_max >= v.y_min && y_max <= y_max))))
+	    return true;
+    }
+
+	return false;
+}
+
+void Graph::add_vertex(Vertex v)
+{
+    if (vertex_present(v.x, v.y)) return;
+
+    vertices.push_back(v);
+    edges.push_back(Edge(last_vertex, v));
+    last_vertex = v;
+}
+

graph.h

@@ -0,0 +1,48 @@
+/* Represents an undirected graph.
+ * Also contains the vertex and edge classes
+ * vertexes know their center point on the SDL Surface - 
+ * bad decoupling maybe, but not too bad, all things considered
+ */
+
+#ifndef _GRAPH_H_
+#define _GRAPH_H_
+
+#include <list>
+
+using std::list;
+
+struct Vertex
+{
+    int x;
+    int y;
+    int min_x;
+    int min_y;
+    int max_x;
+    int max_y;
+};
+
+struct Edge
+{
+    Vertex a;
+    Vertex b;
+};
+
+class Graph
+{
+ public:
+    Graph() {}
+
+    bool vertex_present(int x, int y, int size);
+
+    list<Vertex> get_vertices() { return vertices; }
+    list<Edge> get_edges() { return edges; }
+
+    void add_vertex(Vertex v);
+
+ private:
+    Vertex last_vertex;
+    list<Vertex> vertices;
+    list<Edge> edges;
+};
+
+#endif