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Add Debug Maze Generation to Prims #9

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48 changes: 48 additions & 0 deletions Projects/Maze/Prims/Graph.cs
Original file line number Diff line number Diff line change
Expand Up @@ -31,5 +31,53 @@ public Graph(Node[] nodes)
{
Nodes = nodes ?? throw new ArgumentNullException(nameof(nodes));
}

public static Maze.Tile[,] ConvertToGrid(Graph graph, int rows, int columns, Func<int, int, int> index, int start_row, int start_column, int end_row, int end_column)
{
var tiles = new Maze.Tile[rows, columns];

foreach (var node in graph.Nodes)
{
if (node == null)
continue;

(int, int) Unpack(int i) => (i % rows, i / rows);

var (row, col) = Unpack(node.OwnIndex);

// directional
if (node.Connections.Contains(index(row - 1, col)))
{
tiles[row, col] |= Maze.Tile.Up;
tiles[row - 1, col] |= Maze.Tile.Down;
}
if (node.Connections.Contains(index(row + 1, col)))
{
tiles[row, col] |= Maze.Tile.Down;
tiles[row + 1, col] |= Maze.Tile.Up;
}
if (node.Connections.Contains(index(row, col - 1)))
{
tiles[row, col] |= Maze.Tile.Left;
tiles[row, col - 1] |= Maze.Tile.Right;
}
if (node.Connections.Contains(index(row, col + 1)))
{
tiles[row, col] |= Maze.Tile.Right;
tiles[row, col + 1] |= Maze.Tile.Left;
}

// start/end
if (row == start_row && col == start_column)
{
tiles[row, col] |= Maze.Tile.Start;
}
if (row == end_row && col == end_column)
{
tiles[row, col] |= Maze.Tile.End;
}
}
return tiles;
}
}
}
49 changes: 0 additions & 49 deletions Projects/Maze/Prims/PrimsAlgorithm.cs
Original file line number Diff line number Diff line change
Expand Up @@ -5,55 +5,6 @@ namespace Prims
{
public static class PrimsAlgorithm
{
private readonly struct TwoWayConnection : IComparable<TwoWayConnection>
{
public readonly int IndexA;
public readonly int IndexB;
public readonly double Cost;

public TwoWayConnection(int indexA, int indexB, double cost)
{
IndexA = indexA;
IndexB = indexB;
Cost = cost;
}

public int CompareTo(TwoWayConnection other) => other.Cost.CompareTo(Cost); // inversed because of how the heap works
}

public static Graph SimplePrims(Graph graph)
{
var newGraph = new Graph(new Graph.Node[graph.Nodes.Length]);
var nodes = graph.Nodes;
var current = nodes[0];
newGraph.Nodes[0] = new Graph.Node(0);

var heap = new HeapArray<TwoWayConnection>();

while (true)
{
for (int i = 0; i < current.Connections.Count; i++)
{
heap.Enqueue(new TwoWayConnection(current.OwnIndex, current.Connections[i], current.Costs[i]));
}

TwoWayConnection c;
do
{
if (heap.Count == 0)
{
return newGraph;
}
c = heap.Dequeue();
}
while (newGraph.Nodes[c.IndexB] != null);

newGraph.Nodes[c.IndexA].Add(c.IndexB, c.Cost);

newGraph.Nodes[c.IndexB] = new Graph.Node(c.IndexB);
current = graph.Nodes[c.IndexB];
newGraph.Nodes[c.IndexB].Add(c.IndexA, c.Cost);
}
}
}
}
104 changes: 71 additions & 33 deletions Projects/Maze/Prims/PrimsMazeGenerator.cs
Original file line number Diff line number Diff line change
@@ -1,4 +1,6 @@
using System;
// #define DebugMazeGeneration
using System;
using Towel.DataStructures;

namespace Prims
{
Expand Down Expand Up @@ -45,49 +47,85 @@ public class PrimsMazeGenerator
}
}

var res = PrimsAlgorithm.SimplePrims(new Graph(grid));
var graph = new Graph(grid);

#if DebugMazeGeneration

Console.Clear();
Console.WriteLine(Maze.Render(Graph.ConvertToGrid(graph, rows, columns, Index, start_row.Value, start_column.Value, end_row.Value, end_column.Value)));
Console.WriteLine("Press Enter To Continue...");
Console.ReadLine();
var res = SimplePrims(graph, rows, columns, Index, start_row.Value, start_column.Value, end_row.Value, end_column.Value);
#else
var res = SimplePrims(graph);
#endif

var tiles = new Maze.Tile[rows, columns];
return Graph.ConvertToGrid(res, rows, columns, Index, start_row.Value, start_column.Value, end_row.Value, end_column.Value);
}

private readonly struct TwoWayConnection : IComparable<TwoWayConnection>
{
public readonly int IndexA;
public readonly int IndexB;
public readonly double Cost;

foreach (var node in res.Nodes)
public TwoWayConnection(int indexA, int indexB, double cost)
{
(int, int) Unpack(int i) => (i % rows, i / rows);
IndexA = indexA;
IndexB = indexB;
Cost = cost;
}

var (row, col) = Unpack(node.OwnIndex);
public int CompareTo(TwoWayConnection other) => other.Cost.CompareTo(Cost); // inversed because of how the heap works
}

// directional
if (node.Connections.Contains(Index(row - 1, col)))
{
tiles[row, col] |= Maze.Tile.Up;
tiles[row - 1, col] |= Maze.Tile.Down;
}
if (node.Connections.Contains(Index(row + 1, col)))
{
tiles[row, col] |= Maze.Tile.Down;
tiles[row + 1, col] |= Maze.Tile.Up;
}
if (node.Connections.Contains(Index(row, col - 1)))
{
tiles[row, col] |= Maze.Tile.Left;
tiles[row, col - 1] |= Maze.Tile.Right;
}
if (node.Connections.Contains(Index(row, col + 1)))
{
tiles[row, col] |= Maze.Tile.Right;
tiles[row, col + 1] |= Maze.Tile.Left;
}
public static Graph SimplePrims(Graph graph
#if DebugMazeGeneration
, int rows, int columns, Func<int, int, int> index, int start_row, int start_column, int end_row, int end_column
#endif

)
{
var newGraph = new Graph(new Graph.Node[graph.Nodes.Length]);
var nodes = graph.Nodes;
var current = nodes[0];
newGraph.Nodes[0] = new Graph.Node(0);

// start/end
if (row == start_row.Value && col == start_column.Value)
var heap = new HeapArray<TwoWayConnection>();

while (true)
{
for (int i = 0; i < current.Connections.Count; i++)
{
tiles[row, col] |= Maze.Tile.Start;
heap.Enqueue(new TwoWayConnection(current.OwnIndex, current.Connections[i], current.Costs[i]));
}
if (row == end_row.Value && col == end_column.Value)

TwoWayConnection c;
do
{
tiles[row, col] |= Maze.Tile.End;
if (heap.Count == 0)
{
return newGraph;
}
c = heap.Dequeue();
}
while (newGraph.Nodes[c.IndexB] != null);

newGraph.Nodes[c.IndexA].Add(c.IndexB, c.Cost);

newGraph.Nodes[c.IndexB] = new Graph.Node(c.IndexB);
current = graph.Nodes[c.IndexB];
newGraph.Nodes[c.IndexB].Add(c.IndexA, c.Cost);

#if DebugMazeGeneration

Console.Clear();
Console.WriteLine(Maze.Render(Graph.ConvertToGrid(newGraph, rows, columns, index, start_row, start_column, end_row, end_column)));
Console.WriteLine("Press Enter To Continue...");
Console.ReadLine();

#endif
}
return tiles;
}
}
}