Randomly generate blocks on a flat map

Question

I\'m trying to randomly generate blocks on a flat map and make it so that they don\'t overlap each other. I have made a matrix (c# array) of the size of the map (500x500), t

Answer 1

You shouldn't be getting that many collisions.

Assuming your blocks were ALL 5 units wide and you're trying to fit them into a grid of 500,500 you would have 100*100 spaces for them at minimum, which gives 10,000 spaces into which to fit 1,000 blocks.

Try playing around with this code:

using System;
using System.Collections.Generic;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main()
        {
            var result = PlaceNonOverlappingBlocks(1000, 5, 500, 500);
        }

        static List PlaceNonOverlappingBlocks(int count, int maxBlockSize, int mapX, int mapY)
        {
            var map    = new bool[mapY, mapX];
            var rng    = new Random();
            var result = new List(count);
            int collisions = 0; 

            while (count > 0)
            {
                int size = rng.Next(1, maxBlockSize + 1);
                int x = rng.Next(0, mapX - size);
                int y = rng.Next(0, mapY - size);

                if (fits(map, x, y, size))
                {
                    result.Add(new Block(x, y, size));
                    addToMap(map, x, y, size);
                    --count;
                }
                else
                {
                    if (++collisions> 100000)
                        throw new InvalidOperationException("Hell has frozen over");
                }
            }

            // This is just for diagnostics, and can be removed.
            Console.WriteLine($"There were {collisions} collisions.");

            return result;
        }

        static void addToMap(bool[,] map, int px, int py, int size)
        {
            for (int x = px; x < px+size; ++x)
                for (int y = py; y < py + size; ++y)
                    map[y, x] = true;
        }

        static bool fits(bool[,] map, int px, int py, int size)
        {
            for (int x = px; x < px + size; ++x)
                for (int y = py; y < py + size; ++y)
                    if (map[y, x])
                        return false;

            return true;
        }

        internal class Block
        {
            public int X    { get; }
            public int Y    { get; }
            public int Size { get; }

            public Block(int x, int y, int size)
            {
                X = x;
                Y = y;
                Size = size;
            }
        }
    }
}