[Solved] Math.random creates a weird pattern

[ZodaInk]

I have no idea how this happens or even if this is a problem with Löve. While the pattern is almost random, it is not the kind of random I want.
Tell me if it works fine for you or if you find something in the code that is wrong.
The .love file creates a grid and every tile in that grid has a 90%(ish) chance of being a box, instead it creates this pattern...
The orange boxes are love.math.random(), the blue boxes are the regular math.random().

This is what it looks like when I run it:

game.love

(777 Bytes) Downloaded 133 times

I am genuinely confused...

[airstruck]

Why are you storing the random locations in 2d arrays? Wouldn't it be much simpler to store coordinate pairs in a 1d array?

Code: Select all

	for x = 0, math.floor(window.w / size) do
		for y = 0, math.floor(window.h / size) do
			if math.random() < 0.9 then
				index[#index + 1] = { x = x, y = y }
			end
		end
	end

Code: Select all

	for _, pos in ipairs(index) do
		love.graphics.rectangle("line",
		    pos.x * size + 2, pos.y * size + 2, size - 4, size - 4)
	end

[ZodaInk]

I usually would, don't know why I did it like this, but that is beside the point.
The point is that it doesn't create a noise-ish array of boxes, it's not even filling up anywhere near 90% of it.

Code: Select all

if math.random() < 0.9 then --[[code]] end

That should be true roughly 90% of the time, yet in my case it isn't.

[airstruck]

It's not beside the point, though. If you write code that's simple and easy to understand, it's probably going to work and you don't have to spend time trying to figure out why it doesn't work.

ss.png (13.51 KiB) Viewed 3110 times

[ZodaInk]

That did fix it...
Now I am even more confused, why would this fix it?

[Xugro]

Your idea of saving a sparse matrix is flawed. I just saved the full matrix and it works (see attached code). If you fill in 90% of the boxes then it is better to store the complete matrix.

Edit:

ipairs iterates over integer keys, starting from 1, until it finds one which is not in the table.

Source: http://lua-users.org/lists/lua-l/2004-12/msg00311.html

And since you have a table where not all rows are present your drawing function will stop at that row and does not print the boxes below.