What Causes this pattern??

Questions
1

So I tried doing a 2D random terrain generation myself, it worked until I made so that the first generation stays as it is.
It now instead creates a diagonal mirror effect, wich is not what I’m looking for.

displayMode(FULLSCREEN)
    
function setup()
    worldSize=10
    size=HEIGHT/worldSize
    
    --Color related
    col={color(0,255,0,255), color(0,0,255,255)}
    terrGen={}
    
    
    --Random color generation (decided from 1 to amount of colors)
    for i=0, (HEIGHT//size) do
        for j=0, (HEIGHT//size) do
            --setting random numbers
            terrGen[i*j]=math.random(1, #col)
        end
    end
    
end

function draw()
    background(0)
    
    -------------------------------------My mistake is probally somwhere here
    for i=0, (HEIGHT/size) do
        for j=0, (HEIGHT/size) do
            
            --copying the numbers over to a variable
            local c = terrGen[i*j]
            
            --selecting the color from the col table using variable c's numbers
            fill(col[c])
            --drawing squares
            rect(i*size,j*size, size, size)
        end
    end
    ---------------------------------------
end
2

Is
“terrGen[i*j]”
supposed to give unique values for ex: i=0,j=1 or i=1,j=0?
In that case, the mirror effect is created because those coordinates point to the same index, 0. If you want unique values, consider
“terrGen[i][j]”. (:

3

Thank you :smile:

4

@Kire What I’m seeing in landscape mode is a 11x10 grid filled with blue or green squares in random positions. Each time I run it it’s a different random pattern. Not sure what you mean by a diagonal mirror effect.

EDIT: Never mind, I see what your referring to now.

EDIT: I think the problem is that the range of i and j are the same size and then you multiply i and j together. As you go thru the range, ij is the same as ji so I think thats what’s causing the mirror image effect.

5

Try this. This uses a multi demintion table.

displayMode(FULLSCREEN)

function setup()
    worldSize=10
    size=HEIGHT/worldSize
    --Color related
    col={color(0,255,0,255), color(0,0,255,255)}
    terrGen={}
    --Random color generation (decided from 1 to amount of colors)
    for i=0, (HEIGHT//size) do
        terrGen[i]={}                   --    create a multi dimension table
        for j=0, (HEIGHT//size) do
            --setting random numbers
            terrGen[i][j]=math.random(1, #col)
        end
    end
end

function draw()
    background(0)
    for i=0, (HEIGHT/size) do
        for j=0, (HEIGHT/size) do
            --copying the numbers over to a variable
            local c = terrGen[i][j]
            --selecting the color from the col table using variable c's numbers
            fill(col[c])
            --drawing squares
            rect(i*size,j*size, size, size)
        end
    end
end
6

Multi dimensional tables are an essential thing to learn, but if you really wanted to use a one dimensional table then using (j-1)*(HEIGHT//size)+i Should work instead of i*j, assuming (HEIGHT//size) is the maximum size of the table in the y dimension