[VB6] Why does this keep creating a pattern?

[azkanan]

Why does the below keep creating a pattern, example image shown below.

The theory is that this should generate a grid-based map, based on the ID of each point in the array (AlphaSpace.area(0,63)).

ID 1 is a planet (blue), ID 2 is a second planet (red).

"i" generates the columns and "i" generates the rows… So for each passing of **"i"** it should generate 64 (including 0) ID spaces in the rows.

For each ID space, there is a 10% chance of planet 1 and a 10% chance of planet 2, with 80% chance of space… The process seems random, so

why is it making a godamn pattern?

Note: "i" and "i2" are Public variables.

```
For i = 0 To 63

For i2 = 0 To 63

x = Rand(1, 100)

If x > 0 And x < 10 Then

AlphaSpace.area(i, i2).ID = 1

ElseIf x >= 9 And x < 20 Then

AlphaSpace.area(i, i2).ID = 2

End If

Next i2

Next i
```


========================================================

This is my display code, which loads the graphics.

```

For i = 0 To 20

For i2 = 0 To 20

If AlphaSpace.area(i2, i).ID = 0 Then

SpacePic.Picture = LoadPicture(App.Path & "\graphics\spacemap\void.jpg")

ElseIf AlphaSpace.area(i2, i).ID = 1 Then

SpacePic.Picture = LoadPicture(App.Path & "\graphics\spacemap\planet.jpg")

ElseIf AlphaSpace.area(i2, i).ID = 2 Then

SpacePic.Picture = LoadPicture(App.Path & "\graphics\spacemap\planet2.jpg")

End If

'End If

SpacePicture.PaintPicture SpacePic, (i2 * 20), (i * 20)

Next i2

Next i

```

[azkanan]

And here is the Rand() function;

```

Public Function Rand(LowerNumber, HigherNumber)

Randomize

Rand = Int((HigherNumber - LowerNumber + 1) * Rnd) + LowerNumber

End Function

```

[kris_hole]

i'd suggest that it's because you're not using your random function as ridiculously enough.

There is no such thing as truly random generation in code. so there will always be a pattern. if you narrow it so simply "1-10,10-20"

You're gunna get pretty much the same results.

SO, i'd suggest instead of trying to randomly generate per tile in a loop. just use random tiles. something like

for i = 1 to max_objects

randx = 1 to screenwidth

randY = 1 to screen width

tile[x,y]= object.

Works better IMO

[DMF]

nice idea kris XD : ) that should do it for him

[azkanan]

> ' timestamp='1366317482' post='894413']
>
> i'd suggest that it's because you're not using your random function as ridiculously enough.
>
> There is no such thing as truly random generation in code. so there will always be a pattern. if you narrow it so simply "1-10,10-20"
>
> You're gunna get pretty much the same results.
>
> SO, i'd suggest instead of trying to randomly generate per tile in a loop. just use random tiles. something like
>
> for i = 1 to max_objects
>
> randx = 1 to screenwidth
>
> randY = 1 to screen width
>
> tile[x,y]= object.
>
> Works better IMO

```
Public Sub GenerateSpace()

Dim x As Integer

Dim i As Integer

Dim i2 As Integer

Dim emptytile As Integer

emptytile = 1

Do Until emptytile = 0

i = Rand(0, 63)

i2 = Rand(0, 63)

If AlphaSpace.area(i, i2).ID <> 0 Then

i = Rand(1, 63)

i2 = Rand(1, 63)

Else

x = Rand(1, 3)

Select Case x

Case 1: AlphaSpace.area(i, i2).ID = 1

Case 2: AlphaSpace.area(i, i2).ID = 2

Case 3: AlphaSpace.area(i, i2).ID = 3

End Select

End If

emptytile = 0

For i = 0 To 63

For i2 = 0 To 63

If AlphaSpace.area(i, i2).ID = 0 Then

emptytile = emptytile + 1

End If

Next i2

Next i

Loop

End Sub

```

Well, in theory it works, but in practice, the game freezes for a long, long time as it tries to cover all those tiles…

The problem is, there are 4096 tiles, so there's a 1/4096 chance every time it tries of actually filling a tile. Odds are against the computer hitting those last 2 or 3 empty tiles.

[azkanan]

5x5 (25), takes <1 second. Works fine.


[azkanan]

Turns out it's random if it crashes. So, I decided to make my zones smaller (63,63) to (29,29)…

Now, it loads quicker, I can fit it all in one viewscreen without need for scrolling, and I'm ready to move on with my game's development - thanks everyone for the help! 


[Exception]

Er. Could've just put a seed based on a manipulated calculation of the system time, for example, in your random function, or some other manipulable variable. 

Randomize can have an argument. That argument would be the seed used.