Searching for a series of pixels

[exolon]

Hi,

I've been trying to make a simple bot to play the simple dodge-em-up Japanese game "TKKN". The game simply involves using the arrow keys to dodge a continuous barrage of bullets in space.

The problem is that the ship sprite doesn't seem to have any unique colours (due to lots of random background star colours), so a simple pixelsearch will turn up false matches.

To get around this, I've tried a horrible hack by first pixelsearching for a known colour in the sprite, then using PixelGetColor to check the next two pixels (i.e. I know that the sprite should have a purple pixel at position (x, y), and a red pixel at (x+1, y), and a white pixel at (x+2, y).

If not, then I recursively check the rest of the current line, then loop and search from the next line.

It probably works, but it's far too slow on my machine to ever be useful - it takes over a second and often over three seconds to find the sprite, by which time the game is over.

So I guess what's needed is a proper, fast function to search for an array of horizontal or vertical pixels rather than a single one. Has anyone had more success at this kind of thing?

Code in question:

Func FindShip($searchX, $searchY, $searchEndX, $searchEndY)
    ; x = l
    ; y = t
    ; endx = r
    ; endy = b
    ;ConsoleWrite("searching ..." & $searchX & ", " & $searchY)
    While $searchY <= $searchEndY
        ; find first pixel
        $foundPos = PixelSearch($searchX, $searchY, $searchEndX, $searchEndY, 0xFF00FF)
        If @error = 1 Then
            ;ConsoleWrite("not found anywhere in bounds " & $searchX & "," & $searchY & "," & $searchEndX & "," & $searchEndY & "!" & @CRLF)
            Return False
        EndIf
        ;ConsoleWrite("possible: " & $foundPos[0] & "," & $foundPos[1] & @CRLF)
        ; check second and third pixels for match
        If (PixelGetColor($foundPos[0]+1, $foundPos[1]) = 0xFF0000) And (PixelGetColor($foundPos[0]+2, $foundPos[1]) = 0xFFFFFF) Then
            ConsoleWrite("found at: " & $foundPos[0] & "," & $foundPos[1] & @CRLF)
            Return $foundPos
        Else
            ; check for more matches on this line...
            $moreMatches = FindShip($foundPos[0]+6, $foundPos[1], $searchEndX, $foundPos[1])
            If $moreMatches Then
                ConsoleWrite("recursively found at " & $moreMatches & @CRLF)
                Return $moreMatches
            EndIf
            ;ConsoleWrite("nope: next pixel colour = " & PixelGetColor($foundPos[0]+1, $foundPos[1], $hwnd) & @CRLF)
            ; else search next line...
            $searchY = $foundPos[1]+1
        EndIf
    WEnd
EndFunc

[bo8ster]

have you searched the forum? Many have posted pixel issues.

[exolon]

have you searched the forum? Many have posted pixel issues.

Hi Bo8ster,

Yes I searched and found many mentions of PixelSearch, but none talking about the need to search for more than a single pixel. If there's no library function that could do it, I think I'll have to write it in C and link it in somehow, if there's a FFI mechanism for AutoIt. Could be messy

[bo8ster]

I don't know the answer to your questions but i'm sure it has come up before. There are a few PixelSearch experts here but most get what they need and then leave.

Hope you find what you need in their posts.