AutoIt _ImageSearch and DllCall failure - dllimport

Question

I am trying to detect an image in a window. The window is BlueStacks App Player. I am using the ImageSearch UDF. Problem is it fails.
$result = DllCall("ImageSearchDLL.dll","str","ImageSearch","int",$x1,"int",$y1,"int",$right,"int",$bottom,"ptr",$findImage)
DllCall() should return an array if successful but returns 1 to indicate failure. I tried x86 and x64 versions of this UDF. This is how I call _ImageSearchArea():
_CaptureRegion()
_ImageSearchArea($gameImage, 0,0,0,500,500, $x, $y, 0)
I have Windows 7 X64. Also x64 AutoIt. The window's resolution is 577x690. This is the UDF I am using:
#include-once
; ------------------------------------------------------------------------------
;
; AutoIt Version: 3.0
; Language: English
; Description: Functions that assist with Image Search
; Require that the ImageSearchDLL.dll be loadable
;
; ------------------------------------------------------------------------------
;===============================================================================
;
; Description: Find the position of an image on the desktop
; Syntax: _ImageSearchArea, _ImageSearch
; Parameter(s):
; $findImage - the image to locate on the desktop
; $tolerance - 0 for no tolerance (0-255). Needed when colors of
; image differ from desktop. e.g GIF
; $resultPosition - Set where the returned x,y location of the image is.
; 1 for centre of image, 0 for top left of image
; $x $y - Return the x and y location of the image
;
; Return Value(s): On Success - Returns 1
; On Failure - Returns 0
;
; Note: Use _ImageSearch to search the entire desktop, _ImageSearchArea to specify
; a desktop region to search
;
;===============================================================================
Func _ImageSearch($findImage,$resultPosition,ByRef $x, ByRef $y,$tolerance)
return _ImageSearchArea($findImage,$resultPosition,0,0,#DesktopWidth,#DesktopHeight,$x,$y,$tolerance)
EndFunc
Func _ImageSearchArea($findImage,$resultPosition,$x1,$y1,$right,$bottom,ByRef $x, ByRef $y, $tolerance)
;MsgBox(0,"asd","" & $x1 & " " & $y1 & " " & $right & " " & $bottom)
if $tolerance>0 then $findImage = "*" & $tolerance & " " & $findImage
$result = DllCall("ImageSearchDLL.dll","str","ImageSearch","int",$x1,"int",$y1,"int",$right,"int",$bottom,"ptr",$findImage)
; If error exit
if $result[0]="0" then return 0
; Otherwise get the x,y location of the match and the size of the image to
; compute the centre of search
$array = StringSplit($result[0],"|")
$x=Int(Number($array[2]))
$y=Int(Number($array[3]))
if $resultPosition=1 then
$x=$x + Int(Number($array[4])/2)
$y=$y + Int(Number($array[5])/2)
endif
return 1
EndFunc
;===============================================================================
;
; Description: Wait for a specified number of seconds for an image to appear
;
; Syntax: _WaitForImageSearch, _WaitForImagesSearch
; Parameter(s):
; $waitSecs - seconds to try and find the image
; $findImage - the image to locate on the desktop
; $tolerance - 0 for no tolerance (0-255). Needed when colors of
; image differ from desktop. e.g GIF
; $resultPosition - Set where the returned x,y location of the image is.
; 1 for centre of image, 0 for top left of image
; $x $y - Return the x and y location of the image
;
; Return Value(s): On Success - Returns 1
; On Failure - Returns 0
;
;
;===============================================================================
Func _WaitForImageSearch($findImage,$waitSecs,$resultPosition,ByRef $x, ByRef $y,$tolerance)
$waitSecs = $waitSecs * 1000
$startTime=TimerInit()
While TimerDiff($startTime) < $waitSecs
sleep(100)
$result=_ImageSearch($findImage,$resultPosition,$x, $y,$tolerance)
if $result > 0 Then
return 1
EndIf
WEnd
return 0
EndFunc
;===============================================================================
;
; Description: Wait for a specified number of seconds for any of a set of
; images to appear
;
; Syntax: _WaitForImagesSearch
; Parameter(s):
; $waitSecs - seconds to try and find the image
; $findImage - the ARRAY of images to locate on the desktop
; - ARRAY[0] is set to the number of images to loop through
; ARRAY[1] is the first image
; $tolerance - 0 for no tolerance (0-255). Needed when colors of
; image differ from desktop. e.g GIF
; $resultPosition - Set where the returned x,y location of the image is.
; 1 for centre of image, 0 for top left of image
; $x $y - Return the x and y location of the image
;
; Return Value(s): On Success - Returns the index of the successful find
; On Failure - Returns 0
;
;
;===============================================================================
Func _WaitForImagesSearch($findImage,$waitSecs,$resultPosition,ByRef $x, ByRef $y,$tolerance)
$waitSecs = $waitSecs * 1000
$startTime=TimerInit()
While TimerDiff($startTime) < $waitSecs
for $i = 1 to $findImage[0]
sleep(100)
$result=_ImageSearch($findImage[$i],$resultPosition,$x, $y,$tolerance)
if $result > 0 Then
return $i
EndIf
Next
WEnd
return 0
EndFunc
$gameImage is an image I want to search for.

Answer 1

$findImage is a string variable, thus the dll call should look like this.
$result = DllCall("ImageSearchDLL.dll","str","ImageSearch","int",$x1,"int",$y1,"int",$right,"int",$bottom,"str",$findImage)